Ensure that the compiled structures respect the converter field.

In addition, fixed a bug that prevented client listeners from
receiving any packets.

ItemDisguise/.classpath

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.7"/>
+	<classpathentry kind="lib" path="D:/Games/Minecraft/Server Mods/API/bukkit-1.3.1-R2.0.jar"/>
+	<classpathentry kind="lib" path="/ProtocolLib/bin/ProtocolLib.jar"/>
+	<classpathentry kind="output" path="class"/>
+</classpath>

ItemDisguise/.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>ItemDisguise</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

ItemDisguise/.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,11 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.7
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=1.7
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.source=1.7

ItemDisguise/src/com/comphenix/itemdisguise/HideEnchantmentsListener.java

@@ -0,0 +1,119 @@
+/*
+ *  ItemDisguise - A simple Bukkit plugin that illustrates how to use ProtocolLib.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.itemdisguise;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.bukkit.Server;
+import org.bukkit.enchantments.Enchantment;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.plugin.java.JavaPlugin;
+
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.ConnectionSide;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.reflect.FieldAccessException;
+
+public class HideEnchantmentsListener {
+
+	private final Server server;
+	private final Logger logger;
+	
+	public HideEnchantmentsListener(Server server, Logger logger) {
+		this.server = server;
+		this.logger = logger;
+	}
+	
+	public void addListener(ProtocolManager protocolManager, JavaPlugin plugin) {
+
+		// Hide all enchantments
+		protocolManager.addPacketListener(new PacketAdapter(plugin, ConnectionSide.SERVER_SIDE, 0x67, 0x68, 0x3E) {
+			@Override
+			public void onPacketSending(PacketEvent event) {
+				PacketContainer packet = event.getPacket();
+				
+				try {
+					// Item packets
+					switch (event.getPacketID()) {
+					case 0x67: // Set slot
+						removeEnchantments(packet.getItemModifier().read(0));
+						break;
+						
+					case 0x68: // Set Window Items
+						ItemStack[] elements = packet.getItemArrayModifier().read(0);
+	
+						for (int i = 0; i < elements.length; i++) {
+							if (elements[i] != null) {
+								removeEnchantments(elements[i]);
+							}
+						}
+						break;
+						
+					case 0x3E: // Sound effect
+						event.setCancelled(true);
+						break;
+					}
+				
+				} catch (FieldAccessException e) {
+					logger.log(Level.SEVERE, "Couldn't access field.", e);
+				}
+			}
+		});
+		
+		// Censor
+		protocolManager.addPacketListener(new PacketAdapter(plugin, ConnectionSide.CLIENT_SIDE, 0x3) {
+			@Override
+			public void onPacketReceiving(PacketEvent event) {
+				if (event.getPacketID() == 0x3) {
+					try {
+						String message = event.getPacket().
+											getSpecificModifier(String.class).read(0);
+						
+						if (message.contains("shit") || message.contains("fuck")) {
+							event.setCancelled(true);
+							event.getPlayer().sendMessage("Bad manners!");
+						}
+						
+					} catch (FieldAccessException e) {
+						logger.log(Level.SEVERE, "Couldn't access field.", e);
+					}
+				}
+			}
+		});
+	}
+	
+	public Server getServer() {
+		return server;
+	}
+	
+	public void removeListener(ProtocolManager protocolManager, JavaPlugin plugin) {
+		// Just remove every adapter with this plugin
+		protocolManager.removePacketListeners(plugin);
+	}
+	
+	private void removeEnchantments(ItemStack stack) {
+		Object[] copy = stack.getEnchantments().keySet().toArray();
+		
+		for (Object enchantment : copy) {
+			stack.removeEnchantment((Enchantment) enchantment);
+		}
+	}
+}

ItemDisguise/src/com/comphenix/itemdisguise/ItemDisguiseMod.java

@@ -0,0 +1,99 @@
+/*
+ *  ItemDisguise - A simple Bukkit plugin that illustrates how to use ProtocolLib.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.itemdisguise;
+
+import java.util.logging.Logger;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.java.JavaPlugin;
+
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.PacketContainer;
+
+public class ItemDisguiseMod extends JavaPlugin {
+	
+	private ProtocolManager protocolManager;
+	private Logger logger;
+	
+	private HideEnchantmentsListener enchantmentsListener;
+	
+	@Override
+	public void onEnable() {
+
+		logger = getLoggerSafely();
+		protocolManager = ProtocolLibrary.getProtocolManager();
+		
+		enchantmentsListener = new HideEnchantmentsListener(getServer(), logger);
+		enchantmentsListener.addListener(protocolManager, this);
+	}
+
+	@Override
+	public void onDisable() {
+		enchantmentsListener.removeListener(protocolManager, this);
+	}
+	
+	@Override
+	public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+		if (sender instanceof Player) {
+		
+			Player player = (Player) sender;
+			
+			if (label.equalsIgnoreCase("explosion")) {
+				PacketContainer fakeExplosion = protocolManager.createPacket(0x3C);
+				
+				// Set the coordinates
+				try {
+					fakeExplosion.getSpecificModifier(double.class).
+					    write(0, player.getLocation().getX()).
+					    write(1, player.getLocation().getY()).
+					    write(2, player.getLocation().getZ());
+					fakeExplosion.getSpecificModifier(float.class).
+						write(0, 3.0F);
+
+					protocolManager.sendServerPacket(player, fakeExplosion);
+					
+				} catch (Exception e) {
+					e.printStackTrace();
+				}
+			}
+			
+			return true;
+		}
+		
+		return false;
+	}
+	
+	// Get the Bukkit logger first, before we try to create our own
+	private Logger getLoggerSafely() {
+		
+		Logger log = null;
+	
+		try {
+			log = getLogger();
+		} catch (Throwable e) {
+			// We'll handle it
+		}
+		
+		if (log == null)
+			log = Logger.getLogger("Minecraft");
+		return log;
+	}
+}

ItemDisguise/src/plugin.yml

@@ -0,0 +1,14 @@
+name: ItemDisguiseMod
+version: 1.0.0
+description: Change the appearance of inventory items.
+author: Comphenix
+website: http://www.comphenix.net/ItemDisguise
+
+main: com.comphenix.itemdisguise.ItemDisguiseMod
+depends: [ProtocolLib]
+database: false
+
+commands:
+   explosion:
+      description: Creates a fake explosion around the caller.
+      usage: /<command>

ProtocolLib/src/com/comphenix/protocol/Application.java

@@ -1,3 +1,20 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol;
 
 public class Application {

ProtocolLib/src/com/comphenix/protocol/AsynchronousManager.java

@@ -0,0 +1,78 @@
+package com.comphenix.protocol;
+
+import java.util.Set;
+import java.util.logging.Logger;
+
+import org.bukkit.plugin.Plugin;
+
+import com.comphenix.protocol.async.AsyncListenerHandler;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.events.PacketListener;
+
+/**
+ * Represents a asynchronous packet handler.
+ * 
+ * @author Kristian
+ */
+public interface AsynchronousManager {
+
+	/**
+	 * Registers an asynchronous packet handler.
+	 * <p>
+	 * To start listening asynchronously, pass the getListenerLoop() runnable to a different thread.
+	 * @param plugin - the plugin that is registering the handler.
+	 * @param listener - the packet listener that will recieve these asynchronous events.
+	 * @return An asynchrouns handler.
+	 */
+	public abstract AsyncListenerHandler registerAsyncHandler(PacketListener listener);
+
+	/**
+	 * Unregisters and closes the given asynchronous handler.
+	 * @param handler - asynchronous handler.
+	 */
+	public abstract void unregisterAsyncHandler(AsyncListenerHandler handler);
+
+	/**
+	 * Unregisters every asynchronous handler associated with this plugin.
+	 * @param plugin - the original plugin.
+	 */
+	public void unregisterAsyncHandlers(Plugin plugin);
+	
+	/**
+	 * Retrieves a immutable set containing the ID of the sent server packets that will be 
+	 * observed by the asynchronous listeners.
+	 * @return Every filtered server packet.
+	 */
+	public abstract Set<Integer> getSendingFilters();
+
+	/**
+	 * Retrieves a immutable set containing the ID of the recieved client packets that will be
+	 * observed by the asynchronous listeners.
+	 * @return Every filtered client packet.
+	 */
+	public abstract Set<Integer> getReceivingFilters();
+
+	/**
+	 * Determine if a given synchronous packet has asynchronous listeners.
+	 * @param packet - packet to test.
+	 * @return TRUE if it does, FALSE otherwise.
+	 */
+	public abstract boolean hasAsynchronousListeners(PacketEvent packet);
+
+	/**
+	 * Retrieve the default packet stream.
+	 * @return Default packet stream.
+	 */
+	public abstract PacketStream getPacketStream();
+
+	/**
+	 * Retrieve the default error logger.
+	 * @return Default logger.
+	 */
+	public abstract Logger getLogger();
+
+	/**
+	 * Remove listeners, close threads and transmit every delayed packet.
+	 */
+	public abstract void cleanupAll();
+}

ProtocolLib/src/com/comphenix/protocol/PacketStream.java

@@ -0,0 +1,55 @@
+package com.comphenix.protocol;
+
+import java.lang.reflect.InvocationTargetException;
+
+import org.bukkit.entity.Player;
+
+import com.comphenix.protocol.events.PacketContainer;
+
+/**
+ * Represents a object capable of sending or receiving packets.
+ * 
+ * @author Kristian
+ */
+public interface PacketStream {
+	
+	/**
+	 * Send a packet to the given player.
+	 * @param reciever - the reciever.
+	 * @param packet - packet to send.
+	 * @throws InvocationTargetException - if an error occured when sending the packet.
+	 */
+	public void sendServerPacket(Player reciever, PacketContainer packet) 
+			throws InvocationTargetException;
+
+	/**
+	 * Send a packet to the given player.
+	 * @param reciever - the reciever.
+	 * @param packet - packet to send.
+	 * @param filters - whether or not to invoke any packet filters.
+	 * @throws InvocationTargetException - if an error occured when sending the packet.
+	 */
+	public void sendServerPacket(Player reciever, PacketContainer packet, boolean filters)
+			throws InvocationTargetException;
+
+	/**
+	 * Simulate recieving a certain packet from a given player.
+	 * @param sender - the sender.
+	 * @param packet - the packet that was sent.
+	 * @throws InvocationTargetException If the reflection machinery failed.
+	 * @throws IllegalAccessException If the underlying method caused an error.
+	 */
+	public void recieveClientPacket(Player sender, PacketContainer packet) 
+			throws IllegalAccessException, InvocationTargetException;
+
+	/**
+	 * Simulate recieving a certain packet from a given player.
+	 * @param sender - the sender.
+	 * @param packet - the packet that was sent.
+	 * @param filters - whether or not to invoke any packet filters.
+	 * @throws InvocationTargetException If the reflection machinery failed.
+	 * @throws IllegalAccessException If the underlying method caused an error.
+	 */
+	public void recieveClientPacket(Player sender, PacketContainer packet, boolean filters)
+			throws IllegalAccessException, InvocationTargetException;
+}

ProtocolLib/src/com/comphenix/protocol/Packets.java

@@ -0,0 +1,198 @@
+package com.comphenix.protocol;
+
+import com.comphenix.protocol.reflect.IntEnum;
+
+/**
+ * List of known packet IDs since 1.3.2.
+ * 
+ * @author Kristian
+ */
+public final class Packets {
+	
+	/**
+	 * List of packets sent only by the server.
+	 * @author Kristian
+	 */
+	public static final class Server extends IntEnum {
+		/**
+		 * The singleton instance. Can also be retrieved from the parent class.
+		 */
+		private static Server INSTANCE = new Server();
+		
+		public static final int KEEP_ALIVE = 0;
+		public static final int LOGIN = 1;
+		public static final int CHAT = 3;
+		public static final int UPDATE_TIME = 4;
+		public static final int ENTITY_EQUIPMENT = 5;
+		public static final int SPAWN_POSITION = 6;
+		public static final int UPDATE_HEALTH = 8;
+		public static final int RESPAWN = 9;
+		public static final int FLYING = 10;
+		public static final int PLAYER_POSITION = 11;
+		public static final int PLAYER_LOOK = 12;
+		public static final int PLAYER_LOOK_MOVE = 13;
+		public static final int ENTITY_LOCATION_ACTION = 17;
+		public static final int ARM_ANIMATION = 18;
+		public static final int NAMED_ENTITY_SPAWN = 20;
+		public static final int PICKUP_SPAWN = 21;
+		public static final int COLLECT = 22;
+		public static final int VEHICLE_SPAWN = 23;
+		public static final int MOB_SPAWN = 24;
+		public static final int ENTITY_PAINTING = 25;
+		public static final int ADD_EXP_ORB = 26;
+		public static final int ENTITY_VELOCITY = 28;
+		public static final int DESTROY_ENTITY = 29;
+		public static final int ENTITY = 30;
+		public static final int REL_ENTITY_MOVE = 31;
+		public static final int ENTITY_LOOK = 32;
+		public static final int REL_ENTITY_MOVE_LOOK = 33;
+		public static final int ENTITY_TELEPORT = 34;
+		public static final int ENTITY_HEAD_ROTATION = 35;
+		public static final int ENTITY_STATUS = 38;
+		public static final int ATTACH_ENTITY = 39;
+		public static final int ENTITY_METADATA = 40;
+		public static final int MOB_EFFECT = 41;
+		public static final int REMOVE_MOB_EFFECT = 42;
+		public static final int SET_EXPERIENCE = 43;
+		public static final int MAP_CHUNK = 51;
+		public static final int MULTI_BLOCK_CHANGE = 52;
+		public static final int BLOCK_CHANGE = 53;
+		public static final int PLAY_NOTE_BLOCK = 54;
+		public static final int BLOCK_BREAK_ANIMATION = 55;
+		public static final int MAP_CHUNK_BULK = 56;
+		public static final int EXPLOSION = 60;
+		public static final int WORLD_EVENT = 61;
+		public static final int NAMED_SOUND_EFFECT = 62;
+		public static final int BED = 70;
+		public static final int WEATHER = 71;
+		public static final int OPEN_WINDOW = 100;
+		public static final int CLOSE_WINDOW = 101;
+		public static final int SET_SLOT = 103;
+		public static final int WINDOW_ITEMS = 104;
+		public static final int CRAFT_PROGRESS_BAR = 105;
+		public static final int TRANSACTION = 106;
+		public static final int SET_CREATIVE_SLOT = 107;
+		public static final int UPDATE_SIGN = 130;
+		public static final int ITEM_DATA = 131;
+		public static final int TILE_ENTITY_DATA = 132;
+		public static final int STATISTIC = 200;
+		public static final int PLAYER_INFO = 201;
+		public static final int ABILITIES = 202;
+		public static final int TAB_COMPLETE = 203;
+		public static final int CUSTOM_PAYLOAD = 250;
+		public static final int KEY_RESPONSE = 252;
+		public static final int KEY_REQUEST = 253;
+		public static final int KICK_DISCONNECT = 255;
+		
+		/**
+		 * A registry that parses between names and packet IDs.
+		 * @return The current server registry.
+		 */
+		public static Server getRegistry() {
+			return INSTANCE;
+		}
+		
+		// We only allow a single instance of this class
+	    private Server() {
+			super();
+		}
+	}
+	
+	/**
+	 * List of packets sent by the client.
+	 * @author Kristian
+	 */
+	public static class Client extends IntEnum {
+		/**
+		 * The singleton instance. Can also be retrieved from the parent class.
+		 */
+		private static Client INSTANCE = new Client();
+		
+		public static final int KEEP_ALIVE = 0;
+		public static final int LOGIN = 1;
+		public static final int HANDSHAKE = 2;
+		public static final int CHAT = 3;
+		public static final int USE_ENTITY = 7;
+		public static final int RESPAWN = 9;
+		public static final int FLYING = 10;
+		public static final int PLAYER_POSITION = 11;
+		public static final int PLAYER_LOOK = 12;
+		public static final int PLAYER_LOOK_MOVE = 13;
+		public static final int BLOCK_DIG = 14;
+		public static final int PLACE = 15;
+		public static final int BLOCK_ITEM_SWITCH = 16;
+		public static final int ARM_ANIMATION = 18;
+		public static final int ENTITY_ACTION = 19;
+		public static final int CLOSE_WINDOW = 101;
+		public static final int WINDOW_CLICK = 102;
+		public static final int TRANSACTION = 106;
+		public static final int SET_CREATIVE_SLOT = 107;
+		public static final int BUTTON_CLICK = 108;
+		public static final int UPDATE_SIGN = 130;
+		public static final int ABILITIES = 202;
+		public static final int TAB_COMPLETE = 203;
+		public static final int LOCALE_AND_VIEW_DISTANCE = 204;
+		public static final int CLIENT_COMMAND = 205;
+		public static final int CUSTOM_PAYLOAD = 250;
+		public static final int KEY_RESPONSE = 252;
+		public static final int GET_INFO = 254;
+		public static final int KICK_DISCONNECT = 255;
+		
+		/**
+		 * A registry that parses between names and packet IDs.
+		 * @return The current client registry.
+		 */
+		public static Client getRegistry() {
+			return INSTANCE;
+		}
+		
+		// Like above
+		private Client() {
+			super();
+		}
+	}
+	
+	/**
+	 * A registry that parses between names and packet IDs.
+	 * @return The current client registry.
+	 */
+	public static Server getServerRegistry() {
+		return Server.getRegistry();
+	}
+
+	/**
+	 * A registry that parses between names and packet IDs.
+	 * @return The current server registry.
+	 */
+	public static Client getClientRegistry() {
+		return Client.INSTANCE;
+	}
+	
+	/**
+	 * Find a packet by name. Must be capitalized and use underscores.
+	 * @param name - name of packet to find.
+	 * @return The packet ID found.
+	 */
+	public static int valueOf(String name) {
+		Integer serverAttempt = Server.INSTANCE.valueOf(name);
+		
+		if (serverAttempt != null)
+			return serverAttempt;
+		else
+			return Client.INSTANCE.valueOf(name);
+	}
+	
+	/**
+	 * Retrieves the name of a packet.
+	 * @param packetID - packet to retrieve name.
+	 * @return The name, or NULL if unable to find such a packet.
+	 */
+	public static String getDeclaredName(int packetID) {
+		String serverAttempt = Server.INSTANCE.getDeclaredName(packetID);
+		
+		if (serverAttempt != null)
+			return serverAttempt;
+		else
+			return Client.INSTANCE.getDeclaredName(packetID);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/ProtocolLibrary.java

@@ -1,12 +1,34 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol;
 
+import java.io.IOException;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import org.bukkit.Server;
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
 
+import com.comphenix.protocol.async.AsyncFilterManager;
 import com.comphenix.protocol.injector.PacketFilterManager;
+import com.comphenix.protocol.metrics.Statistics;
+import com.comphenix.protocol.reflect.compiler.BackgroundCompiler;
 
 public class ProtocolLibrary extends JavaPlugin {
 	
@@ -15,11 +37,23 @@ public class ProtocolLibrary extends JavaPlugin {
 	
 	// Error logger
 	private Logger logger;
-
+	
+	// Metrics and statistisc
+	private Statistics statistisc;
+	
+	// Structure compiler
+	private BackgroundCompiler backgroundCompiler;
+	
+	// Used to clean up server packets that have expired. 
+	// But mostly required to simulate recieving client packets.
+	private int asyncPacketTask = -1;
+	private int tickCounter = 0;
+	private static final int ASYNC_PACKET_DELAY = 1;
+	
 	@Override
 	public void onLoad() {
 		logger = getLoggerSafely();
-		protocolManager = new PacketFilterManager(getClassLoader(), logger);
+		protocolManager = new PacketFilterManager(getClassLoader(), getServer(), logger);
 	}
 	
 	@Override
@@ -27,24 +61,107 @@ public class ProtocolLibrary extends JavaPlugin {
 		Server server = getServer();
 		PluginManager manager = server.getPluginManager();
 		
+		// Initialize background compiler
+		if (backgroundCompiler == null) {
+			backgroundCompiler = new BackgroundCompiler(getClassLoader());
+			BackgroundCompiler.setInstance(backgroundCompiler);
+		}
+
+		// Notify server managers of incompatible plugins
+		checkForIncompatibility(manager);
+		
 		// Player login and logout events
 		protocolManager.registerEvents(manager, this);
-		protocolManager.initializePlayers(server.getOnlinePlayers());
-	}
 		
+		// Inject our hook into already existing players
+		protocolManager.initializePlayers(server.getOnlinePlayers());
+		
+		// Timeout
+		createAsyncTask(server);
+		
+		// Try to enable statistics
+		try {
+			statistisc = new Statistics(this);
+		} catch (IOException e) {
+			logger.log(Level.SEVERE, "Unable to enable metrics.", e);
+		} catch (Throwable e) {
+			logger.log(Level.SEVERE, "Metrics cannot be enabled. Incompatible Bukkit version.", e);
+		}
+	}
+	
+	private void createAsyncTask(Server server) {
+		try {
+			if (asyncPacketTask >= 0)
+				throw new IllegalStateException("Async task has already been created");
+			
+			// Attempt to create task
+			asyncPacketTask = server.getScheduler().scheduleSyncRepeatingTask(this, new Runnable() {
+				@Override
+				public void run() {
+					AsyncFilterManager manager = (AsyncFilterManager) protocolManager.getAsynchronousManager();
+					
+					// We KNOW we're on the main thread at the moment
+					manager.sendProcessedPackets(tickCounter++, true);
+				}
+			}, ASYNC_PACKET_DELAY, ASYNC_PACKET_DELAY);
+		
+		} catch (Throwable e) {
+			if (asyncPacketTask == -1) {
+				logger.log(Level.SEVERE, "Unable to create packet timeout task.", e);
+			}
+		}
+	}
+	
+	private void checkForIncompatibility(PluginManager manager) {
+		// Plugin authors: Notify me to remove these
+		String[] incompatiblePlugins = {};
+		
+		for (String plugin : incompatiblePlugins) {
+			if (manager.getPlugin(plugin) != null) {
+				// Check for versions, ect.
+				logger.severe("Detected incompatible plugin: " + plugin);
+			}
+		}
+	}
+	
 	@Override
 	public void onDisable() {
+		// Disable compiler
+		if (backgroundCompiler != null) {
+			backgroundCompiler.shutdownAll();
+			backgroundCompiler = null;
+			BackgroundCompiler.setInstance(null);
+		}
+		
+		// Clean up
+		if (asyncPacketTask >= 0) {
+			getServer().getScheduler().cancelTask(asyncPacketTask);
+			asyncPacketTask = -1;
+		}
+		
 		protocolManager.close();
+		protocolManager = null;
+		statistisc = null;
 	}
-
+	
 	/**
 	 * Retrieves the packet protocol manager.
-	 * @return Packet protocol manager.
+	 * @return Packet protocol manager, or NULL if it has been disabled.
 	 */
 	public static ProtocolManager getProtocolManager() {
 		return protocolManager;
 	}
 	
+	/**
+	 * Retrieve the metrics instance used to measure users of this library.
+	 * <p>
+	 * Note that this method may return NULL when the server is reloading or shutting down.
+	 * @return Metrics instance container.
+	 */
+	public Statistics getStatistics() {
+		return statistisc;
+	}
+	
 	// Get the Bukkit logger first, before we try to create our own
 	private Logger getLoggerSafely() {
 		

ProtocolLib/src/com/comphenix/protocol/ProtocolManager.java

@@ -1,73 +1,70 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol;
 
-import java.lang.reflect.InvocationTargetException;
+import java.util.List;
 import java.util.Set;
 
+import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
 
 import com.comphenix.protocol.events.PacketContainer;
 import com.comphenix.protocol.events.PacketListener;
+import com.comphenix.protocol.injector.PacketConstructor;
+import com.comphenix.protocol.reflect.FieldAccessException;
 import com.google.common.collect.ImmutableSet;
 
-public interface ProtocolManager {
+/**
+ * Represents an API for accessing the Minecraft protocol.
+ * @author Kristian
+ */
+public interface ProtocolManager extends PacketStream {
 
 	/**
 	 * Retrieves a list of every registered packet listener.
 	 * @return Every registered packet listener.
 	 */
-	public abstract ImmutableSet<PacketListener> getPacketListeners();
+	public ImmutableSet<PacketListener> getPacketListeners();
 
 	/**
-	 * Adds a packet listener.
+	 * Adds a packet listener. 
+	 * <p>
+	 * Adding an already registered listener has no effect. If you need to change the packets 
+	 * the current listener is observing, you must first remove the packet listener before you 
+	 * can register it again.
 	 * @param listener - new packet listener.
 	 */
-	public abstract void addPacketListener(PacketListener listener);
+	public void addPacketListener(PacketListener listener);
 
 	/**
-	 * Removes a given packet listener.
+	 * Removes a given packet listener. 
+	 * <p>
+	 * Attempting to remove a listener that doesn't exist has no effect.
 	 * @param listener - the packet listener to remove.
 	 */
-	public abstract void removePacketListener(PacketListener listener);
+	public void removePacketListener(PacketListener listener);
 
 	/**
-	 * Send a packet to the given player.
-	 * @param reciever - the reciever.
-	 * @param packet - packet to send.
-	 * @throws InvocationTargetException - if an error occured when sending the packet.
+	 * Removes every listener associated with the given plugin.
+	 * @param plugin - the plugin to unload.
 	 */
-	public void sendServerPacket(Player reciever, PacketContainer packet) 
-			throws InvocationTargetException;
-
-	/**
-	 * Send a packet to the given player.
-	 * @param reciever - the reciever.
-	 * @param packet - packet to send.
-	 * @param filters - whether or not to invoke any packet filters.
-	 * @throws InvocationTargetException - if an error occured when sending the packet.
-	 */
-	public void sendServerPacket(Player reciever, PacketContainer packet, boolean filters)
-			throws InvocationTargetException;
-
-	/**
-	 * Simulate recieving a certain packet from a given player.
-	 * @param sender - the sender.
-	 * @param packet - the packet that was sent.
-	 * @throws InvocationTargetException If the reflection machinery failed.
-	 * @throws IllegalAccessException If the underlying method caused an error.
-	 */
-	public void recieveClientPacket(Player sender, PacketContainer packet) 
-			throws IllegalAccessException, InvocationTargetException;
-
-	/**
-	 * Simulate recieving a certain packet from a given player.
-	 * @param sender - the sender.
-	 * @param packet - the packet that was sent.
-	 * @param filters - whether or not to invoke any packet filters.
-	 * @throws InvocationTargetException If the reflection machinery failed.
-	 * @throws IllegalAccessException If the underlying method caused an error.
-	 */
-	public void recieveClientPacket(Player sender, PacketContainer packet, boolean filters)
-			throws IllegalAccessException, InvocationTargetException;
+	public void removePacketListeners(Plugin plugin);
 
 	/**
 	 * Constructs a new encapsulated Minecraft packet with the given ID.
@@ -75,16 +72,60 @@ public interface ProtocolManager {
 	 * @return New encapsulated Minecraft packet.
 	 */
 	public PacketContainer createPacket(int id);
-
+	
 	/**
-	 * Retieves a set of every enabled packet.
-	 * @return Every packet filter.
+	 * Constructs a new encapsulated Minecraft packet with the given ID.
+	 * <p>
+	 * If set to true, the <i>forceDefaults</i> option will force the system to automatically 
+	 * give non-primitive fields in the packet sensible default values. For instance, certain
+	 * packets - like Packet60Explosion - require a List or Set to be non-null. If the
+	 * forceDefaults option is true, the List or Set will be automatically created.
+	 * 
+	 * @param id - packet ID.
+	 * @param forceDefaults - TRUE to use sensible defaults in most fields, FALSE otherwise.
+	 * @return New encapsulated Minecraft packet.
 	 */
-	public Set<Integer> getPacketFilters();
+	public PacketContainer createPacket(int id, boolean forceDefaults);
 
 	/**
-	 * Determines whether or not is protocol mananger has been disabled. 
+	 * Construct a packet using the special builtin Minecraft constructors.
+	 * @param id - the packet ID.
+	 * @param arguments - arguments that will be passed to the constructor.
+	 * @return The packet constructor.
+	 */
+	public PacketConstructor createPacketConstructor(int id, Object... arguments);
+	
+	/**
+	 * Completely refresh all clients about an entity.
+	 * <p>
+	 * Note that this method is NOT thread safe. If you call this method from anything 
+	 * but the main thread, it will throw an exception.
+	 * @param entity - entity to refresh.
+	 * @param observers - the clients to update.
+	 */
+	public void updateEntity(Entity entity, List<Player> observers) throws FieldAccessException;
+	
+	/**
+	 * Retrieves a immutable set containing the ID of the sent server packets that will be observed by listeners.
+	 * @return Every filtered server packet.
+	 */
+	public Set<Integer> getSendingFilters();
+	
+	/**
+	 * Retrieves a immutable set containing the ID of the recieved client packets that will be observed by listeners.
+	 * @return Every filtered client packet.
+	 */
+	public Set<Integer> getReceivingFilters();
+	
+	/**
+	 * Determines whether or not this protocol mananger has been disabled. 
 	 * @return TRUE if it has, FALSE otherwise.
 	 */
 	public boolean isClosed();
+
+	/**
+	 * Retrieve the current asyncronous packet manager.
+	 * @return Asyncronous packet manager.
+	 */
+	public AsynchronousManager getAsynchronousManager();
 }

ProtocolLib/src/com/comphenix/protocol/async/AsyncFilterManager.java

@@ -0,0 +1,301 @@
+package com.comphenix.protocol.async;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Logger;
+
+import org.bukkit.plugin.Plugin;
+import org.bukkit.scheduler.BukkitScheduler;
+
+import com.comphenix.protocol.AsynchronousManager;
+import com.comphenix.protocol.PacketStream;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.ListeningWhitelist;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.events.PacketListener;
+import com.comphenix.protocol.injector.PacketFilterManager;
+import com.comphenix.protocol.injector.PrioritizedListener;
+import com.google.common.base.Objects;
+
+/**
+ * Represents a filter manager for asynchronous packets.
+ * 
+ * @author Kristian
+ */
+public class AsyncFilterManager implements AsynchronousManager {
+
+	private PacketProcessingQueue serverProcessingQueue;
+	private PacketSendingQueue serverQueue;
+	
+	private PacketProcessingQueue clientProcessingQueue;
+	private PacketSendingQueue clientQueue;
+	
+	private Logger logger;
+	
+	// The likely main thread
+	private Thread mainThread;
+	
+	// Default scheduler
+	private BukkitScheduler scheduler;
+	
+	// Our protocol manager
+	private ProtocolManager manager;
+	
+	// Current packet index
+	private AtomicInteger currentSendingIndex = new AtomicInteger();
+	
+	// Whether or not we're currently cleaning up
+	private volatile boolean cleaningUp;
+	
+	public AsyncFilterManager(Logger logger, BukkitScheduler scheduler, ProtocolManager manager) {
+		
+		// Server packets are synchronized already
+		this.serverQueue = new PacketSendingQueue(false);
+		// Client packets must be synchronized
+		this.clientQueue = new PacketSendingQueue(true); 
+		
+		this.serverProcessingQueue = new PacketProcessingQueue(serverQueue);
+		this.clientProcessingQueue = new PacketProcessingQueue(clientQueue);
+		
+		this.scheduler = scheduler;
+		this.manager = manager;
+		
+		this.logger = logger;
+		this.mainThread = Thread.currentThread();
+	}
+	
+	@Override
+	public AsyncListenerHandler registerAsyncHandler(PacketListener listener) {
+		AsyncListenerHandler handler = new AsyncListenerHandler(mainThread, this, listener);
+		
+		ListeningWhitelist sendingWhitelist = listener.getSendingWhitelist();
+		ListeningWhitelist receivingWhitelist = listener.getReceivingWhitelist();
+		
+		// We need a synchronized listener to get the ball rolling
+		boolean hasListener = true;
+		
+		// Add listener to either or both processing queue
+		if (hasValidWhitelist(sendingWhitelist)) {
+			PacketFilterManager.verifyWhitelist(listener, sendingWhitelist);
+			serverProcessingQueue.addListener(handler, sendingWhitelist);
+			hasListener &= hasPacketListener(sendingWhitelist); 
+		}
+		
+		if (hasValidWhitelist(receivingWhitelist)) {
+			PacketFilterManager.verifyWhitelist(listener, receivingWhitelist);
+			clientProcessingQueue.addListener(handler, receivingWhitelist);
+			hasListener &= hasPacketListener(receivingWhitelist); 
+		}
+		
+		if (!hasListener) {
+			handler.setNullPacketListener(new NullPacketListener(listener));
+			manager.addPacketListener(handler.getNullPacketListener());
+		}
+		
+		return handler;
+	}
+	
+	/**
+	 * Determine if the given packets are represented.
+	 * @param whitelist - list of packets.
+	 * @return TRUE if they are all registered, FALSE otherwise.
+	 */
+	private boolean hasPacketListener(ListeningWhitelist whitelist) {
+		return manager.getSendingFilters().containsAll(whitelist.getWhitelist());
+	}
+	
+	private boolean hasValidWhitelist(ListeningWhitelist whitelist) {
+		return whitelist != null && whitelist.getWhitelist().size() > 0;
+	}
+	
+	@Override
+	public void unregisterAsyncHandler(AsyncListenerHandler handler) {
+		if (handler == null)
+			throw new IllegalArgumentException("listenerToken cannot be NULL");
+		
+		handler.cancel();	
+	}
+	
+	// Called by AsyncListenerHandler
+	void unregisterAsyncHandlerInternal(AsyncListenerHandler handler) {
+		
+		PacketListener listener = handler.getAsyncListener();
+		boolean synchronusOK = onMainThread();
+		
+		// Unregister null packet listeners
+		if (handler.getNullPacketListener() != null) {
+			manager.removePacketListener(handler.getNullPacketListener());
+		}
+		
+		// Just remove it from the queue(s)
+		if (hasValidWhitelist(listener.getSendingWhitelist())) {
+			List<Integer> removed = serverProcessingQueue.removeListener(handler, listener.getSendingWhitelist());
+			
+			// We're already taking care of this, so don't do anything
+			if (!cleaningUp)
+				serverQueue.signalPacketUpdate(removed, synchronusOK);
+		}
+		
+		if (hasValidWhitelist(listener.getReceivingWhitelist())) {
+			List<Integer> removed = clientProcessingQueue.removeListener(handler, listener.getReceivingWhitelist());
+			
+			if (!cleaningUp)
+				clientQueue.signalPacketUpdate(removed, synchronusOK);
+		}
+	}
+	
+	/**
+	 * Determine if we're running on the main thread.
+	 * @return TRUE if we are, FALSE otherwise.
+	 */
+	private boolean onMainThread() {
+		return Thread.currentThread().getId() == mainThread.getId();
+	}
+	
+	@Override
+	public void unregisterAsyncHandlers(Plugin plugin) {
+		unregisterAsyncHandlers(serverProcessingQueue, plugin);
+		unregisterAsyncHandlers(clientProcessingQueue, plugin);
+	}
+	
+	private void unregisterAsyncHandlers(PacketProcessingQueue processingQueue, Plugin plugin) {
+		
+		// Iterate through every packet listener
+		for (PrioritizedListener<AsyncListenerHandler> listener : processingQueue.values()) {			
+			// Remove the listener
+			if (Objects.equal(listener.getListener().getPlugin(), plugin)) {
+				unregisterAsyncHandler(listener.getListener());
+			}
+		}
+	}
+	
+	/**
+	 * Enqueue a packet for asynchronous processing.
+	 * @param syncPacket - synchronous packet event.
+	 * @param asyncMarker - the asynchronous marker to use.
+	 */
+	public void enqueueSyncPacket(PacketEvent syncPacket, AsyncMarker asyncMarker) {
+		PacketEvent newEvent = PacketEvent.fromSynchronous(syncPacket, asyncMarker);
+		
+		// Start the process
+		getSendingQueue(syncPacket).enqueue(newEvent);
+		
+		// We know this is occuring on the main thread, to pass TRUE
+		getProcessingQueue(syncPacket).enqueue(newEvent, true);
+	}
+	
+	@Override
+	public Set<Integer> getSendingFilters() {
+		return serverProcessingQueue.keySet();
+	}
+	
+	@Override
+	public Set<Integer> getReceivingFilters() {
+		return clientProcessingQueue.keySet();
+	}
+	
+	/**
+	 * Used to create a default asynchronous task.
+	 * @param plugin - the calling plugin.
+	 * @param runnable - the runnable.
+	 */
+	public void scheduleAsyncTask(Plugin plugin, Runnable runnable) {
+		scheduler.scheduleAsyncDelayedTask(plugin, runnable);
+	}
+	
+	@Override
+	public boolean hasAsynchronousListeners(PacketEvent packet) {
+		 Collection<?> list = getProcessingQueue(packet).getListener(packet.getPacketID());
+		 return list != null && list.size() > 0;
+	}
+	
+	/**
+	 * Construct a asynchronous marker with all the default values.
+	 * @return Asynchronous marker.
+	 */
+	public AsyncMarker createAsyncMarker() {
+		return createAsyncMarker(AsyncMarker.DEFAULT_SENDING_DELTA, AsyncMarker.DEFAULT_TIMEOUT_DELTA);
+	}
+	
+	/**
+	 * Construct an async marker with the given sending priority delta and timeout delta.
+	 * @param sendingDelta - how many packets we're willing to wait.
+	 * @param timeoutDelta - how long (in ms) until the packet expire.
+	 * @return An async marker.
+	 */
+	public AsyncMarker createAsyncMarker(long sendingDelta, long timeoutDelta) {
+		return createAsyncMarker(sendingDelta, timeoutDelta, 
+								 currentSendingIndex.incrementAndGet(), System.currentTimeMillis());
+	}
+	
+	// Helper method
+	private AsyncMarker createAsyncMarker(long sendingDelta, long timeoutDelta, long sendingIndex, long currentTime) {
+		return new AsyncMarker(manager, sendingIndex, sendingDelta, System.currentTimeMillis(), timeoutDelta);
+	}
+	
+	@Override
+	public PacketStream getPacketStream() {
+		return manager;
+	}
+
+	@Override
+	public Logger getLogger() {
+		return logger;
+	}
+
+	@Override
+	public void cleanupAll() {
+		cleaningUp = true;
+		serverProcessingQueue.cleanupAll();
+		serverQueue.cleanupAll();
+	}
+
+	/**
+	 * Signal that a packet is ready to be transmitted.
+	 * @param packet - packet to signal.
+	 */
+	public void signalPacketUpdate(PacketEvent packet) {
+		getSendingQueue(packet).signalPacketUpdate(packet, onMainThread());
+	}
+
+	/**
+	 * Retrieve the sending queue this packet belongs to.
+	 * @param packet - the packet.
+	 * @return The server or client sending queue the packet belongs to.
+	 */
+	private PacketSendingQueue getSendingQueue(PacketEvent packet) {
+		return packet.isServerPacket() ? serverQueue : clientQueue;
+	}
+	
+	/**
+	 * Signal that a packet has finished processing.
+	 * @param packet - packet to signal.
+	 */
+	public void signalProcessingDone(PacketEvent packet) {
+		getProcessingQueue(packet).signalProcessingDone();
+	}
+	
+	/**
+	 * Retrieve the processing queue this packet belongs to.
+	 * @param packet - the packet.
+	 * @return The server or client sending processing the packet belongs to.
+	 */
+	private PacketProcessingQueue getProcessingQueue(PacketEvent packet) {
+		return packet.isServerPacket() ? serverProcessingQueue : clientProcessingQueue;
+	}
+
+	/**
+	 * Send any due packets, or clean up packets that have expired.
+	 */
+	public void sendProcessedPackets(int tickCounter, boolean onMainThread) {
+		
+		// The server queue is unlikely to need checking that often
+		if (tickCounter % 10 == 0) {
+			serverQueue.trySendPackets(onMainThread);
+		}
+
+		clientQueue.trySendPackets(onMainThread);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/async/AsyncListenerHandler.java

@@ -0,0 +1,210 @@
+package com.comphenix.protocol.async;
+
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.logging.Level;
+
+import org.bukkit.plugin.Plugin;
+
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.events.PacketListener;
+
+/**
+ * Represents a handler for an asynchronous event.
+ * 
+ * @author Kristian
+ */
+public class AsyncListenerHandler {
+
+	/**
+	 * Signal an end to the packet processing.
+	 */
+	private static final PacketEvent INTERUPT_PACKET = new PacketEvent(new Object());
+	
+	// Default queue capacity
+	private static int DEFAULT_CAPACITY = 1024;
+	
+	// Cancel the async handler
+	private volatile boolean cancelled;
+	
+	// If we've started the listener loop before
+	private volatile boolean started;
+	
+	// The packet listener
+	private PacketListener listener;
+
+	// The filter manager
+	private AsyncFilterManager filterManager;
+	private NullPacketListener nullPacketListener;
+	
+	// List of queued packets
+	private ArrayBlockingQueue<PacketEvent> queuedPackets = new ArrayBlockingQueue<PacketEvent>(DEFAULT_CAPACITY);
+
+	// Minecraft main thread
+	private Thread mainThread;
+	
+	public AsyncListenerHandler(Thread mainThread, AsyncFilterManager filterManager, PacketListener listener) {
+		if (filterManager == null)
+			throw new IllegalArgumentException("filterManager cannot be NULL");
+		if (listener == null)
+			throw new IllegalArgumentException("listener cannot be NULL");
+
+		this.mainThread = mainThread;
+		this.filterManager = filterManager;
+		this.listener = listener;
+	}
+	
+	public boolean isCancelled() {
+		return cancelled;
+	}
+
+	public PacketListener getAsyncListener() {
+		return listener;
+	}
+
+	/**
+	 * Set the synchronized listener that has been automatically created.
+	 * @param nullPacketListener - automatically created listener.
+	 */
+	void setNullPacketListener(NullPacketListener nullPacketListener) {
+		this.nullPacketListener = nullPacketListener;
+	}
+
+	/**
+	 * Retrieve the synchronized listener that was automatically created.
+	 * @return Automatically created listener.
+	 */
+	PacketListener getNullPacketListener() {
+		return nullPacketListener;
+	}
+	
+	/**
+	 * Cancel the handler.
+	 */
+	public void cancel() {
+		// Remove the listener as quickly as possible
+		close();
+		
+		// Poison Pill Shutdown
+		queuedPackets.clear();
+		queuedPackets.add(INTERUPT_PACKET);
+	}
+	
+	/**
+	 * Queue a packet for processing.
+	 * @param packet - a packet for processing.
+	 * @throws IllegalStateException If the underlying packet queue is full.
+	 */
+	public void enqueuePacket(PacketEvent packet) {
+		if (packet == null)
+			throw new IllegalArgumentException("packet is NULL");
+		
+		queuedPackets.add(packet);
+	}
+	
+	/**
+	 * Create a runnable that will initiate the listener loop.
+	 * <p>
+	 * <b>Warning</b>: Never call the run() method in the main thread.
+	 */
+	public Runnable getListenerLoop() {
+		return new Runnable() {
+			@Override
+			public void run() {
+				listenerLoop();
+			}
+		};
+	}
+	
+	// DO NOT call this method from the main thread
+	private void listenerLoop() {
+		
+		// Danger, danger!
+		if (Thread.currentThread().getId() == mainThread.getId()) 
+			throw new IllegalStateException("Do not call this method from the main thread.");
+		if (started) 
+			throw new IllegalStateException("A listener cannot be run by multiple threads. Create a new listener instead.");
+		if (cancelled)
+			throw new IllegalStateException("Listener has been cancelled. Create a new listener instead.");
+		
+		// Proceed
+		started = true;
+		
+		try {
+			mainLoop:
+			while (!cancelled) {
+				PacketEvent packet = queuedPackets.take();
+				AsyncMarker marker = packet.getAsyncMarker();
+				
+				// Handle cancel requests
+				if (packet == null || marker == null || !packet.isAsynchronous()) {
+					break;
+				}
+				
+				// Here's the core of the asynchronous processing
+				try {
+					if (packet.isServerPacket())
+						listener.onPacketSending(packet);
+					else
+						listener.onPacketReceiving(packet);
+					
+				} catch (Throwable e) {
+					// Minecraft doesn't want your Exception.
+					filterManager.getLogger().log(Level.SEVERE, 
+							"Unhandled exception occured in onAsyncPacket() for " + getPluginName(), e);
+				}
+				
+				// Now, get the next non-cancelled listener
+				for (; marker.getListenerTraversal().hasNext(); ) {
+					AsyncListenerHandler handler = marker.getListenerTraversal().next().getListener();
+					
+					if (!handler.isCancelled()) {
+						handler.enqueuePacket(packet);
+						continue mainLoop;
+					}
+				}
+				
+				// There are no more listeners - queue the packet for transmission
+				filterManager.signalPacketUpdate(packet);
+				filterManager.signalProcessingDone(packet);
+			}
+			
+		} catch (InterruptedException e) {
+			// We're done
+		}
+		
+		// Clean up
+		close();
+	}
+	
+	private void close() {
+		// Remove the listener itself
+		if (!cancelled) {
+			filterManager.unregisterAsyncHandlerInternal(this);
+			cancelled = true;
+			started = false;
+		}
+	}
+	
+	private String getPluginName() {
+		return PacketAdapter.getPluginName(listener);
+	}
+
+	/**
+	 * Retrieve the plugin associated with this async listener.
+	 * @return The plugin.
+	 */
+	public Plugin getPlugin() {
+		return listener != null ? listener.getPlugin() : null;
+	}
+
+	/**
+	 * Start the asynchronous listener using the Bukkit scheduler.
+	 */
+	public void start() {
+		if (listener.getPlugin() == null)
+			throw new IllegalArgumentException("Cannot start task without a valid plugin.");
+		
+		filterManager.scheduleAsyncTask(listener.getPlugin(), getListenerLoop());
+	}
+}

ProtocolLib/src/com/comphenix/protocol/async/AsyncMarker.java

@@ -0,0 +1,303 @@
+package com.comphenix.protocol.async;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Iterator;
+import java.util.List;
+
+import net.minecraft.server.Packet;
+
+import com.comphenix.protocol.PacketStream;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.injector.PrioritizedListener;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.google.common.primitives.Longs;
+
+/**
+ * Contains information about the packet that is being processed by asynchronous listeners.
+ * 
+ * @author Kristian
+ */
+public class AsyncMarker implements Serializable, Comparable<AsyncMarker> {
+		
+	/**
+	 * Generated by Eclipse.
+	 */
+	private static final long serialVersionUID = -2621498096616187384L;
+
+	/**
+	 * Default number of milliseconds until a packet will rejected.
+	 */
+	public static final int DEFAULT_TIMEOUT_DELTA = 60000;
+	
+	/**
+	 * Default number of packets to skip.
+	 */
+	public static final int DEFAULT_SENDING_DELTA = 0;
+	
+	/**
+	 * The packet stream responsible for transmitting the packet when it's done processing.
+	 */
+	private transient PacketStream packetStream;
+	
+	/**
+	 * Current list of async packet listeners.
+	 */
+	private transient Iterator<PrioritizedListener<AsyncListenerHandler>> listenerTraversal;
+	
+	// Timeout handling
+	private long initialTime;
+	private long timeout;
+	
+	// Packet order
+	private long originalSendingIndex;
+	private long newSendingIndex;
+	
+	// Whether or not the packet has been processed by the listeners
+	private volatile boolean processed;
+	
+	// Whether or not the packet has been sent
+	private volatile boolean transmitted;
+	
+	// Whether or not the asynchronous processing itself should be cancelled
+	private volatile boolean asyncCancelled;
+	
+	// Determine if Minecraft processes this packet asynchronously
+	private static Method isMinecraftAsync;
+	private static boolean alwaysSync;
+
+	/**
+	 * Create a container for asyncronous packets.
+	 * @param initialTime - the current time in milliseconds since 01.01.1970 00:00.
+	 */
+	AsyncMarker(PacketStream packetStream, long sendingIndex, long sendingDelta, long initialTime, long timeoutDelta) {
+		if (packetStream == null)
+			throw new IllegalArgumentException("packetStream cannot be NULL");
+		
+		this.packetStream = packetStream;
+		
+		// Timeout
+		this.initialTime = initialTime;
+		this.timeout = initialTime + timeoutDelta;
+		
+		// Sending index
+		this.originalSendingIndex = sendingIndex;
+		this.newSendingIndex = sendingIndex;
+	}
+	
+	/**
+	 * Retrieve the time the packet was initially queued for asynchronous processing.
+	 * @return The initial time in number of milliseconds since 01.01.1970 00:00. 
+	 */
+	public long getInitialTime() {
+		return initialTime;
+	}	
+
+	/**
+	 * Retrieve the time the packet will be forcefully rejected.
+	 * @return The time to reject the packet, in milliseconds since 01.01.1970 00:00.
+	 */
+	public long getTimeout() {
+		return timeout;
+	}
+	
+	/**
+	 * Set the time the packet will be forcefully rejected.
+	 * @param timeout - time to reject the packet, in milliseconds since 01.01.1970 00:00.
+	 */
+	public void setTimeout(long timeout) {
+		this.timeout = timeout;
+	}
+
+	/**
+	 * Retrieve the order the packet was originally transmitted.
+	 * @return The original packet index.
+	 */
+	public long getOriginalSendingIndex() {
+		return originalSendingIndex;
+	}
+
+	/**
+	 * Retrieve the desired sending order after processing has completed.
+	 * <p>
+	 * Higher sending order means lower priority.
+	 * @return Desired sending order.
+	 */
+	public long getNewSendingIndex() {
+		return newSendingIndex;
+	}
+
+	/**
+	 * Sets the desired sending order after processing has completed.
+	 * <p>
+	 * Higher sending order means lower priority.
+	 * @param newSendingIndex - new packet send index.
+	 */
+	public void setNewSendingIndex(long newSendingIndex) {
+		this.newSendingIndex = newSendingIndex;
+	}
+
+	/**
+	 * Retrieve the packet stream responsible for transmitting this packet.
+	 * @return The packet stream.
+	 */
+	public PacketStream getPacketStream() {
+		return packetStream;
+	}
+
+	/**
+	 * Sets the output packet stream responsible for transmitting this packet.
+	 * @param packetStream - new output packet stream.
+	 */
+	public void setPacketStream(PacketStream packetStream) {
+		this.packetStream = packetStream;
+	}
+
+	/**
+	 * Retrieve whether or not this packet has been processed by the async listeners.
+	 * @return TRUE if it has been processed, FALSE otherwise.
+	 */
+	public boolean isProcessed() {
+		return processed;
+	}
+
+	/**
+	 * Sets whether or not this packet has been processed by the async listeners.
+	 * @param processed - TRUE if it has, FALSE otherwise.
+	 */
+	void setProcessed(boolean processed) {
+		this.processed = processed;
+	}
+
+	/**
+	 * Retrieve whether or not this packet has already been sent.
+	 * @return TRUE if it has been sent before, FALSE otherwise.
+	 */
+	public boolean isTransmitted() {
+		return transmitted;
+	}
+
+	/**
+	 * Determine if this packet has expired.
+	 * @return TRUE if it has, FALSE otherwise.
+	 */
+	public boolean hasExpired() {
+		return hasExpired(System.currentTimeMillis());
+	}
+	
+	/**
+	 * Determine if this packet has expired given this time.
+	 * @param currentTime - the current time in milliseconds since 01.01.1970 00:00.
+	 * @return TRUE if it has, FALSE otherwise.
+	 */
+	public boolean hasExpired(long currentTime) {
+		return timeout < currentTime;
+	}
+	
+	/**
+	 * Determine if the asynchronous handling should be cancelled.
+	 * @return TRUE if it should, FALSE otherwise.
+	 */
+	public boolean isAsyncCancelled() {
+		return asyncCancelled;
+	}
+
+	/**
+	 * Set whether or not the asynchronous handling should be cancelled.
+	 * @param asyncCancelled - TRUE to cancel it, FALSE otherwise.
+	 */
+	public void setAsyncCancelled(boolean asyncCancelled) {
+		this.asyncCancelled = asyncCancelled;
+	}
+	
+	/**
+	 * Retrieve iterator for the next listener in line.
+	 * @return Next async packet listener iterator.
+	 */
+	public Iterator<PrioritizedListener<AsyncListenerHandler>> getListenerTraversal() {
+		return listenerTraversal;
+	}
+	
+	/**
+	 * Set the iterator for the next listener.
+	 * @param listenerTraversal - the new async packet listener iterator.
+	 */
+	void setListenerTraversal(Iterator<PrioritizedListener<AsyncListenerHandler>> listenerTraversal) {
+		this.listenerTraversal = listenerTraversal;
+	}
+	
+	/**
+	 * Transmit a given packet to the current packet stream.
+	 * @param event - the packet to send.
+	 * @throws IOException If the packet couldn't be sent.
+	 */
+	public void sendPacket(PacketEvent event) throws IOException {
+		try {
+			if (event.isServerPacket()) {
+				packetStream.sendServerPacket(event.getPlayer(), event.getPacket(), false);
+			} else {
+				packetStream.recieveClientPacket(event.getPlayer(), event.getPacket(), false);
+			}
+			transmitted = true;
+			
+		} catch (InvocationTargetException e) {
+			throw new IOException("Cannot send packet", e);
+		} catch (IllegalAccessException e) {
+			throw new IOException("Cannot send packet", e);
+		}
+	}
+	
+	/**
+	 * Determine if Minecraft allows asynchronous processing of this packet.
+	 * @return TRUE if it does, FALSE otherwise.
+	 */
+	public boolean isMinecraftAsync(PacketEvent event) throws FieldAccessException {
+		
+		if (isMinecraftAsync == null && !alwaysSync) {
+			try {
+				isMinecraftAsync = FuzzyReflection.fromClass(Packet.class).getMethodByName("a_.*");
+			} catch (RuntimeException e) {
+				// This will occur in 1.2.5 (or possibly in later versions)
+				List<Method> methods = FuzzyReflection.fromClass(Packet.class).
+										getMethodListByParameters(boolean.class, new Class[] {});
+				
+				// Try to look for boolean methods
+				if (methods.size() == 2) {
+					isMinecraftAsync = methods.get(1);
+				} else if (methods.size() == 1) {
+					// We're in 1.2.5
+					alwaysSync = true;
+				} else {
+					System.err.println("Cannot determine asynchronous state of packets!");
+					alwaysSync = true;
+				}
+			}
+		}
+		
+		if (alwaysSync) {
+			return false;
+		} else {
+			try {
+				// Wrap exceptions 
+				return (Boolean) isMinecraftAsync.invoke(event.getPacket().getHandle());
+			} catch (IllegalArgumentException e) {
+				throw new FieldAccessException("Illegal argument", e);
+			} catch (IllegalAccessException e) {
+				throw new FieldAccessException("Unable to reflect method call 'a_', or: isAsyncPacket.", e);
+			} catch (InvocationTargetException e) {
+				throw new FieldAccessException("Minecraft error", e);
+			}
+		}
+	}
+	
+	@Override
+	public int compareTo(AsyncMarker o) {
+		if (o == null)
+			return 1;
+		else
+			return Longs.compare(getNewSendingIndex(), o.getNewSendingIndex());
+	}
+}

ProtocolLib/src/com/comphenix/protocol/async/NullPacketListener.java

@@ -0,0 +1,62 @@
+package com.comphenix.protocol.async;
+
+import org.bukkit.plugin.Plugin;
+
+import com.comphenix.protocol.events.ListenerPriority;
+import com.comphenix.protocol.events.ListeningWhitelist;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.events.PacketListener;
+
+/**
+ * Represents a NO OPERATION listener.
+ * 
+ * @author Kristian
+ */
+class NullPacketListener implements PacketListener {
+	
+	private ListeningWhitelist sendingWhitelist;
+	private ListeningWhitelist receivingWhitelist;
+	private Plugin plugin;
+
+	/**
+	 * Create a no-op listener with the same whitelist and plugin as the given listener.
+	 * @param original - the packet listener to copy.
+	 */
+	public NullPacketListener(PacketListener original) {
+		this.sendingWhitelist = cloneWhitelist(ListenerPriority.LOW, original.getSendingWhitelist());
+		this.receivingWhitelist = cloneWhitelist(ListenerPriority.LOW, original.getReceivingWhitelist());
+		this.plugin = original.getPlugin();
+	}
+
+	@Override
+	public void onPacketSending(PacketEvent event) {
+		// NULL
+	}
+
+	@Override
+	public void onPacketReceiving(PacketEvent event) {
+		// NULL
+	}
+
+	@Override
+	public ListeningWhitelist getSendingWhitelist() {
+		return sendingWhitelist;
+	}
+
+	@Override
+	public ListeningWhitelist getReceivingWhitelist() {
+		return receivingWhitelist;
+	}
+	
+	private ListeningWhitelist cloneWhitelist(ListenerPriority priority, ListeningWhitelist whitelist) {
+		if (whitelist != null) 
+			return new ListeningWhitelist(priority, whitelist.getWhitelist());
+		else 
+			return null;
+	}
+
+	@Override
+	public Plugin getPlugin() {
+		return plugin;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/async/PacketProcessingQueue.java

@@ -0,0 +1,133 @@
+package com.comphenix.protocol.async;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.Semaphore;
+
+import com.comphenix.protocol.concurrency.AbstractConcurrentListenerMultimap;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.injector.PrioritizedListener;
+
+/**
+ * Handles the processing of every packet type.
+ * 
+ * @author Kristian
+ */
+class PacketProcessingQueue extends AbstractConcurrentListenerMultimap<AsyncListenerHandler> {
+
+	/**
+	 * Default maximum number of packets to process concurrently.
+	 */
+	public static final int DEFAULT_MAXIMUM_CONCURRENCY = 32;
+	
+	/**
+	 * Default maximum number of packets to queue for processing.
+	 */
+	public static final int DEFAULT_QUEUE_LIMIT = 1024 * 60;
+	
+	/**
+	 * Number of packets we're processing concurrently.
+	 */
+	private final int maximumConcurrency;
+	private Semaphore concurrentProcessing;
+	
+	// Queued packets for being processed
+	private ArrayBlockingQueue<PacketEvent> processingQueue;
+	
+	// Packets for sending
+	private PacketSendingQueue sendingQueue;
+
+	public PacketProcessingQueue(PacketSendingQueue sendingQueue) {
+		this(sendingQueue, DEFAULT_QUEUE_LIMIT, DEFAULT_MAXIMUM_CONCURRENCY);
+	}
+	
+	public PacketProcessingQueue(PacketSendingQueue sendingQueue, int queueLimit, int maximumConcurrency) {
+		super();
+		this.processingQueue = new ArrayBlockingQueue<PacketEvent>(queueLimit);
+		this.maximumConcurrency = maximumConcurrency;
+		this.concurrentProcessing = new Semaphore(maximumConcurrency);
+		this.sendingQueue = sendingQueue;
+	}
+	
+	/**
+	 * Enqueue a packet for processing by the asynchronous listeners.
+	 * @param packet - packet to process.
+	 * @param onMainThread - whether or not this is occuring on the main thread.
+	 * @return TRUE if we sucessfully queued the packet, FALSE if the queue ran out if space.
+	 */
+	public boolean enqueue(PacketEvent packet, boolean onMainThread) {
+		try {
+			processingQueue.add(packet);
+			
+			// Begin processing packets
+			signalBeginProcessing(onMainThread);
+			return true;
+		} catch (IllegalStateException e) {
+			return false;
+		}
+	}
+	
+	/**
+	 * Called by the current method and each thread to signal that a packet might be ready for processing.
+	 * @param onMainThread - whether or not this is occuring on the main thread.
+	 */
+	public void signalBeginProcessing(boolean onMainThread) {	
+		while (concurrentProcessing.tryAcquire()) {
+			PacketEvent packet = processingQueue.poll();
+			
+			// Any packet queued?
+			if (packet != null) {
+				Collection<PrioritizedListener<AsyncListenerHandler>> list = getListener(packet.getPacketID());
+				AsyncMarker marker = packet.getAsyncMarker();
+				
+				// Yes, removing the marker will cause the chain to stop
+				if (list != null) {
+					Iterator<PrioritizedListener<AsyncListenerHandler>> iterator = list.iterator();
+					
+					if (iterator.hasNext()) {
+						marker.setListenerTraversal(iterator);
+						iterator.next().getListener().enqueuePacket(packet);
+						continue;
+					}
+				}
+				
+				// The packet has no further listeners. Just send it.
+				sendingQueue.signalPacketUpdate(packet, onMainThread);
+				signalProcessingDone();
+				
+			} else {
+				// No more queued packets.
+				signalProcessingDone();
+				return;
+			}
+ 		}
+	}
+	
+	/**
+	 * Called when a packet has been processed.
+	 */
+	public void signalProcessingDone() {
+		concurrentProcessing.release();
+	}
+
+	/**
+	 * Retrieve the maximum number of packets to process at any given time.
+	 * @return Number of simultaneous packet to process.
+	 */
+	public int getMaximumConcurrency() {
+		return maximumConcurrency;
+	}
+	
+	public void cleanupAll() {
+		// Cancel all the threads and every listener
+		for (PrioritizedListener<AsyncListenerHandler> handler : values()) {
+			if (handler != null) {
+				handler.getListener().cancel();
+			}
+		}
+		
+		// Remove the rest, just in case
+		clearListeners();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/async/PacketSendingQueue.java

@@ -0,0 +1,177 @@
+package com.comphenix.protocol.async;
+
+import java.io.IOException;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.PriorityBlockingQueue;
+
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.google.common.collect.ComparisonChain;
+
+/**
+ * Represents packets ready to be transmitted to a client.
+ * @author Kristian
+ */
+class PacketSendingQueue {
+
+	private static final int INITIAL_CAPACITY = 64;
+	
+	private PriorityBlockingQueue<PacketEvent> sendingQueue;
+	
+	// Whether or not packet transmission can only occur on the main thread
+	private final boolean synchronizeMain;
+	
+	/**
+	 * Create a packet sending queue.
+	 * @param synchronizeMain - whether or not to synchronize with the main thread.
+	 */
+	public PacketSendingQueue(boolean synchronizeMain) {
+		this.synchronizeMain = synchronizeMain;
+		this.sendingQueue = new PriorityBlockingQueue<PacketEvent>(INITIAL_CAPACITY, new Comparator<PacketEvent>() {
+			// Compare using the async marker
+			@Override
+			public int compare(PacketEvent o1, PacketEvent o2) {
+				return ComparisonChain.start().
+					   compare(o1.getAsyncMarker(), o2.getAsyncMarker()).
+					   result();
+			}
+		});
+	}
+	
+	/**
+	 * Enqueue a packet for sending. 
+	 * @param packet
+	 */
+	public void enqueue(PacketEvent packet) {
+		sendingQueue.add(packet);
+	}
+	
+	/**
+	 * Invoked when one of the packets have finished processing.
+	 * @param packetUpdated - the packet that has now been updated.
+	 * @param onMainThread - whether or not this is occuring on the main thread.
+	 */
+	public synchronized void signalPacketUpdate(PacketEvent packetUpdated, boolean onMainThread) {
+		// Mark this packet as finished
+		packetUpdated.getAsyncMarker().setProcessed(true);
+		trySendPackets(onMainThread);
+	}
+
+	/***
+	 * Invoked when a list of packet IDs are no longer associated with any listeners.
+	 * @param packetsRemoved - packets that no longer have any listeners.
+	 * @param onMainThread - whether or not this is occuring on the main thread.
+	 */
+	public synchronized void signalPacketUpdate(List<Integer> packetsRemoved, boolean onMainThread) {
+		
+		Set<Integer> lookup = new HashSet<Integer>(packetsRemoved);
+		
+		// Note that this is O(n), so it might be expensive
+		for (PacketEvent event : sendingQueue) {
+			if (lookup.contains(event.getPacketID())) {
+				event.getAsyncMarker().setProcessed(true);
+			}
+		}
+		
+		// This is likely to have changed the situation a bit
+		trySendPackets(onMainThread);
+	}
+	
+	/**
+	 * Attempt to send any remaining packets.
+	 * @param onMainThread - whether or not this is occuring on the main thread.
+	 */
+	public void trySendPackets(boolean onMainThread) {
+				
+		// Transmit as many packets as we can
+		while (true) {
+			PacketEvent current = sendingQueue.peek();
+					
+			if (current != null) {
+				AsyncMarker marker = current.getAsyncMarker();
+				
+				// Abort if we're not on the main thread
+				if (synchronizeMain) {
+					try {
+						boolean wantAsync = marker.isMinecraftAsync(current);
+						boolean wantSync = !wantAsync;
+						
+						// Quit if we haven't fulfilled our promise
+						if ((onMainThread && wantAsync) || (!onMainThread && wantSync))
+							return;
+						
+					} catch (FieldAccessException e) {
+						e.printStackTrace();
+						return;
+					}
+				}
+				
+				if (marker.isProcessed() || marker.hasExpired()) {
+					if (marker.isProcessed() && !current.isCancelled()) {
+						sendPacket(current);
+					}
+					
+					sendingQueue.poll();
+					continue;
+				}
+			}
+			
+			// Only repeat when packets are removed
+			break;
+		}
+	}
+	
+	/**
+	 * Send every packet, regardless of the processing state.
+	 */
+	private void forceSend() {
+		while (true) {
+			PacketEvent current = sendingQueue.poll();
+			
+			if (current != null) {
+				sendPacket(current);
+			} else {
+				break;
+			}
+		}
+	}
+	
+	/**
+	 * Whether or not the packet transmission must synchronize with the main thread.
+	 * @return TRUE if it must, FALSE otherwise.
+	 */
+	public boolean isSynchronizeMain() {
+		return synchronizeMain;
+	}
+
+	/**
+	 * Transmit a packet, if it hasn't already.
+	 * @param event - the packet to transmit.
+	 */
+	private void sendPacket(PacketEvent event) {
+		
+		AsyncMarker marker = event.getAsyncMarker();
+		
+		try {
+			// Don't send a packet twice
+			if (marker != null && !marker.isTransmitted()) {
+				marker.sendPacket(event);
+			}
+			
+		} catch (IOException e) {
+			// Just print the error
+			e.printStackTrace();
+		}
+	}
+
+	/**
+	 * Automatically transmits every delayed packet.
+	 */
+	public void cleanupAll() {
+		// Note that the cleanup itself will always occur on the main thread
+		forceSend();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/concurrency/AbstractConcurrentListenerMultimap.java

@@ -0,0 +1,131 @@
+package com.comphenix.protocol.concurrency;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import com.comphenix.protocol.events.ListeningWhitelist;
+import com.comphenix.protocol.injector.PrioritizedListener;
+import com.google.common.collect.Iterables;
+
+/**
+ * A thread-safe implementation of a listener multimap.
+ * 
+ * @author Kristian
+ */
+public abstract class AbstractConcurrentListenerMultimap<TListener> {
+
+	// The core of our map
+	private ConcurrentMap<Integer, SortedCopyOnWriteArray<PrioritizedListener<TListener>>> listeners = 
+		new ConcurrentHashMap<Integer, SortedCopyOnWriteArray<PrioritizedListener<TListener>>>();
+	
+	/**
+	 * Adds a listener to its requested list of packet recievers.
+	 * @param listener - listener with a list of packets to recieve notifcations for.
+	 * @param whitelist - the packet whitelist to use.
+	 */
+	public void addListener(TListener listener, ListeningWhitelist whitelist) {
+		
+		PrioritizedListener<TListener> prioritized = new PrioritizedListener<TListener>(listener, whitelist.getPriority());
+		
+		for (Integer packetID : whitelist.getWhitelist()) {
+			addListener(packetID, prioritized);
+		}
+	}
+	
+	// Add the listener to a specific packet notifcation list
+	private void addListener(Integer packetID, PrioritizedListener<TListener> listener) {
+		
+		SortedCopyOnWriteArray<PrioritizedListener<TListener>> list = listeners.get(packetID);
+		
+		// We don't want to create this for every lookup
+		if (list == null) {
+			// It would be nice if we could use a PriorityBlockingQueue, but it doesn't preseve iterator order,
+			// which is a essential feature for our purposes.
+			final SortedCopyOnWriteArray<PrioritizedListener<TListener>> value = new SortedCopyOnWriteArray<PrioritizedListener<TListener>>();
+			
+			list = listeners.putIfAbsent(packetID, value);
+			
+			// We may end up creating multiple multisets, but we'll agree 
+			// on the one to use.
+			if (list == null) {
+				list = value;
+			}
+		}
+		
+		// Thread safe
+		list.add(listener);
+	}
+	
+	/**
+	 * Removes the given listener from the packet event list.
+	 * @param listener - listener to remove.
+	 * @param whitelist - the packet whitelist that was used.
+	 * @return Every packet ID that was removed due to no listeners.
+	 */
+	public List<Integer> removeListener(TListener listener, ListeningWhitelist whitelist) {
+	
+		List<Integer> removedPackets = new ArrayList<Integer>();
+		
+		// Again, not terribly efficient. But adding or removing listeners should be a rare event.
+		for (Integer packetID : whitelist.getWhitelist()) {
+			
+			SortedCopyOnWriteArray<PrioritizedListener<TListener>> list = listeners.get(packetID);
+			
+			// Remove any listeners
+			if (list != null) {
+				// Don't remove from newly created lists
+				if (list.size() > 0) {
+					// Remove this listener. Note that priority is generally ignored.
+					list.remove(new PrioritizedListener<TListener>(listener, whitelist.getPriority()));
+					
+					if (list.size() == 0) {
+						listeners.remove(packetID);
+						removedPackets.add(packetID);
+					}
+				}
+			}
+			
+			// Move on to the next
+		}
+		
+		return removedPackets;
+	}
+	
+	/**
+	 * Retrieve the registered listeners, in order from the lowest to the highest priority.
+	 * <p>
+	 * The returned list is thread-safe and doesn't require synchronization.
+	 * @param packetID - packet ID.
+	 * @return Registered listeners.
+	 */
+	public Collection<PrioritizedListener<TListener>> getListener(int packetID) {
+		return listeners.get(packetID);
+	}
+	
+	/**
+	 * Retrieve every listener.
+	 * @return Every listener.
+	 */
+	public Iterable<PrioritizedListener<TListener>> values() {
+		return Iterables.concat(listeners.values());
+	}
+	
+	/**
+	 * Retrieve every registered packet ID:
+	 * @return Registered packet ID.
+	 */
+	public Set<Integer> keySet() {
+		return listeners.keySet();
+	}
+	
+	/**
+	 * Remove all packet listeners.
+	 */
+	protected void clearListeners() {
+		listeners.clear();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/concurrency/SortedCopyOnWriteArray.java

@@ -0,0 +1,223 @@
+package com.comphenix.protocol.concurrency;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import com.google.common.base.Objects;
+import com.google.common.collect.Iterables;
+
+/**
+ * An implicitly sorted array list that preserves insertion order and maintains duplicates.
+ * @param <T> - type of the elements in the list.
+ */
+public class SortedCopyOnWriteArray<T extends Comparable<T>> implements Iterable<T>, Collection<T> {
+	// Prevent reordering
+	private volatile List<T> list;
+	
+	/**
+	 * Construct an empty sorted array.
+	 */
+	public SortedCopyOnWriteArray() {
+		list = new ArrayList<T>();
+	}
+	
+	/**
+	 * Create a sorted array from the given list. The elements will be automatically sorted.
+	 * @param wrapped - the collection whose elements are to be placed into the list.
+	 */
+	public SortedCopyOnWriteArray(Collection<T> wrapped) {
+		this.list = new ArrayList<T>(wrapped);
+	}
+	
+	/**
+	 * Create a sorted array from the given list. 
+	 * @param wrapped - the collection whose elements are to be placed into the list.
+	 * @param sort - TRUE to automatically sort the collection, FALSE if it is already sorted. 
+	 */
+	public SortedCopyOnWriteArray(Collection<T> wrapped, boolean sort) {
+		this.list = new ArrayList<T>(wrapped);
+		
+		if (sort) {
+			Collections.sort(list);
+		}
+	}
+	
+	/**
+	 * Inserts the given element in the proper location.
+	 * @param value - element to insert.
+	 */
+	@Override
+	public synchronized boolean add(T value) {
+    	
+    	// We use NULL as a special marker, so we don't allow it
+    	if (value == null)
+    		throw new IllegalArgumentException("value cannot be NULL");
+    	
+    	List<T> copy = new ArrayList<T>();
+
+        for (T element : list) {
+        	// If the value is now greater than the current element, it should be placed right before it
+        	if (value != null && value.compareTo(element) < 0) {
+        		copy.add(value);
+        		value = null;
+        	}
+        	copy.add(element);
+        }
+        
+        // Don't forget to add it
+        if (value != null)
+        	copy.add(value);
+        
+        list = copy;
+        return true;
+    }
+    
+	@Override
+    public synchronized boolean addAll(Collection<? extends T> values) {
+		
+		if (values == null)
+			throw new IllegalArgumentException("values cannot be NULL");
+		if (values.size() == 0)
+			return false;
+		
+    	List<T> copy = new ArrayList<T>();
+    	
+    	// Insert the new content and sort it
+    	copy.addAll(list);
+    	copy.addAll(values);
+    	Collections.sort(copy);
+    	
+    	list = copy;
+    	return true;
+    }
+    
+    /**
+     * Removes from the list by making a new list with every element except the one given.
+     * <p>
+     * Objects will be compared using the given objects equals() method.
+     * @param value - value to remove.
+     */
+	@Override
+    public synchronized boolean remove(Object value) {
+    	List<T> copy = new ArrayList<T>();
+    	
+    	// Note that there's not much to be gained from using BinarySearch, as we
+    	// have to copy (and thus read) the entire list regardless.
+    	
+    	// Copy every element except the one given to us. 
+    	for (T element : list) {
+    		if (value != null && !Objects.equal(value, element)) {
+    			copy.add(element);
+    			value = null;
+    		}
+    	}
+
+    	list = copy;
+    	return value == null;
+    }
+    
+	@Override
+	public boolean removeAll(Collection<?> values) {
+		// Special cases
+		if (values == null)
+			throw new IllegalArgumentException("values cannot be NULL");
+		if (values.size() == 0)
+			return false;
+		
+		List<T> copy = new ArrayList<T>();
+		
+		copy.addAll(list);
+		copy.removeAll(values);
+		
+		list = copy;
+		return true;
+	}
+
+	@Override
+	public boolean retainAll(Collection<?> values) {
+		// Special cases
+		if (values == null)
+			throw new IllegalArgumentException("values cannot be NULL");
+		if (values.size() == 0)
+			return false;
+		
+		List<T> copy = new ArrayList<T>();
+		
+		copy.addAll(list);
+		copy.removeAll(values);
+		
+		list = copy;
+		return true;
+	}
+	
+    /**
+     * Removes from the list by making a copy of every element except the one with the given index.
+     * @param index - index of the element to remove.
+     */
+    public synchronized void remove(int index) {
+    	
+    	List<T> copy = new ArrayList<T>(list);
+    	
+    	copy.remove(index);
+    	list = copy;
+    }
+    
+    /**
+     * Retrieves an element by index. 
+     * @param index - index of element to retrieve.
+     * @return The element at the given location.
+     */
+    public T get(int index) {
+    	return list.get(index);
+    }
+    
+    /**
+     * Retrieve the size of the list.
+     * @return Size of the list.
+     */
+    public int size() {
+    	return list.size();
+    }
+
+    /**
+     * Retrieves an iterator over the elements in the given list. 
+     * Warning: No not attempt to remove elements using the iterator.
+     */
+	public Iterator<T> iterator() {
+		return Iterables.unmodifiableIterable(list).iterator();
+	}
+	
+	@Override
+	public void clear() {
+		list = new ArrayList<T>();
+	}
+
+	@Override
+	public boolean contains(Object value) {
+		return list.contains(value);
+	}
+
+	@Override
+	public boolean containsAll(Collection<?> values) {
+		return list.containsAll(values);
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return list.isEmpty();
+	}
+
+	@Override
+	public Object[] toArray() {
+		return list.toArray();
+	}
+
+	@SuppressWarnings("hiding")
+	@Override
+	public <T> T[] toArray(T[] a) {
+		return list.toArray(a);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/events/ConnectionSide.java

@@ -1,3 +1,20 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.events;
 
 /**

ProtocolLib/src/com/comphenix/protocol/events/ListenerPriority.java

@@ -0,0 +1,68 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.protocol.events;
+
+/**
+ * Represents a packet event priority, similar to the Bukkit EventPriority.
+ * 
+ * @author Kristian
+ */
+public enum ListenerPriority {
+	/**
+	 * Event call is of very low importance and should be ran first, to allow
+	 * other plugins to further customise the outcome.
+	 */
+	LOWEST(0),
+	/**
+	 * Event call is of low importance.
+	 */
+	LOW(1),
+	/**
+	 * Event call is neither important or unimportant, and may be ran normally.
+	 */
+	NORMAL(2),
+	/**
+	 * Event call is of high importance.
+	 */
+	HIGH(3),
+	/**
+	 * Event call is critical and must have the final say in what happens to the
+	 * event.
+	 */
+	HIGHEST(4),
+	/**
+	 * Event is listened to purely for monitoring the outcome of an event.
+	 * <p/>
+	 * No modifications to the event should be made under this priority.
+	 */
+	MONITOR(5);
+
+	private final int slot;
+
+	private ListenerPriority(int slot) {
+		this.slot = slot;
+	}
+
+	/**
+	 * A low slot represents a low priority.
+	 * @return Integer representation of this priorty.
+	 */
+	public int getSlot() {
+		return slot;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/events/ListeningWhitelist.java

@@ -0,0 +1,127 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.protocol.events;
+
+import java.util.Set;
+
+import com.google.common.base.Objects;
+import com.google.common.collect.Sets;
+
+/**
+ * Determines which packets will be observed by a listener, and with what priority.
+
+ * @author Kristian 
+ */
+public class ListeningWhitelist {
+
+	/**
+	 * A whitelist with no packets - indicates that the listener shouldn't observe any packets.
+	 */
+	public static ListeningWhitelist EMPTY_WHITELIST = new ListeningWhitelist(ListenerPriority.LOW);
+	
+	private ListenerPriority priority;
+	private Set<Integer> whitelist;
+
+	/**
+	 * Creates a packet whitelist for a given priority with a set of packet IDs.
+	 * @param priority - the listener priority.
+	 * @param whitelist - set of IDs to observe/enable. 
+	 */
+	public ListeningWhitelist(ListenerPriority priority, Set<Integer> whitelist) {
+		this.priority = priority;
+		this.whitelist = whitelist;
+	}
+	
+	/**
+	 * Creates a packet whitelist of a given priority for a list of packets.
+	 * @param priority - the listener priority.
+	 * @param whitelist - list of packet IDs to observe/enable.
+	 */
+	public ListeningWhitelist(ListenerPriority priority, Integer... whitelist) {
+		this.priority = priority;
+		this.whitelist = Sets.newHashSet(whitelist);
+	}
+	
+	/**
+	 * Whether or not this whitelist has any enabled packets.
+	 * @return TRUE if there are any packets, FALSE otherwise.
+	 */
+	public boolean isEnabled() {
+		return whitelist != null && whitelist.size() > 0;
+	}
+	
+	/**
+	 * Retrieve the priority in the execution order of the packet listener. Highest priority will be executed last.
+	 * @return Execution order in terms of priority.
+	 */
+	public ListenerPriority getPriority() {
+		return priority;
+	}
+	
+	/**
+	 * Retrieves the list of packets that will be observed by the listeners.
+	 * @return Packet whitelist.
+	 */
+	public Set<Integer> getWhitelist() {
+		return whitelist;
+	}
+	
+	@Override
+	public int hashCode(){
+	    return Objects.hashCode(priority, whitelist);
+	}
+
+	/**
+	 * Determine if any of the given IDs can be found in the whitelist.
+	 * @param whitelist - whitelist to test.
+	 * @param idList - list of packet IDs to find. 
+	 * @return TRUE if any of the packets in the list can be found in the whitelist, FALSE otherwise.
+	 */
+	public static boolean containsAny(ListeningWhitelist whitelist, int... idList) {
+		if (whitelist != null) {
+			for (int i = 0; i < idList.length; i++) {
+				if (whitelist.getWhitelist().contains(idList[i]))
+					return true;
+			}
+		}
+		
+		return false;
+	}
+	
+	@Override
+	public boolean equals(final Object obj){
+	    if(obj instanceof ListeningWhitelist){
+	        final ListeningWhitelist other = (ListeningWhitelist) obj;
+	        return Objects.equal(priority, other.priority)
+	            && Objects.equal(whitelist, other.whitelist);
+	    } else{
+	        return false;
+	    }
+	}
+	
+	@Override
+	public String toString() {
+		if (this == EMPTY_WHITELIST)
+			return "EMPTY_WHITELIST";
+		else
+			return Objects.toStringHelper(this)
+				.add("priority", priority)
+				.add("packets", whitelist).toString();
+	}
+	
+}

ProtocolLib/src/com/comphenix/protocol/events/PacketAdapter.java

@@ -1,11 +1,23 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.events;
 
-import java.util.Set;
-
-import org.apache.commons.lang.StringUtils;
-import org.bukkit.plugin.java.JavaPlugin;
-
-import com.google.common.collect.Sets;
+import org.bukkit.plugin.Plugin;
 
 /**
  * Represents a packet listener with useful constructors.
@@ -14,20 +26,46 @@ import com.google.common.collect.Sets;
  */
 public abstract class PacketAdapter implements PacketListener {
 	
-	protected JavaPlugin plugin;
-	protected Set<Integer> packetsID;
+	protected Plugin plugin;
 	protected ConnectionSide connectionSide;
-	
+	protected ListeningWhitelist receivingWhitelist = ListeningWhitelist.EMPTY_WHITELIST;
+	protected ListeningWhitelist sendingWhitelist = ListeningWhitelist.EMPTY_WHITELIST;
+
 	/**
-	 * Initialize a packet listener.
+	 * Initialize a packet listener with default priority.
 	 * @param plugin - the plugin that spawned this listener.
 	 * @param connectionSide - the packet type the listener is looking for.
 	 * @param packets - the packet IDs the listener is looking for.
 	 */
-	public PacketAdapter(JavaPlugin plugin, ConnectionSide connectionSide, Integer... packets) {
+	public PacketAdapter(Plugin plugin, ConnectionSide connectionSide, Integer... packets) {
+		this(plugin, connectionSide, ListenerPriority.NORMAL, packets);
+	}
+	
+	/**
+	 * Initialize a packet listener for a single connection side.
+	 * @param plugin - the plugin that spawned this listener.
+	 * @param connectionSide - the packet type the listener is looking for.
+	 * @param listenerPriority - the event priority.
+	 * @param packets - the packet IDs the listener is looking for.
+	 */
+	public PacketAdapter(Plugin plugin, ConnectionSide connectionSide, ListenerPriority listenerPriority, Integer... packets) {
+		if (plugin == null)
+			throw new IllegalArgumentException("plugin cannot be null");
+		if (connectionSide == null)
+			throw new IllegalArgumentException("connectionSide cannot be null");
+		if (listenerPriority == null)
+			throw new IllegalArgumentException("listenerPriority cannot be null");
+		if (packets == null)
+			throw new IllegalArgumentException("packets cannot be null");
+		
+		// Add whitelists
+		if (connectionSide.isForServer())
+			sendingWhitelist = new ListeningWhitelist(listenerPriority, packets);
+		if (connectionSide.isForClient())
+			receivingWhitelist = new ListeningWhitelist(listenerPriority, packets);
+		
 		this.plugin = plugin;
 		this.connectionSide = connectionSide;
-		this.packetsID = Sets.newHashSet(packets);
 	}
 	
 	@Override
@@ -41,20 +79,46 @@ public abstract class PacketAdapter implements PacketListener {
 	}
 	
 	@Override
-	public ConnectionSide getConnectionSide() {
-		return connectionSide;
+	public ListeningWhitelist getReceivingWhitelist() {
+		return receivingWhitelist;
 	}
 	
 	@Override
-	public Set<Integer> getPacketsID() {
-		return packetsID;
+	public ListeningWhitelist getSendingWhitelist() {
+		return sendingWhitelist;
 	}
 	
 	@Override
-	public String toString() {
+	public Plugin getPlugin() {
+		return plugin;
+	}
+	
+	/**
+	 * Retrieves the name of the plugin that has been associated with the listener.
+	 * @return Name of the associated plugin.
+	 */
+	public static String getPluginName(PacketListener listener) {
+		
+		Plugin plugin = listener.getPlugin();
+		
+		// Try to get the plugin name
+		try {
+			if (plugin == null)
+				return "UNKNOWN";
+			else
+				return plugin.getName();
+			
+		} catch (NoSuchMethodError e) {
+			return plugin.toString();
+		}
+	}
+	
+	@Override
+	public String toString() {		
 		// This is used by the error reporter 
-		return String.format("PacketAdapter[plugin=%s, side=%s, packets=%s]", 
-				plugin.getName(), getConnectionSide().name(), 
-				StringUtils.join(packetsID, ", "));
+		return String.format("PacketAdapter[plugin=%s, sending=%s, receiving=%s]", 
+				getPluginName(this), 
+				sendingWhitelist,
+				receivingWhitelist);
 	}
 }

ProtocolLib/src/com/comphenix/protocol/events/PacketContainer.java

@@ -1,11 +1,42 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.events;
 
-import org.apache.commons.lang.NullArgumentException;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+import org.bukkit.World;
+import org.bukkit.WorldType;
+import org.bukkit.craftbukkit.CraftWorld;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
 import com.comphenix.protocol.injector.StructureCache;
 import com.comphenix.protocol.reflect.EquivalentConverter;
+import com.comphenix.protocol.reflect.FuzzyReflection;
 import com.comphenix.protocol.reflect.StructureModifier;
 
 import net.minecraft.server.Packet;
@@ -15,13 +46,36 @@ import net.minecraft.server.Packet;
  * 
  * @author Kristian
  */
-public class PacketContainer {
+public class PacketContainer implements Serializable {
 
-	protected Packet handle;
-	protected int id;
+	/**
+	 * Generated by Eclipse.
+	 */
+	private static final long serialVersionUID = 2074805748222377230L;
 	
+	protected int id;
+	protected transient Packet handle;
+
 	// Current structure modifier
-	protected StructureModifier<Object> structureModifier;
+	protected transient StructureModifier<Object> structureModifier;
+		
+	// Check whether or not certain classes exists
+	private static boolean hasWorldType = false;
+	
+	// The getEntity method
+	private static Method getEntity;
+	
+	// Support for serialization
+	private static Method writeMethod;
+	private static Method readMethod;
+	
+	static {
+		try {
+			Class.forName("net.minecraft.server.WorldType");
+			hasWorldType = true;
+		} catch (ClassNotFoundException e) {
+		}
+	}
 	
 	/**
 	 * Creates a packet container for a new packet.
@@ -48,7 +102,7 @@ public class PacketContainer {
 	 */
 	public PacketContainer(int id, Packet handle, StructureModifier<Object> structure) {
 		if (handle == null)
-			throw new NullArgumentException("handle");
+			throw new IllegalArgumentException("handle cannot be null.");
 		
 		this.id = id;
 		this.handle = handle;
@@ -71,10 +125,22 @@ public class PacketContainer {
 		return structureModifier;
 	}
 	
-	public <T> StructureModifier<T> getPrimitiveModifier(Class<T> primitiveType) {
+	/**
+	 * Retrieves a read/write structure for every field with the given type.
+	 * @param primitiveType - the type to find.
+	 * @return A modifier for this specific type.
+	 */
+	public <T> StructureModifier<T> getSpecificModifier(Class<T> primitiveType) {
 		return structureModifier.withType(primitiveType);
 	}
 	
+	/**
+	 * Retrieves a read/write structure for ItemStack.
+	 * <p>
+	 * This modifier will automatically marshall between the Bukkit ItemStack and the
+	 * internal Minecraft ItemStack.
+	 * @return A modifier for ItemStack fields.
+	 */
 	public StructureModifier<ItemStack> getItemModifier() {
 		// Convert from and to the Bukkit wrapper
 		return structureModifier.<ItemStack>withType(net.minecraft.server.ItemStack.class, new EquivalentConverter<ItemStack>() {
@@ -86,9 +152,21 @@ public class PacketContainer {
 			public ItemStack getSpecific(Object generic) {
 				return new CraftItemStack((net.minecraft.server.ItemStack) generic);
 			}
+			
+			@Override
+			public Class<ItemStack> getSpecificType() {
+				return ItemStack.class;
+			}
 		});
 	}
 	
+	/**
+	 * Retrieves a read/write structure for arrays of ItemStacks.
+	 * <p>
+	 * This modifier will automatically marshall between the Bukkit ItemStack and the
+	 * internal Minecraft ItemStack.
+	 * @return A modifier for ItemStack array fields.
+	 */
 	public StructureModifier<ItemStack[]> getItemArrayModifier() {
 		// Convert to and from the Bukkit wrapper
 		return structureModifier.<ItemStack[]>withType(net.minecraft.server.ItemStack[].class, new EquivalentConverter<ItemStack[]>() {
@@ -113,6 +191,111 @@ public class PacketContainer {
 				}
 				return result;
 			}
+			
+			@Override
+			public Class<ItemStack[]> getSpecificType() {
+				return ItemStack[].class;
+			}
+		});
+	}
+	
+	/**
+	 * Retrieves a read/write structure for the world type enum.
+	 * <p>
+	 * This modifier will automatically marshall between the Bukkit world type and the
+	 * internal Minecraft world type.
+	 * @return A modifier for world type fields.
+	 */
+	public StructureModifier<WorldType> getWorldTypeModifier() {
+	
+		if (!hasWorldType) {
+			// We couldn't find the Minecraft equivalent
+			return structureModifier.withType(null);
+		}
+		
+		// Convert to and from the Bukkit wrapper
+		return structureModifier.<WorldType>withType(net.minecraft.server.WorldType.class, new EquivalentConverter<WorldType>() {
+			@Override
+			public Object getGeneric(WorldType specific) {
+				return net.minecraft.server.WorldType.getType(specific.getName());
+			}
+			
+			@Override
+			public WorldType getSpecific(Object generic) {
+				net.minecraft.server.WorldType type = (net.minecraft.server.WorldType) generic;
+				return WorldType.getByName(type.name());
+			}
+			
+			@Override
+			public Class<WorldType> getSpecificType() {
+				return WorldType.class;
+			}
+		});
+	}
+	
+	/**
+	 * Retrieves a read/write structure for entity objects.
+	 * <p>
+	 * Note that entities are transmitted by integer ID, and the type may not be enough
+	 * to distinguish between entities and other values. Thus, this structure modifier
+	 * MAY return null or invalid entities for certain fields. Using the correct index 
+	 * is essential.
+	 * 
+	 * @return A modifier entity types.
+	 */
+	public StructureModifier<Entity> getEntityModifier(World world) {
+	
+		final Object worldServer = ((CraftWorld) world).getHandle();
+		final Class<?> nmsEntityClass = net.minecraft.server.Entity.class;
+		final World worldCopy = world;
+		
+		if (getEntity == null)
+			getEntity = FuzzyReflection.fromObject(worldServer).getMethodByParameters(
+					"getEntity", nmsEntityClass, new Class[] { int.class });
+		
+		// Convert to and from the Bukkit wrapper
+		return structureModifier.<Entity>withType(int.class, new EquivalentConverter<Entity>() {
+			@Override
+			public Object getGeneric(Entity specific) {
+				// Simple enough
+				return specific.getEntityId();
+			}
+			
+			@Override
+			public Entity getSpecific(Object generic) {
+				try {
+					net.minecraft.server.Entity nmsEntity = (net.minecraft.server.Entity) 
+							getEntity.invoke(worldServer, generic);
+					Integer id = (Integer) generic;
+					
+					// Attempt to get the Bukkit entity
+					if (nmsEntity != null) {
+						return nmsEntity.getBukkitEntity();
+					} else {
+						// Maybe it's a player that's just logged in? Try a search
+						for (Player player : worldCopy.getPlayers()) {
+							if (player.getEntityId() == id) {
+								return player;
+							}
+						}
+						
+						System.out.println("Entity doesn't exist.");
+						return null;
+					}
+					
+				} catch (IllegalArgumentException e) {
+					throw new RuntimeException("Incorrect arguments detected.", e);
+				} catch (IllegalAccessException e) {
+					throw new RuntimeException("Cannot read field due to a security limitation.", e);
+				} catch (InvocationTargetException e) {
+					throw new RuntimeException("Error occured in Minecraft method.", e.getCause());
+				}
+			}
+			
+			@Override
+			public Class<Entity> getSpecificType() {
+				return Entity.class;
+			}
 		});
 	}
 	
@@ -123,4 +306,60 @@ public class PacketContainer {
 	public int getID() {
 		return id;
 	}
+	
+	private void writeObject(ObjectOutputStream output) throws IOException {
+	    // Default serialization 
+		output.defaultWriteObject();
+
+		// We'll take care of NULL packets as well
+		output.writeBoolean(handle != null);
+		
+		// Retrieve the write method by reflection
+		if (writeMethod == null)
+			writeMethod = FuzzyReflection.fromObject(handle).getMethodByParameters("write", DataOutputStream.class);
+		
+		try {
+			// Call the write-method
+			writeMethod.invoke(handle, new DataOutputStream(output));
+		} catch (IllegalArgumentException e) {
+			throw new IOException("Minecraft packet doesn't support DataOutputStream", e);
+		} catch (IllegalAccessException e) {
+			throw new RuntimeException("Insufficient security privileges.", e);
+		} catch (InvocationTargetException e) {
+			throw new IOException("Could not serialize Minecraft packet.", e);
+		}
+	}
+
+	private void readObject(ObjectInputStream input) throws ClassNotFoundException, IOException {
+	    // Default deserialization
+		input.defaultReadObject();
+		
+		// Get structure modifier
+		structureModifier = StructureCache.getStructure(id);
+
+	    // Don't read NULL packets
+	    if (input.readBoolean()) {
+	    	
+	    	// Create a default instance of the packet
+	    	handle = StructureCache.newPacket(id);
+	    	
+			// Retrieve the read method by reflection
+			if (readMethod == null)
+				readMethod = FuzzyReflection.fromObject(handle).getMethodByParameters("read", DataInputStream.class);
+	    	
+			// Call the read method
+			try {
+				readMethod.invoke(handle, new DataInputStream(input));
+			} catch (IllegalArgumentException e) {
+				throw new IOException("Minecraft packet doesn't support DataInputStream", e);
+			} catch (IllegalAccessException e) {
+				throw new RuntimeException("Insufficient security privileges.", e);
+			} catch (InvocationTargetException e) {
+				throw new IOException("Could not deserialize Minecraft packet.", e);
+			}
+			
+			// And we're done
+			structureModifier = structureModifier.withTarget(handle);
+	    }
+	}
 }

ProtocolLib/src/com/comphenix/protocol/events/PacketEvent.java

@@ -1,20 +1,46 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.events;
 
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.util.EventObject;
 
 import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
 
-public class PacketEvent extends EventObject {
+import com.comphenix.protocol.async.AsyncMarker;
+
+public class PacketEvent extends EventObject implements Cancellable {
 	/**
 	 * Automatically generated by Eclipse.
 	 */
 	private static final long serialVersionUID = -5360289379097430620L;
 
+	private transient Player player;
 	private PacketContainer packet;
-	private Player sender;
-	private Player reciever;
+	private boolean serverPacket;
 	private boolean cancel;
 	
+	private AsyncMarker asyncMarker;
+	private boolean asynchronous;
+	
 	/**
 	 * Use the static constructors to create instances of this event.
 	 * @param source - the event source.
@@ -23,11 +49,21 @@ public class PacketEvent extends EventObject {
 		super(source);
 	}
 
-	private PacketEvent(Object source, PacketContainer packet, Player sender, Player reciever) {
+	private PacketEvent(Object source, PacketContainer packet, Player player, boolean serverPacket) {
 		super(source);
 		this.packet = packet;
-		this.sender = sender;
-		this.reciever = reciever;
+		this.player = player;
+		this.serverPacket = serverPacket;
+	}
+	
+	private PacketEvent(PacketEvent origial, AsyncMarker asyncMarker) {
+		super(origial.source);
+		this.packet = origial.packet;
+		this.player = origial.player;
+		this.cancel = origial.cancel;
+		this.serverPacket = origial.serverPacket;
+		this.asyncMarker = asyncMarker;
+		this.asynchronous = true;
 	}
 
 	/**
@@ -38,7 +74,7 @@ public class PacketEvent extends EventObject {
 	 * @return The event.
 	 */
 	public static PacketEvent fromClient(Object source, PacketContainer packet, Player client) {
-		return new PacketEvent(source, packet, client, null);
+		return new PacketEvent(source, packet, client, false);
 	}
 	
 	/**
@@ -49,7 +85,17 @@ public class PacketEvent extends EventObject {
 	 * @return The event.
 	 */
 	public static PacketEvent fromServer(Object source,  PacketContainer packet, Player recipient) {
-		return new PacketEvent(source, packet, null, recipient);
+		return new PacketEvent(source, packet, recipient, true);
+	}
+	
+	/**
+	 * Create an asynchronous packet event from a synchronous event and a async marker.
+	 * @param event - the original synchronous event.
+	 * @param marker - the asynchronous marker.
+	 * @return The new packet event.
+	 */
+	public static PacketEvent fromSynchronous(PacketEvent event, AsyncMarker marker) {
+		return new PacketEvent(event, marker);
 	}
 	
 	/**
@@ -93,27 +139,76 @@ public class PacketEvent extends EventObject {
 	}
 
 	/**
-	 * Retrieves the player that has sent the packet.
-	 * @return The sender, or NULL if the server is sending the packet.
+	 * Retrieves the player that has sent the packet or is recieving it.
+	 * @return The player associated with this event.
 	 */
-	public Player getSender() {
-		return sender;
+	public Player getPlayer() {
+		return player;
 	}
 	
-	/**
-	 * Retrieves the player that will recieve the packet.
-	 * @return The reciever, or NULL if the server is recieving the packet.
-	 */
-	public Player getReciever() {
-		return reciever;
-	}
-	
-
 	/**
 	 * Whether or not this packet was created by the server.
+	 * <p>
+	 * Most listeners can deduce this by noting which listener method was invoked.
 	 * @return TRUE if the packet was created by the server, FALSE if it was created by a client.
 	 */
 	public boolean isServerPacket() {
-		return getReciever() != null;
+		return serverPacket;
+	}
+	
+	/**
+	 * Retrieve the asynchronous marker.
+	 * <p>
+	 * If the packet is synchronous, this marker will be used to schedule an asynchronous event. In the following
+	 * asynchronous event, the marker is used to correctly pass the packet around to the different threads.
+	 * <p>
+	 * Note that if there are no asynchronous events that can receive this packet, the marker is NULL.
+	 * @return The current asynchronous marker, or NULL.
+	 */
+	public AsyncMarker getAsyncMarker() {
+		return asyncMarker;
+	}
+	/**
+	 * Set the asynchronous marker. 
+	 * <p>
+	 * If the marker is non-null at the end of an synchronous event processing, the packet will be scheduled
+	 * to be processed asynchronously with the given settings.
+	 * <p>
+	 * Note that if there are no asynchronous events that can receive this packet, the marker should be NULL. 
+	 * @param asyncMarker - the new asynchronous marker, or NULL.
+	 * @throws IllegalStateException If the current event is asynchronous.
+	 */
+	public void setAsyncMarker(AsyncMarker asyncMarker) {
+		if (isAsynchronous())
+			throw new IllegalStateException("The marker is immutable for asynchronous events");
+		this.asyncMarker = asyncMarker;
+	}
+
+	/**
+	 * Determine if the packet event has been executed asynchronously or not.
+	 * @return TRUE if this packet event is asynchronous, FALSE otherwise.
+	 */
+	public boolean isAsynchronous() {
+		return asynchronous;
+	}
+	
+	private void writeObject(ObjectOutputStream output) throws IOException {
+	    // Default serialization 
+		output.defaultWriteObject();
+
+		// Write the name of the player (or NULL if it's not set)
+		output.writeObject(player != null ? new SerializedOfflinePlayer(player) : null);
+	}
+
+	private void readObject(ObjectInputStream input) throws ClassNotFoundException, IOException {
+	    // Default deserialization
+		input.defaultReadObject();
+
+		final SerializedOfflinePlayer offlinePlayer = (SerializedOfflinePlayer) input.readObject();
+		
+	    if (offlinePlayer != null) {
+	    	// Better than nothing
+	    	player = offlinePlayer.getPlayer();
+	    }
 	}
 }

ProtocolLib/src/com/comphenix/protocol/events/PacketListener.java

@@ -1,14 +1,38 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.events;
 
-import java.util.Set;
-
+import org.bukkit.plugin.Plugin;
 
+/**
+ * Represents a listener that recieves notifications when packets are sent or recieved.
+ * <p>
+ * Use {@link PacketAdapter} for a simple wrapper around this interface.
+ * @author Kristian
+ */
 public interface PacketListener {
 	
 	/**
 	 * Invoked right before a packet is transmitted from the server to the client.
 	 * <p>
 	 * Note that the packet may be replaced, if needed.
+	 * <p>
+	 * This method is executed on the main thread, and thus the Bukkit API is safe to use.
 	 * 
 	 * @param event - the packet that should be sent.
 	 */
@@ -16,19 +40,30 @@ public interface PacketListener {
 
 	/**
 	 * Invoked right before a recieved packet from a client is being processed.
+	 * <p>
+	 * <b>WARNING</b>: </br> 
+	 * This method will be called <i>asynchronously</i>! You should synchronize with the main 
+	 * thread using {@link org.bukkit.scheduler.BukkitScheduler#scheduleSyncDelayedTask(Plugin, Runnable, long) scheduleSyncDelayedTask} 
+	 * if you need to call the Bukkit API.
 	 * @param event - the packet that has been recieved.
 	 */
 	public void onPacketReceiving(PacketEvent event);
 	
 	/**
-	 * Retrieve whether or not we're listening for client or server packets.
-	 * @return The type of packets we expect.
+	 * Retrieve which packets sent by the server this listener will observe.
+	 * @return List of server packets to observe, along with the priority.
 	 */
-	public ConnectionSide getConnectionSide();
+	public ListeningWhitelist getSendingWhitelist();
 	
 	/**
-	 * Set of packet ids we expect to recieve.
-	 * @return Packets IDs.
+	 * Retrieve which packets sent by the client this listener will observe.
+	 * @return List of server packets to observe, along with the priority.
 	 */
-	public Set<Integer> getPacketsID();
+	public ListeningWhitelist getReceivingWhitelist();
+	
+	/**
+	 * Retrieve the plugin that created list packet listener.
+	 * @return The plugin, or NULL if not available.
+	 */
+	public Plugin getPlugin();
 }

ProtocolLib/src/com/comphenix/protocol/events/SerializedOfflinePlayer.java

@@ -0,0 +1,216 @@
+package com.comphenix.protocol.events;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.Method;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import net.sf.cglib.proxy.Enhancer;
+import net.sf.cglib.proxy.MethodInterceptor;
+import net.sf.cglib.proxy.MethodProxy;
+
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.World;
+import org.bukkit.entity.Player;
+
+/**
+ * Represents a player object that can be serialized by Java.
+ * 
+ * @author Kristian
+ */
+class SerializedOfflinePlayer implements OfflinePlayer, Serializable {
+
+	/**
+	 * Generated by Eclipse.
+	 */
+	private static final long serialVersionUID = -2728976288470282810L;
+
+	private transient Location bedSpawnLocation;
+	
+	// Relevant data about an offline player
+	private String name;
+	private long firstPlayed;
+	private long lastPlayed;
+	private boolean operator;
+	private boolean banned;
+	private boolean playedBefore;
+	private boolean online;
+	private boolean whitelisted;
+	
+	// Proxy helper
+	private static Map<String, Method> lookup = new ConcurrentHashMap<String, Method>();
+
+	/**
+	 * Constructor used by serialization.
+	 */
+	public SerializedOfflinePlayer() {
+		// Do nothing
+	}
+	
+	/**
+	 * Initialize this serializable offline player from another player.
+	 * @param offline - another player.
+	 */
+	public SerializedOfflinePlayer(OfflinePlayer offline) {
+		this.name = offline.getName();
+		this.firstPlayed = offline.getFirstPlayed();
+		this.lastPlayed = offline.getLastPlayed();
+		this.operator = offline.isOp();
+		this.banned = offline.isBanned();
+		this.playedBefore = offline.hasPlayedBefore();
+		this.online = offline.isOnline();
+		this.whitelisted = offline.isWhitelisted();
+	}
+	
+	@Override
+	public boolean isOp() {
+		return operator;
+	}
+
+	@Override
+	public void setOp(boolean operator) {
+		this.operator = operator;
+	}
+
+	@Override
+	public Map<String, Object> serialize() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public Location getBedSpawnLocation() {
+		return bedSpawnLocation;
+	}
+
+	@Override
+	public long getFirstPlayed() {
+		return firstPlayed;
+	}
+
+	@Override
+	public long getLastPlayed() {
+		return lastPlayed;
+	}
+
+	@Override
+	public String getName() {
+		return name;
+	}
+	
+	@Override
+	public boolean hasPlayedBefore() {
+		return playedBefore;
+	}
+
+	@Override
+	public boolean isBanned() {
+		return banned;
+	}
+
+	@Override
+	public void setBanned(boolean banned) {
+		this.banned = banned;
+	}
+	
+	@Override
+	public boolean isOnline() {
+		return online;
+	}
+
+	@Override
+	public boolean isWhitelisted() {
+		return whitelisted;
+	}
+
+	@Override
+	public void setWhitelisted(boolean whitelisted) {
+		this.whitelisted = whitelisted;
+	}
+
+	private void writeObject(ObjectOutputStream output) throws IOException {
+		output.defaultWriteObject();
+		
+		// Serialize the bed spawn location
+		output.writeUTF(bedSpawnLocation.getWorld().getName());
+		output.writeDouble(bedSpawnLocation.getX());
+		output.writeDouble(bedSpawnLocation.getY());
+		output.writeDouble(bedSpawnLocation.getZ());
+	}
+	
+	private void readObject(ObjectInputStream input) throws ClassNotFoundException, IOException {
+		input.defaultReadObject();
+
+		// Well, this is a problem
+		bedSpawnLocation = new Location(
+				getWorld(input.readUTF()),
+				input.readDouble(),
+				input.readDouble(),
+				input.readDouble()
+		);
+	}
+	
+	private World getWorld(String name) {
+		try {
+			// Try to get the world at least
+			return Bukkit.getServer().getWorld(name);
+		} catch (Exception e) {
+			// Screw it
+			return null;
+		}
+	}
+	
+	@Override
+	public Player getPlayer() {
+		try {
+			// Try to get the real player underneath
+			return Bukkit.getServer().getPlayerExact(name);
+		} catch (Exception e) {
+			return getProxyPlayer();
+		}
+	}
+	
+	/**
+	 * Retrieve a player object that implements OfflinePlayer by refering to this object. 
+	 * <p>
+	 * All other methods cause an exception.
+	 * @return Proxy object.
+	 */
+	public Player getProxyPlayer() {
+		
+		// Remember to initialize the method filter
+		if (lookup.size() == 0) {
+			// Add all public methods
+			for (Method method : OfflinePlayer.class.getMethods()) {
+				lookup.put(method.getName(), method);
+			}
+		}
+		
+    	// MORE CGLIB magic!
+    	Enhancer ex = new Enhancer();
+    	ex.setSuperclass(Player.class);
+    	ex.setCallback(new MethodInterceptor() {
+			@Override
+			public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
+				
+				// There's no overloaded methods, so we don't care
+				Method offlineMethod = lookup.get(method.getName());
+				
+				// Ignore all other methods
+				if (offlineMethod == null) {
+					throw new UnsupportedOperationException(
+							"The method " + method.getName() + " is not supported for offline players.");
+				}
+
+				// Invoke our on method
+				return offlineMethod.invoke(SerializedOfflinePlayer.this, args);
+			}
+    	});
+    	
+    	return (Player) ex.create();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/EntityUtilities.java

@@ -0,0 +1,190 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.bukkit.World;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.Player;
+
+import com.comphenix.protocol.injector.PacketConstructor.BukkitUnwrapper;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.FieldUtils;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.google.common.collect.Lists;
+
+/**
+ * Used to perform certain operations on entities.
+ * 
+ * @author Kristian
+ */
+class EntityUtilities {
+
+	private static Field entityTrackerField;
+	private static Field trackedEntitiesField;
+	private static Field trackedPlayersField;
+	
+	private static Method hashGetMethod;
+	private static Method scanPlayersMethod;
+	
+	/*
+	 * While this function may look pretty bad, it's essentially just a reflection-warped 
+	 * version of the following:
+	 * 
+	 *  	@SuppressWarnings("unchecked")
+	 *	 	public static void updateEntity2(Entity entity, List<Player> observers) {
+	 *
+	 *			World world = entity.getWorld();
+	 *			WorldServer worldServer = ((CraftWorld) world).getHandle();
+	 *
+	 *			EntityTracker tracker = worldServer.tracker;
+	 *			EntityTrackerEntry entry = (EntityTrackerEntry) tracker.trackedEntities.get(entity.getEntityId());
+	 *
+	 *			List<EntityPlayer> nmsPlayers = getNmsPlayers(observers);
+	 *
+	 *			entry.trackedPlayers.removeAll(nmsPlayers);
+	 *			entry.scanPlayers(nmsPlayers);
+	 *		}
+	 *
+	 *		private static List<EntityPlayer> getNmsPlayers(List<Player> players) {
+	 *			List<EntityPlayer> nsmPlayers = new ArrayList<EntityPlayer>();
+	 *	
+	 *			for (Player bukkitPlayer : players) {
+	 *				CraftPlayer craftPlayer = (CraftPlayer) bukkitPlayer;
+	 *				nsmPlayers.add(craftPlayer.getHandle());
+	 *			}
+	 *	
+	 *			return nsmPlayers;
+	 *		}
+	 *
+	 */
+	public static void updateEntity(Entity entity, List<Player> observers) throws FieldAccessException {
+		
+		World world = entity.getWorld();
+		Object worldServer = ((CraftWorld) world).getHandle();
+
+		// We have to rely on the class naming here.
+		if (entityTrackerField == null)
+			entityTrackerField = FuzzyReflection.fromObject(worldServer).getFieldByType(".*Tracker");
+		
+		// Get the tracker
+		Object tracker = null;
+		
+		try {
+			tracker = FieldUtils.readField(entityTrackerField, worldServer, false);
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot access 'tracker' field due to security limitations.", e);
+		}
+		
+		if (trackedEntitiesField == null) {
+			@SuppressWarnings("rawtypes")
+			Set<Class> ignoredTypes = new HashSet<Class>();
+			
+			// Well, this is more difficult. But we're looking for a Minecraft object that is not 
+			// created by the constructor(s).
+			for (Constructor<?> constructor : tracker.getClass().getConstructors()) {
+				for (Class<?> type : constructor.getParameterTypes()) {
+					ignoredTypes.add(type);
+				}
+			}
+			
+			// The Minecraft field that's NOT filled in by the constructor
+			trackedEntitiesField = FuzzyReflection.fromObject(tracker, true).
+						getFieldByType(FuzzyReflection.MINECRAFT_OBJECT, ignoredTypes);
+		}
+		
+		// Read the entity hashmap
+		Object trackedEntities = null;
+
+		try {
+			trackedEntities = FieldUtils.readField(trackedEntitiesField, tracker, true);
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot access 'trackedEntities' field due to security limitations.", e);
+		}
+		
+		// Getting the "get" method is pretty hard, but first - try to just get it by name
+		if (hashGetMethod == null) {
+			
+			Class<?> type = trackedEntities.getClass();
+			
+			try {
+				hashGetMethod = type.getMethod("get", int.class);
+			} catch (NoSuchMethodException e) {
+			
+				Class<?>[] params = { int.class };
+				
+				// Then it's probably the lowest named method that takes an int-parameter
+				for (Method method : type.getMethods()) {
+					if (Arrays.equals(params, method.getParameterTypes())) {
+						if (hashGetMethod == null ||
+							method.getName().compareTo(hashGetMethod.getName()) < 0) {
+							hashGetMethod = method;
+						}
+					}
+				}
+			}
+		}
+	
+		try {
+			//EntityTrackerEntry trackEntity = (EntityTrackerEntry) tracker.trackedEntities.get(entity.getEntityId());
+			 Object trackerEntry = hashGetMethod.invoke(trackedEntities, entity.getEntityId());
+
+			if (trackedPlayersField == null) {
+				// This one is fairly easy
+				trackedPlayersField = FuzzyReflection.fromObject(trackerEntry).getFieldByType("java\\.util\\..*");
+			}
+			
+			// Phew, finally there.
+			Collection<?> trackedPlayers = (Collection<?>) FieldUtils.readField(trackedPlayersField, trackerEntry, false);
+			List<Object> nmsPlayers = unwrapBukkit(observers);
+			
+			// trackEntity.trackedPlayers.clear();
+			trackedPlayers.removeAll(nmsPlayers);
+			
+			// We have to rely on a NAME once again. Damn it.
+			if (scanPlayersMethod == null) {
+				scanPlayersMethod = trackerEntry.getClass().getMethod("scanPlayers", List.class);
+			}
+			
+			//trackEntity.scanPlayers(server.players);
+			scanPlayersMethod.invoke(trackerEntry, nmsPlayers);
+			
+		} catch (IllegalArgumentException e) {
+			throw e;
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Security limitation prevents access to 'get' method in IntHashMap", e);
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException("Exception occurred in Minecraft.", e);
+		} catch (SecurityException e) {
+			throw new FieldAccessException("Security limitation prevents access to 'scanPlayers' method in trackerEntry.", e);
+		} catch (NoSuchMethodException e) {
+			throw new FieldAccessException("Canot find 'scanPlayers' method. Is ProtocolLib up to date?", e);
+		}
+	}
+	
+	private static List<Object> unwrapBukkit(List<Player> players) {
+		
+		List<Object> output = Lists.newArrayList();
+		BukkitUnwrapper unwrapper = new BukkitUnwrapper();
+		
+		// Get the NMS equivalent
+		for (Player player : players) {
+			Object result = unwrapper.unwrapItem(player);
+			
+			if (result != null)
+				output.add(result);
+			else
+				throw new IllegalArgumentException("Cannot unwrap item " + player);
+		}
+		
+		return output;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/InjectedArrayList.java

@@ -0,0 +1,115 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Set;
+
+import net.minecraft.server.Packet;
+import net.sf.cglib.proxy.Enhancer;
+import net.sf.cglib.proxy.MethodInterceptor;
+import net.sf.cglib.proxy.MethodProxy;
+
+import com.comphenix.protocol.injector.NetworkFieldInjector.FakePacket;
+
+/**
+ * The array list that notifies when packets are sent by the server.
+ * 
+ * @author Kristian
+ */
+class InjectedArrayList extends ArrayList<Packet> {
+
+	/**
+	 * Silly Eclipse.
+	 */
+	private static final long serialVersionUID = -1173865905404280990L;
+	
+	private PlayerInjector injector;
+	private Set<Packet> ignoredPackets;
+	private ClassLoader classLoader;
+	
+	public InjectedArrayList(ClassLoader classLoader, PlayerInjector injector, Set<Packet> ignoredPackets) {
+		this.classLoader = classLoader;
+		this.injector = injector;
+		this.ignoredPackets = ignoredPackets;
+	}
+
+	@Override
+	public boolean add(Packet packet) {
+
+		Packet result = null;
+		
+		// Check for fake packets and ignored packets
+		if (packet instanceof FakePacket) {
+			return true;
+		} else if (ignoredPackets.contains(packet)) {
+			ignoredPackets.remove(packet);
+		} else {
+			result = injector.handlePacketRecieved(packet);
+		}
+		
+		// A NULL packet indicate cancelling
+		try {
+			if (result != null) {
+				super.add(result);
+			} else {
+				// We'll use the FakePacket marker instead of preventing the filters
+				injector.sendServerPacket(createNegativePacket(packet), true);
+			}
+			
+			// Collection.add contract
+			return true;
+			
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException("Reverting cancelled packet failed.", e.getTargetException());
+		}
+	}
+	
+	/**
+	 * Used by a hack that reverses the effect of a cancelled packet. Returns a packet
+	 * whereby every int method's return value is inverted (a => -a).
+	 * 
+	 * @param source - packet to invert.
+	 * @return The inverted packet.
+	 */
+	Packet createNegativePacket(Packet source) {
+		Enhancer ex = new Enhancer();
+		Class<?> type = source.getClass();
+		
+		// We want to subtract the byte amount that were added to the running
+		// total of outstanding packets. Otherwise, cancelling too many packets
+		// might cause a "disconnect.overflow" error.
+		//
+		// We do that by constructing a special packet of the same type that returns 
+		// a negative integer for all zero-parameter integer methods. This includes the
+		// size() method, which is used by the queue method to count the number of
+		// bytes to add.
+		//
+		// Essentially, we have:
+		//
+		//   public class NegativePacket extends [a packet] {
+		//      @Override
+		//      public int size() {
+		//         return -super.size();
+		//      }
+		//   ect.
+		//   }
+		ex.setInterfaces(new Class[] { FakePacket.class } );
+		ex.setUseCache(true);
+		ex.setClassLoader(classLoader);
+		ex.setSuperclass(type);
+		ex.setCallback(new MethodInterceptor() {
+			@Override
+			public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
+				if (method.getReturnType().equals(int.class) && args.length == 0) {
+					Integer result = (Integer) proxy.invokeSuper(obj, args);
+					return -result;
+				} else {
+					return proxy.invokeSuper(obj, args);
+				}
+			}
+		});
+		
+		return (Packet) ex.create();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/InjectedServerConnection.java

@@ -0,0 +1,189 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.bukkit.Server;
+
+import com.comphenix.protocol.reflect.FieldUtils;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.comphenix.protocol.reflect.VolatileField;
+
+/**
+ * Used to ensure that the 1.3 server is referencing the correct server handler.
+ * 
+ * @author Kristian
+ */
+class InjectedServerConnection {
+	
+	private static Field listenerThreadField;
+	private static Field minecraftServerField;
+	private static Method serverConnectionMethod;
+	private static Field listField;
+	
+	private List<VolatileField> listFields;
+	private List<ReplacedArrayList<Object>> replacedLists;
+	
+	private Server server;
+	private Logger logger;
+	private boolean hasAttempted;
+	private boolean hasSuccess;
+	
+	private Object minecraftServer = null;
+	
+	public InjectedServerConnection(Logger logger, Server server) {
+		this.listFields = new ArrayList<VolatileField>();
+		this.replacedLists = new ArrayList<ReplacedArrayList<Object>>();
+		this.logger = logger;
+		this.server = server;
+	}
+
+	public void injectList() {
+
+		// Only execute this method once
+		if (!hasAttempted)
+			hasAttempted = true;
+		else
+			return;
+		
+		if (minecraftServerField == null)
+			minecraftServerField = FuzzyReflection.fromObject(server, true).getFieldByType(".*MinecraftServer");
+
+		try {
+			minecraftServer = FieldUtils.readField(minecraftServerField, server, true);
+		} catch (IllegalAccessException e1) {
+			logger.log(Level.WARNING, "Cannot extract minecraft server from Bukkit.");
+			return;
+		}
+		
+		try {
+			if (serverConnectionMethod == null)
+				serverConnectionMethod = FuzzyReflection.fromClass(minecraftServerField.getType()).
+											getMethodByParameters("getServerConnection", ".*ServerConnection", new String[] {});
+			// We're using Minecraft 1.3.1
+			injectServerConnection();
+		
+		} catch (RuntimeException e) {
+			
+			// Minecraft 1.2.5 or lower
+			injectListenerThread();
+		}
+	}
+	
+	private void injectListenerThread() {
+	
+		try {
+		
+		if (listenerThreadField == null)
+			listenerThreadField = FuzzyReflection.fromClass(minecraftServerField.getType()).
+				getFieldByType(".*NetworkListenThread");
+		} catch (RuntimeException e) {
+			logger.log(Level.SEVERE, "Cannot find listener thread in MinecraftServer.");
+			return;
+		}
+
+		Object listenerThread = null;
+		
+		// Attempt to get the thread
+		try {
+			listenerThread = listenerThreadField.get(minecraftServer);
+		} catch (Exception e) {
+			logger.log(Level.WARNING, "Unable to read the listener thread.");
+			return;
+		}
+		
+		// Ok, great. Get every list field
+		List<Field> lists = FuzzyReflection.fromClass(listenerThreadField.getType()).getFieldListByType(List.class);
+		
+		for (Field list : lists) {
+			injectIntoList(listenerThread, list);
+		}
+		
+		hasSuccess = true;
+	}
+	
+	private void injectServerConnection() {
+		
+		Object serverConnection = null;
+		
+		// Careful - we might fail
+		try {
+			serverConnection = serverConnectionMethod.invoke(minecraftServer);
+		} catch (Exception ex) {
+			logger.log(Level.WARNING, "Unable to retrieve server connection", ex);
+			return;
+		}
+		
+		if (listField == null)
+			listField = FuzzyReflection.fromClass(serverConnectionMethod.getReturnType(), true).
+							getFieldByType("serverConnection", List.class);
+		injectIntoList(serverConnection, listField);
+		hasSuccess = true;
+	}
+	
+	@SuppressWarnings("unchecked")
+	private void injectIntoList(Object instance, Field field) {
+		VolatileField listFieldRef = new VolatileField(listField, instance, true);
+		List<Object> list = (List<Object>) listFieldRef.getValue();
+
+		// Careful not to inject twice
+		if (list instanceof ReplacedArrayList) {
+			replacedLists.add((ReplacedArrayList<Object>) list);
+		} else {
+			replacedLists.add(new ReplacedArrayList<Object>(list));
+			listFieldRef.setValue(replacedLists.get(0));
+			listFields.add(listFieldRef);
+		}
+	}
+	
+	/**
+	 * Replace the server handler instance kept by the "keep alive" object.
+	 * @param oldHandler - old server handler.
+	 * @param newHandler - new, proxied server handler.
+	 */
+	public void replaceServerHandler(Object oldHandler, Object newHandler) {
+		if (!hasAttempted) {
+			injectList();
+		}
+		
+		if (hasSuccess) {
+			for (ReplacedArrayList<Object> replacedList : replacedLists) {
+				replacedList.addMapping(oldHandler, newHandler);
+			}
+		}
+	}
+	
+	/**
+	 * Revert to the old vanilla server handler, if it has been replaced.
+	 * @param oldHandler - old vanilla server handler.
+	 */
+	public void revertServerHandler(Object oldHandler) {
+		if (hasSuccess) {
+			for (ReplacedArrayList<Object> replacedList : replacedLists) {
+				replacedList.removeMapping(oldHandler);
+			}
+		}
+	}
+	
+	/**
+	 * Undoes everything.
+	 */
+	public void cleanupAll() {
+		if (replacedLists.size() > 0) {
+			// Repair the underlying lists
+			for (ReplacedArrayList<Object> replacedList : replacedLists) {
+				replacedList.revertAll();
+			}
+			for (VolatileField field : listFields) {
+				field.revertValue();
+			}
+			
+			listFields.clear();
+			replacedLists.clear();
+		}
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/MinecraftRegistry.java

@@ -1,15 +1,31 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.injector;
 
 import java.lang.reflect.Field;
 import java.util.HashMap;
 import java.util.Map;
 
-import org.apache.commons.lang.ObjectUtils;
-
 import net.minecraft.server.Packet;
 
 import com.comphenix.protocol.reflect.FieldUtils;
 import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.google.common.base.Objects;
 
 /**
  * Static registries in Minecraft.
@@ -33,7 +49,7 @@ class MinecraftRegistry {
 		// Initialize it, if we haven't already
 		if (packetToID == null) {
 			try {
-				Field packetsField = FuzzyReflection.fromClass(Packet.class, true).getFieldByType("java\\.util\\.Map");
+				Field packetsField = FuzzyReflection.fromClass(Packet.class, true).getFieldByType("packetsField", Map.class);
 				packetToID = (Map<Class, Integer>) FieldUtils.readStaticField(packetsField, true);
 				
 			} catch (IllegalAccessException e) {
@@ -72,13 +88,13 @@ class MinecraftRegistry {
 		Map<Integer, Class> lookup = forceVanilla ? previousValues : overwrittenPackets;
 		
 		// Optimized lookup
-		if (lookup.containsKey(packetToID)) {
-			return lookup.get(packetToID);
+		if (lookup.containsKey(packetID)) {
+			return lookup.get(packetID);
 		}
 
 		// Will most likely not be used
 		for (Map.Entry<Class, Integer> entry : getPacketToID().entrySet()) {
-			if (ObjectUtils.equals(entry.getValue(), packetID)) {
+			if (Objects.equal(entry.getValue(), packetID)) {
 				return entry.getKey();
 			}
 		}

ProtocolLib/src/com/comphenix/protocol/injector/NetworkFieldInjector.java

@@ -0,0 +1,157 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.bukkit.entity.Player;
+
+import com.comphenix.protocol.Packets;
+import com.comphenix.protocol.events.ListeningWhitelist;
+import com.comphenix.protocol.events.PacketListener;
+import com.comphenix.protocol.reflect.FieldUtils;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.comphenix.protocol.reflect.StructureModifier;
+import com.comphenix.protocol.reflect.VolatileField;
+import com.google.common.collect.Sets;
+
+import net.minecraft.server.Packet;
+
+/**
+ * Injection hook that overrides the packet queue lists in NetworkHandler.
+ * 
+ * @author Kristian
+ */
+class NetworkFieldInjector extends PlayerInjector {
+
+	/**
+	 * Marker interface that indicates a packet is fake and should not be processed.
+	 * @author Kristian
+	 */
+	public interface FakePacket {
+		// Nothing
+	}
+	
+	// Packets to ignore
+	private Set<Packet> ignoredPackets = Sets.newSetFromMap(new ConcurrentHashMap<Packet, Boolean>());
+	
+	// Overridden fields
+	private List<VolatileField> overridenLists = new ArrayList<VolatileField>();
+	
+	// Sync field
+	private static Field syncField;
+	private Object syncObject;
+	
+	public NetworkFieldInjector(Player player, PacketFilterManager manager, Set<Integer> sendingFilters) throws IllegalAccessException {
+		super(player, manager, sendingFilters);
+	}
+	
+	@Override
+	protected synchronized void initialize() throws IllegalAccessException {
+		super.initialize();
+	
+		// Get the sync field as well
+		if (hasInitialized) {
+			if (syncField == null)
+				syncField = FuzzyReflection.fromObject(networkManager, true).getFieldByType("java\\.lang\\.Object");
+			syncObject = FieldUtils.readField(syncField, networkManager, true);
+		}
+	}
+
+	@Override
+	public void sendServerPacket(Packet packet, boolean filtered) throws InvocationTargetException {
+		
+		if (networkManager != null) {
+			try {
+				if (!filtered) {
+					ignoredPackets.add(packet);
+				}
+				
+				// Note that invocation target exception is a wrapper for a checked exception
+				queueMethod.invoke(networkManager, packet);
+				
+			} catch (IllegalArgumentException e) {
+				throw e;
+			} catch (InvocationTargetException e) {
+				throw e;
+			} catch (IllegalAccessException e) {
+				throw new IllegalStateException("Unable to access queue method.", e);
+			}
+		} else {
+			throw new IllegalStateException("Unable to load network mananager. Cannot send packet.");
+		}
+	}
+	
+	@Override
+	public void checkListener(PacketListener listener) {
+		// Unfortunately, we don't support chunk packets
+		if (ListeningWhitelist.containsAny(listener.getSendingWhitelist(), 
+				Packets.Server.MAP_CHUNK, Packets.Server.MAP_CHUNK_BULK)) {
+			throw new IllegalStateException("The NETWORK_FIELD_INJECTOR hook doesn't support map chunk listeners.");
+		}
+	}
+	
+	@Override
+	public void injectManager() {
+		
+		if (networkManager != null) {
+
+			@SuppressWarnings("rawtypes")
+			StructureModifier<List> list = networkModifier.withType(List.class);
+
+			// Subclass both send queues
+			for (Field field : list.getFields()) {
+				VolatileField overwriter = new VolatileField(field, networkManager, true);
+				
+				@SuppressWarnings("unchecked")
+				List<Packet> minecraftList = (List<Packet>) overwriter.getOldValue();
+				
+				synchronized(syncObject) {
+					// The list we'll be inserting
+					List<Packet> hackedList = new InjectedArrayList(manager.getClassLoader(), this, ignoredPackets);
+					
+					// Add every previously stored packet
+					for (Packet packet : minecraftList) {
+						hackedList.add(packet);
+					}
+					
+					// Don' keep stale packets around
+					minecraftList.clear();
+					overwriter.setValue(Collections.synchronizedList(hackedList));
+				}
+				
+				overridenLists.add(overwriter);
+			}
+		}
+	}
+	
+	@SuppressWarnings("unchecked")
+	public void cleanupAll() {
+		// Clean up
+		for (VolatileField overriden : overridenLists) {
+			List<Packet> minecraftList = (List<Packet>) overriden.getOldValue();
+			List<Packet> hacketList = (List<Packet>) overriden.getValue();
+			
+			if (minecraftList == hacketList) {
+				return;
+			}
+	
+			// Get a lock before we modify the list
+			synchronized(syncObject) {
+				try {
+					// Copy over current packets
+					for (Packet packet : (List<Packet>) overriden.getValue()) {
+						minecraftList.add(packet);
+					}
+				} finally {
+					overriden.revertValue();
+				}
+			}
+		}
+		overridenLists.clear();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/NetworkObjectInjector.java

@@ -0,0 +1,110 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.InvocationTargetException;
+
+import net.minecraft.server.Packet;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Proxy;
+import java.lang.reflect.Method;
+import java.util.Set;
+
+import org.bukkit.entity.Player;
+
+import com.comphenix.protocol.Packets;
+import com.comphenix.protocol.events.ListeningWhitelist;
+import com.comphenix.protocol.events.PacketListener;
+
+/**
+ * Injection method that overrides the NetworkHandler itself, and it's sendPacket-method.
+ * 
+ * @author Kristian
+ */
+class NetworkObjectInjector extends PlayerInjector {
+	public NetworkObjectInjector(Player player, PacketFilterManager manager, Set<Integer> sendingFilters) throws IllegalAccessException {
+		super(player, manager, sendingFilters);
+	}
+
+	@Override
+	public void sendServerPacket(Packet packet, boolean filtered) throws InvocationTargetException {
+		Object networkDelegate = filtered ? networkManagerRef.getValue() : networkManagerRef.getOldValue();
+		
+		if (networkDelegate != null) {
+			try {
+				// Note that invocation target exception is a wrapper for a checked exception
+				queueMethod.invoke(networkDelegate, packet);
+				
+			} catch (IllegalArgumentException e) {
+				throw e;
+			} catch (InvocationTargetException e) {
+				throw e;
+			} catch (IllegalAccessException e) {
+				throw new IllegalStateException("Unable to access queue method.", e);
+			}
+		} else {
+			throw new IllegalStateException("Unable to load network mananager. Cannot send packet.");
+		}
+	}
+	
+	@Override
+	public void checkListener(PacketListener listener) {
+		// Unfortunately, we don't support chunk packets
+		if (ListeningWhitelist.containsAny(listener.getSendingWhitelist(), 
+				Packets.Server.MAP_CHUNK, Packets.Server.MAP_CHUNK_BULK)) {
+			throw new IllegalStateException("The NETWORK_FIELD_INJECTOR hook doesn't support map chunk listeners.");
+		}
+	}
+	
+	@Override
+	public void injectManager() {
+		
+		if (networkManager != null) {
+			final Class<?> networkInterface = networkManagerField.getType();
+			final Object networkDelegate = networkManagerRef.getOldValue();
+			
+			if (!networkInterface.isInterface()) {
+				throw new UnsupportedOperationException(
+						"Must use CraftBukkit 1.3.0 or later to inject into into NetworkMananger.");
+			}
+			
+			// Create our proxy object
+			Object networkProxy = Proxy.newProxyInstance(networkInterface.getClassLoader(), 
+					new Class<?>[] { networkInterface }, new InvocationHandler() {
+				
+				@Override
+				public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+					// OH OH! The queue method!
+					if (method.equals(queueMethod)) {
+						Packet packet = (Packet) args[0];
+						
+						if (packet != null) {
+							packet = handlePacketRecieved(packet);
+							
+							// A NULL packet indicate cancelling
+							if (packet != null)
+								args[0] = packet;
+							else
+								return null;
+						}
+					}
+					
+					// Delegate to our underlying class
+					try {
+						return method.invoke(networkDelegate, args);
+					} catch (InvocationTargetException e) {
+						throw e.getCause();
+					}
+				}
+			});
+		
+			// Inject it, if we can.
+			networkManagerRef.setValue(networkProxy);
+		}
+	}
+	
+	@Override
+	public void cleanupAll() {
+		// Clean up
+		networkManagerRef.revertValue();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/NetworkServerInjector.java

@@ -0,0 +1,181 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Set;
+
+import net.minecraft.server.Packet;
+import net.sf.cglib.proxy.Enhancer;
+import net.sf.cglib.proxy.Factory;
+import net.sf.cglib.proxy.MethodInterceptor;
+import net.sf.cglib.proxy.MethodProxy;
+
+import org.bukkit.entity.Player;
+
+import com.comphenix.protocol.events.PacketListener;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.FieldUtils;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.comphenix.protocol.reflect.StructureModifier;
+import com.comphenix.protocol.reflect.instances.CollectionGenerator;
+import com.comphenix.protocol.reflect.instances.DefaultInstances;
+import com.comphenix.protocol.reflect.instances.ExistingGenerator;
+import com.comphenix.protocol.reflect.instances.PrimitiveGenerator;
+
+/**
+ * Represents a player hook into the NetServerHandler class. 
+ * 
+ * @author Kristian
+ */
+public class NetworkServerInjector extends PlayerInjector {
+
+	private static Method sendPacketMethod;
+
+	private StructureModifier<Object> serverHandlerModifier;
+	private InjectedServerConnection serverInjection;
+	
+	public NetworkServerInjector(Player player, PacketFilterManager manager, 
+								 Set<Integer> sendingFilters, InjectedServerConnection serverInjection) throws IllegalAccessException {
+		super(player, manager, sendingFilters);
+		this.serverInjection = serverInjection;
+	}
+	
+	@Override
+	protected void initialize() throws IllegalAccessException {
+		super.initialize();
+		
+		// Get the send packet method!
+		if (hasInitialized) {
+			if (sendPacketMethod == null)
+				sendPacketMethod = FuzzyReflection.fromObject(serverHandler).getMethodByName("sendPacket.*");
+			if (serverHandlerModifier == null)
+				serverHandlerModifier = new StructureModifier<Object>(serverHandler.getClass(), null, false);
+		}
+	}
+
+	@Override
+	public void sendServerPacket(Packet packet, boolean filtered) throws InvocationTargetException {
+		Object serverDeleage = filtered ? serverHandlerRef.getValue() : serverHandlerRef.getOldValue();
+		
+		if (serverDeleage != null) {
+			try {
+				// Note that invocation target exception is a wrapper for a checked exception
+				sendPacketMethod.invoke(serverDeleage, packet);
+				
+			} catch (IllegalArgumentException e) {
+				throw e;
+			} catch (InvocationTargetException e) {
+				throw e;
+			} catch (IllegalAccessException e) {
+				throw new IllegalStateException("Unable to access send packet method.", e);
+			}
+		} else {
+			throw new IllegalStateException("Unable to load server handler. Cannot send packet.");
+		}
+	}
+
+	@Override
+	public void injectManager() {
+		
+		if (serverHandlerRef == null)
+			throw new IllegalStateException("Cannot find server handler.");
+		// Don't inject twice
+		if (serverHandlerRef.getValue() instanceof Factory)
+			return;
+		
+		Class<?> serverClass = serverHandler.getClass();
+		
+		Enhancer ex = new Enhancer();
+		ex.setClassLoader(manager.getClassLoader());
+		ex.setSuperclass(serverClass);
+		ex.setCallback(new MethodInterceptor() {
+			@Override
+			public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
+				
+				// The send packet method!
+				if (method.equals(sendPacketMethod)) {
+					Packet packet = (Packet) args[0];
+					
+					if (packet != null) {
+						packet = handlePacketRecieved(packet);
+						
+						// A NULL packet indicate cancelling
+						if (packet != null)
+							args[0] = packet;
+						else
+							return null;
+					}
+				}
+				
+				// Call the method directly
+				return proxy.invokeSuper(obj, args);
+			}
+		});
+		
+		// Use the existing field values when we create our copy
+		DefaultInstances serverInstances = DefaultInstances.fromArray(
+				ExistingGenerator.fromObjectFields(serverHandler),
+				PrimitiveGenerator.INSTANCE, 
+				CollectionGenerator.INSTANCE);
+
+		Object proxyObject = serverInstances.forEnhancer(ex).getDefault(serverClass);
+		serverInjection.replaceServerHandler(serverHandler, proxyObject);
+		
+		// Inject it now
+		if (proxyObject != null) {
+			copyTo(serverHandler, proxyObject);
+			serverHandlerRef.setValue(proxyObject);
+		} else {
+			throw new RuntimeException(
+					"Cannot hook player: Unable to find a valid constructor for the NetServerHandler object.");
+		}
+	}
+	
+	/**
+	 * Copy every field in server handler A to server handler B.
+	 * @param source - fields to copy.
+	 * @param destination - fields to copy to.
+	 */
+	private void copyTo(Object source, Object destination) {
+		StructureModifier<Object> modifierSource = serverHandlerModifier.withTarget(source);
+		StructureModifier<Object> modifierDest = serverHandlerModifier.withTarget(destination);
+		
+		// Copy every field
+		try {
+			for (int i = 0; i < modifierSource.size(); i++) {
+					modifierDest.write(i, modifierSource.read(i));
+			}
+		} catch (FieldAccessException e) {
+			throw new RuntimeException("Unable to copy fields from NetServerHandler.", e);
+		}
+	}
+	
+	@Override
+	public void cleanupAll() {
+		if (serverHandlerRef != null && serverHandlerRef.isCurrentSet()) {
+			copyTo(serverHandlerRef.getValue(), serverHandlerRef.getOldValue());
+			serverHandlerRef.revertValue();
+		}
+		
+		serverInjection.revertServerHandler(serverHandler);
+		
+		try {
+			if (getNetHandler() != null) {
+				// Restore packet listener
+				try {
+					FieldUtils.writeField(netHandlerField, networkManager, serverHandlerRef.getOldValue(), true);
+				} catch (IllegalAccessException e) {
+					// Oh well
+					e.printStackTrace();
+				}
+			}
+		} catch (IllegalAccessException e) {
+			e.printStackTrace();
+		}
+	}
+	
+	@Override
+	public void checkListener(PacketListener listener) {
+		// We support everything
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/PacketConstructor.java

@@ -0,0 +1,231 @@
+package com.comphenix.protocol.injector;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import net.minecraft.server.Packet;
+
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
+
+/**
+ * A packet constructor that uses an internal Minecraft.
+ * @author Kristian
+ *
+ */
+public class PacketConstructor {
+
+	/**
+	 * A packet constructor that automatically converts Bukkit types to their NMS conterpart. 
+	 * <p>
+	 * Remember to call withPacket().
+	 */
+	public static PacketConstructor DEFAULT = new PacketConstructor(null);
+	
+	// The constructor method that's actually responsible for creating the packet
+	private Constructor<?> constructorMethod;
+	
+	// The packet ID
+	private int packetID;
+	
+	// Used to unwrap Bukkit objects
+	private List<Unwrapper> unwrappers;
+	
+	private PacketConstructor(Constructor<?> constructorMethod) {
+		this.constructorMethod = constructorMethod;
+		this.unwrappers = Lists.newArrayList((Unwrapper) new BukkitUnwrapper());
+	}
+	
+	private PacketConstructor(int packetID, Constructor<?> constructorMethod, List<Unwrapper> unwrappers) {
+		this.packetID = packetID;
+		this.constructorMethod = constructorMethod;
+		this.unwrappers = unwrappers;
+	}
+	
+	public ImmutableList<Unwrapper> getUnwrappers() {
+		return ImmutableList.copyOf(unwrappers);
+	}
+	
+	/**
+	 * Retrieve the id of the packets this constructor creates.
+	 * @return The ID of the packets this constructor will create.
+	 */
+	public int getPacketID() {
+		return packetID;
+	}
+	
+	/**
+	 * Return a copy of the current constructor with a different list of unwrappers.
+	 * @param unwrappers - list of unwrappers that convert Bukkit wrappers into the equivalent NMS classes.
+	 * @return A constructor with a different set of unwrappers.
+	 */
+	public PacketConstructor withUnwrappers(List<Unwrapper> unwrappers) {
+		return new PacketConstructor(packetID, constructorMethod, unwrappers);
+	}
+
+	/**
+	 * Create a packet constructor that creates packets using the given types.
+	 * @param id - packet ID.
+	 * @param types - types to create.
+	 * @return A packet constructor with these types.
+	 * @throws IllegalArgumentException If no packet constructor could be created with these types.
+	 */
+	public PacketConstructor withPacket(int id, Object[] values) {
+		
+		Class<?>[] types = new Class<?>[values.length];
+		
+		for (int i = 0; i < types.length; i++) {
+			// Default type
+			if (values[i] != null) {
+				types[i] = values[i].getClass();
+				
+				for (Unwrapper unwrapper : unwrappers) {
+					Object result = unwrapper.unwrapItem(values[i]);
+					
+					// Update type we're searching for
+					if (result != null) {
+						types[i] = result.getClass();
+						break;
+					}
+				}
+			
+			} else {
+				// Try it
+				types[i] = Object.class;
+			}
+		}
+		
+		Class<?> packetType = MinecraftRegistry.getPacketClassFromID(id);
+		
+		if (packetType == null)
+			throw new IllegalArgumentException("Could not find a packet by the id " + id);
+		
+		// Find the correct constructor
+		for (Constructor<?> constructor : packetType.getConstructors()) {
+			Class<?>[] params = constructor.getParameterTypes();
+
+			if (isCompatible(types, params)) {
+				// Right, we've found our type
+				return new PacketConstructor(id, constructor, unwrappers);
+			}
+		}
+		
+		throw new IllegalArgumentException("No suitable constructor could be found.");
+	}
+	
+	/**
+	 * Construct a packet using the special builtin Minecraft constructors.
+	 * @param values - values containing Bukkit wrapped items to pass to Minecraft.
+	 * @return The created packet.
+	 * @throws FieldAccessException Failure due to a security limitation.
+	 * @throws IllegalArgumentException Arguments doesn't match the constructor.
+	 * @throws RuntimeException Minecraft threw an exception.
+	 */
+	public PacketContainer createPacket(Object... values) throws FieldAccessException {
+		
+		try {
+			// Convert types
+			for (int i = 0; i < values.length; i++) {
+				for (Unwrapper unwrapper : unwrappers) {
+					Object converted = unwrapper.unwrapItem(values[i]);
+					
+					if (converted != null) {
+						values[i] = converted;
+						break;
+					}
+				}
+			}
+			
+			Packet nmsPacket = (Packet) constructorMethod.newInstance(values);
+			return new PacketContainer(packetID, nmsPacket);
+			
+		} catch (IllegalArgumentException e) {
+			throw e;
+		} catch (InstantiationException e) {
+			throw new FieldAccessException("Cannot construct an abstract packet.", e);
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot construct packet due to a security limitation.", e);
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException("Minecraft error.", e);
+		}
+	}
+	
+	// Determine if a method with the types 'params' can be called with 'types'
+	private static boolean isCompatible(Class<?>[] types, Class<?>[] params) {
+		
+		// Determine if the types are similar
+		if (params.length == types.length) {
+			for (int i = 0; i < params.length; i++) {
+				if (!params[i].isAssignableFrom(types[i])) {
+					return false;
+				}
+			}
+			
+			return true;
+		}
+		
+		// Parameter count must match
+		return false;
+	}
+
+	public static class BukkitUnwrapper implements Unwrapper {
+	
+		private static Map<Class<?>, Method> cache = new ConcurrentHashMap<Class<?>, Method>();
+	
+		@Override
+		public Object unwrapItem(Object wrappedObject) {
+
+			Class<?> currentClass = wrappedObject.getClass();
+			Method cachedMethod = initializeCache(currentClass);
+			
+			try {
+				// Retrieve the handle
+				if (cachedMethod != null)
+					return cachedMethod.invoke(wrappedObject);
+				else
+					return null;
+				
+			} catch (IllegalArgumentException e) {
+				// Impossible
+				return null;
+			} catch (IllegalAccessException e) {
+				return null;
+			} catch (InvocationTargetException e) {
+				// This is REALLY bad
+				throw new RuntimeException("Minecraft error.", e);
+			}
+		}
+		
+		private Method initializeCache(Class<?> type) {
+			
+			// See if we're already determined this
+			if (cache.containsKey(type)) {
+				// We will never remove from the cache, so this ought to be thread safe
+				return cache.get(type);
+			}
+			
+			try {
+				Method find = type.getMethod("getHandle");
+				
+				// It's thread safe, as getMethod should return the same handle 
+				cache.put(type, find);
+				return find;
+				
+			} catch (SecurityException e) {
+				return null;
+			} catch (NoSuchMethodException e) {
+				return null;
+			}
+		}
+	}
+	
+	public static interface Unwrapper {
+		public Object unwrapItem(Object wrappedObject);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/PacketFilterManager.java

@@ -1,73 +1,176 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.injector;
 
 import java.io.DataInputStream;
 import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import net.minecraft.server.Packet;
+import net.sf.cglib.proxy.Enhancer;
+import net.sf.cglib.proxy.MethodInterceptor;
+import net.sf.cglib.proxy.MethodProxy;
 
-import org.apache.commons.lang.NullArgumentException;
+import org.bukkit.Server;
+import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerJoinEvent;
 import org.bukkit.event.player.PlayerQuitEvent;
+import org.bukkit.event.server.PluginDisableEvent;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.PluginManager;
 
+import com.comphenix.protocol.AsynchronousManager;
 import com.comphenix.protocol.ProtocolManager;
-import com.comphenix.protocol.events.ConnectionSide;
-import com.comphenix.protocol.events.PacketContainer;
-import com.comphenix.protocol.events.PacketEvent;
-import com.comphenix.protocol.events.PacketListener;
+import com.comphenix.protocol.async.AsyncFilterManager;
+import com.comphenix.protocol.async.AsyncMarker;
+import com.comphenix.protocol.events.*;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.google.common.base.Objects;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Sets;
 
 public final class PacketFilterManager implements ProtocolManager {
 
-	private Set<PacketListener> packetListeners = new CopyOnWriteArraySet<PacketListener>();
+	/**
+	 * Sets the inject hook type. Different types allow for maximum compatibility.
+	 * @author Kristian
+	 */
+	public enum PlayerInjectHooks {
+		/**
+		 * Override the packet queue lists in NetworkHandler. 
+		 * <p>
+		 * Cannot intercept MapChunk packets. 
+		 */
+		NETWORK_HANDLER_FIELDS,
+		
+		/**
+		 * Override the network handler object itself. Only works in 1.3.
+		 * <p>
+		 * Cannot intercept MapChunk packets. 
+		 */
+		NETWORK_MANAGER_OBJECT,
+		
+		/**
+		 * Override the server handler object. Versatile, but a tad slower.
+		 */
+		NETWORK_SERVER_OBJECT;
+	}
+	
+	// Create a concurrent set
+	private Set<PacketListener> packetListeners = 
+			Collections.newSetFromMap(new ConcurrentHashMap<PacketListener, Boolean>());
 	
 	// Player injection
-	private Map<DataInputStream, Player> connectionLookup = new HashMap<DataInputStream, Player>();
+	private Map<DataInputStream, Player> connectionLookup = new ConcurrentHashMap<DataInputStream, Player>();
 	private Map<Player, PlayerInjector> playerInjection = new HashMap<Player, PlayerInjector>();
 	
+	// Player injection type
+	private PlayerInjectHooks playerHook = PlayerInjectHooks.NETWORK_HANDLER_FIELDS;
+	
 	// Packet injection
 	private PacketInjector packetInjector;
 	
+	// Server connection injection
+	private InjectedServerConnection serverInjection;
+	
 	// Enabled packet filters
-	private Set<Integer> packetFilters = new HashSet<Integer>();
+	private Set<Integer> sendingFilters = Collections.newSetFromMap(new ConcurrentHashMap<Integer, Boolean>());
+	
+	// The two listener containers
+	private SortedPacketListenerList recievedListeners = new SortedPacketListenerList();
+	private SortedPacketListenerList sendingListeners = new SortedPacketListenerList();
 	
 	// Whether or not this class has been closed
-	private boolean hasClosed;
+	private volatile boolean hasClosed;
+	
+	// The default class loader
+	private ClassLoader classLoader;
+	
+	// The last successful player hook
+	private PlayerInjector lastSuccessfulHook;
 	
 	// Error logger
 	private Logger logger;
 	
+	// The async packet handler
+	private AsyncFilterManager asyncFilterManager;
+	
 	/**
 	 * Only create instances of this class if protocol lib is disabled.
 	 */
-	public PacketFilterManager(ClassLoader classLoader, Logger logger) {
+	public PacketFilterManager(ClassLoader classLoader, Server server, Logger logger) {
 		if (logger == null)
-			throw new NullArgumentException("logger");
+			throw new IllegalArgumentException("logger cannot be NULL.");
 		if (classLoader == null)
-			throw new NullArgumentException("classLoader");
+			throw new IllegalArgumentException("classLoader cannot be NULL.");
 		
 		try {
 			// Initialize values
+			this.classLoader = classLoader;
 			this.logger = logger;
 			this.packetInjector = new PacketInjector(classLoader, this, connectionLookup);
+			this.asyncFilterManager = new AsyncFilterManager(logger, server.getScheduler(), this);
+			this.serverInjection = new InjectedServerConnection(logger, server);
 		} catch (IllegalAccessException e) {
 			logger.log(Level.SEVERE, "Unable to initialize packet injector.", e);
 		}
 	}
 	
+	@Override
+	public AsynchronousManager getAsynchronousManager() {
+		return asyncFilterManager;
+	}
+	
+	/**
+	 * Retrieves how the server packets are read.
+	 * @return Injection method for reading server packets.
+	 */
+	public PlayerInjectHooks getPlayerHook() {
+		return playerHook;
+	}
+
+	/**
+	 * Sets how the server packets are read.
+	 * @param playerHook - the new injection method for reading server packets.
+	 */
+	public void setPlayerHook(PlayerInjectHooks playerHook) {
+		this.playerHook = playerHook;
+		
+		// Make sure the current listeners are compatible
+		if (lastSuccessfulHook != null) {
+			for (PacketListener listener : packetListeners) {
+				checkListener(listener);
+			}
+		}
+	}
+
 	public Logger getLogger() {
 		return logger;
 	}
@@ -80,21 +183,109 @@ public final class PacketFilterManager implements ProtocolManager {
 	@Override
 	public void addPacketListener(PacketListener listener) {
 		if (listener == null)
-			throw new NullArgumentException("listener");
+			throw new IllegalArgumentException("listener cannot be NULL.");
 		
-		packetListeners.add(listener);
-		enablePacketFilters(listener.getConnectionSide(), 
-							listener.getPacketsID());
+		// A listener can only be added once
+		if (packetListeners.contains(listener))
+			return;
+		
+		ListeningWhitelist sending = listener.getSendingWhitelist();
+		ListeningWhitelist receiving = listener.getReceivingWhitelist();
+		boolean hasSending = sending != null && sending.isEnabled();
+		boolean hasReceiving = receiving != null && receiving.isEnabled();
+		
+		if (hasSending || hasReceiving) {
+			// Add listeners and hooks
+			if (hasSending) {
+				verifyWhitelist(listener, sending);
+				sendingListeners.addListener(listener, sending);
+				enablePacketFilters(ConnectionSide.SERVER_SIDE, sending.getWhitelist());
+			}
+			if (hasReceiving) {
+				verifyWhitelist(listener, receiving);
+				recievedListeners.addListener(listener, receiving);
+				enablePacketFilters(ConnectionSide.CLIENT_SIDE, receiving.getWhitelist());
+				
+				// We don't know if we've hooked any players yet
+				checkListener(listener);
+			}
+			
+			// Inform our injected hooks
+			packetListeners.add(listener);
+		}
+	}
+	
+	/**
+	 * Determine if the packet IDs in a whitelist is valid.
+	 * @param listener - the listener that will be mentioned in the error.
+	 * @param whitelist - whitelist of packet IDs.
+	 * @throws IllegalArgumentException If the whitelist is illegal.
+	 */
+	public static void verifyWhitelist(PacketListener listener, ListeningWhitelist whitelist) {
+		for (Integer id : whitelist.getWhitelist()) {
+			if (id >= 256 || id < 0) {
+				throw new IllegalArgumentException(String.format("Invalid packet id %s in listener %s.", 
+							id, PacketAdapter.getPluginName(listener))
+				);
+			}
+		}
+	}
+	
+	/**
+	 * Determine if a listener is valid or not.
+	 * @param listener - listener to check.
+	 * @throws IllegalStateException If the given listener's whitelist cannot be fulfilled.
+	 */
+	public void checkListener(PacketListener listener) {
+		try {
+			if (lastSuccessfulHook != null)
+				lastSuccessfulHook.checkListener(listener);
+		} catch (Exception e) {
+			throw new IllegalStateException("Registering listener " + PacketAdapter.getPluginName(listener) + " failed", e);
+		}
 	}
 	
 	@Override
 	public void removePacketListener(PacketListener listener) {
 		if (listener == null)
-			throw new NullArgumentException("listener");
+			throw new IllegalArgumentException("listener cannot be NULL");
+
+		List<Integer> sendingRemoved = null;
+		List<Integer> receivingRemoved = null;
 		
-		packetListeners.remove(listener);
-		disablePacketFilters(listener.getConnectionSide(),
-						 	 listener.getPacketsID());
+		ListeningWhitelist sending = listener.getSendingWhitelist();
+		ListeningWhitelist receiving = listener.getReceivingWhitelist();
+		
+		// Remove from the overal list of listeners
+		if (!packetListeners.remove(listener))
+			return;
+		
+		// Add listeners
+		if (sending != null && sending.isEnabled())
+			sendingRemoved = sendingListeners.removeListener(listener, sending);
+		if (receiving != null && receiving.isEnabled())
+			receivingRemoved = recievedListeners.removeListener(listener, receiving);
+		
+		// Remove hooks, if needed
+		if (sendingRemoved != null && sendingRemoved.size() > 0)
+			disablePacketFilters(ConnectionSide.SERVER_SIDE, sendingRemoved);
+		if (receivingRemoved != null && receivingRemoved.size() > 0)
+			disablePacketFilters(ConnectionSide.CLIENT_SIDE, receivingRemoved);
+	}
+	
+	@Override
+	public void removePacketListeners(Plugin plugin) {
+		
+		// Iterate through every packet listener
+		for (PacketListener listener : packetListeners) {			
+			// Remove the listener
+			if (Objects.equal(listener.getPlugin(), plugin)) {
+				removePacketListener(listener);
+			}
+		}
+		
+		// Do the same for the asynchronous events
+		asyncFilterManager.unregisterAsyncHandlers(plugin);
 	}
 	
 	/**
@@ -102,15 +293,7 @@ public final class PacketFilterManager implements ProtocolManager {
 	 * @param event - the packet event to invoke.
 	 */
 	public void invokePacketRecieving(PacketEvent event) {
-		for (PacketListener listener : packetListeners) {
-			try {
-				if (canHandlePacket(listener, event))
-					listener.onPacketReceiving(event);
-			} catch (Exception e) {
-				// Minecraft doesn't want your Exception.
-				logger.log(Level.SEVERE, "Exception occured in onPacketReceiving() for " + listener.toString(), e);
-			}
-		}	
+		handlePacket(recievedListeners, event, false);
 	}
 	
 	/**
@@ -118,26 +301,41 @@ public final class PacketFilterManager implements ProtocolManager {
 	 * @param event - the packet event to invoke.
 	 */
 	public void invokePacketSending(PacketEvent event) {
-		for (PacketListener listener : packetListeners) {
-			try {
-				if (canHandlePacket(listener, event))
-					listener.onPacketSending(event);
-			} catch (Exception e) {
-				logger.log(Level.SEVERE, "Exception occured in onPacketReceiving() for " + listener.toString(), e);
-			}
-		}	
+		handlePacket(sendingListeners, event, true);
 	}
 	
-	private boolean canHandlePacket(PacketListener listener, PacketEvent event) {
-		// Make sure the listener is looking for this packet
-		if (!listener.getPacketsID().contains(event.getPacket().getID()))
-			return false;
+	/**
+	 * Handle a packet sending or receiving event.
+	 * <p>
+	 * Note that we also handle asynchronous events.
+	 * @param packetListeners - packet listeners that will receive this event.
+	 * @param event - the evnet to broadcast.
+	 */
+	private void handlePacket(SortedPacketListenerList packetListeners, PacketEvent event, boolean sending) {
 		
-		// And this type of packet
-		if (event.isServerPacket())
-			return listener.getConnectionSide().isForServer();
+		// By default, asynchronous packets are queued for processing
+		if (asyncFilterManager.hasAsynchronousListeners(event)) {
+			event.setAsyncMarker(asyncFilterManager.createAsyncMarker());
+		}
+		
+		// Process synchronous events
+		if (sending)
+			packetListeners.invokePacketSending(logger, event);
 		else
-			return listener.getConnectionSide().isForClient();
+			packetListeners.invokePacketRecieving(logger, event);
+		
+		// To cancel asynchronous processing, use the async marker
+		if (!event.isCancelled() && !hasAsyncCancelled(event.getAsyncMarker())) {
+			asyncFilterManager.enqueueSyncPacket(event, event.getAsyncMarker());
+
+			// The above makes a copy of the event, so it's safe to cancel it
+			event.setCancelled(true);
+		}
+	}
+	
+	// NULL marker mean we're dealing with no asynchronous listeners 
+	private boolean hasAsyncCancelled(AsyncMarker marker) {
+		return marker == null || marker.isAsyncCancelled();
 	}
 	
 	/**
@@ -148,13 +346,13 @@ public final class PacketFilterManager implements ProtocolManager {
 	 * @param side - which side the event will arrive from.
 	 * @param packets - the packet id(s).
 	 */
-	private void enablePacketFilters(ConnectionSide side, Set<Integer> packets) {
+	private void enablePacketFilters(ConnectionSide side, Iterable<Integer> packets) {
 		if (side == null)
-			throw new NullArgumentException("side");
+			throw new IllegalArgumentException("side cannot be NULL.");
 		
 		for (int packetID : packets) {
-			if (side.isForServer())
-				packetFilters.add(packetID);
+			if (side.isForServer()) 
+				sendingFilters.add(packetID);
 			if (side.isForClient() && packetInjector != null)
 				packetInjector.addPacketHandler(packetID);
 		}
@@ -165,13 +363,13 @@ public final class PacketFilterManager implements ProtocolManager {
 	 * @param packets - the packet id(s).
 	 * @param side - which side the event no longer should arrive from.
 	 */
-	private void disablePacketFilters(ConnectionSide side, Set<Integer> packets) {
+	private void disablePacketFilters(ConnectionSide side, Iterable<Integer> packets) {
 		if (side == null)
-			throw new NullArgumentException("side");
+			throw new IllegalArgumentException("side cannot be NULL.");
 		
 		for (int packetID : packets) {
 			if (side.isForServer())
-				packetFilters.remove(packetID);
+				sendingFilters.remove(packetID);
 			if (side.isForClient() && packetInjector != null) 
 				packetInjector.removePacketHandler(packetID);
 		}
@@ -185,9 +383,9 @@ public final class PacketFilterManager implements ProtocolManager {
 	@Override
 	public void sendServerPacket(Player reciever, PacketContainer packet, boolean filters) throws InvocationTargetException {
 		if (reciever == null)
-			throw new NullArgumentException("reciever");
+			throw new IllegalArgumentException("reciever cannot be NULL.");
 		if (packet == null)
-			throw new NullArgumentException("packet");
+			throw new IllegalArgumentException("packet cannot be NULL.");
 		
 		getInjector(reciever).sendServerPacket(packet.getHandle(), filters);
 	}
@@ -201,13 +399,16 @@ public final class PacketFilterManager implements ProtocolManager {
 	public void recieveClientPacket(Player sender, PacketContainer packet, boolean filters) throws IllegalAccessException, InvocationTargetException {
 		
 		if (sender == null)
-			throw new NullArgumentException("sender");
+			throw new IllegalArgumentException("sender cannot be NULL.");
 		if (packet == null)
-			throw new NullArgumentException("packet");
+			throw new IllegalArgumentException("packet cannot be NULL.");
 		
 		PlayerInjector injector = getInjector(sender);
 		Packet mcPacket = packet.getHandle();
 		
+		// Make sure the packet isn't cancelled
+		packetInjector.undoCancel(packet.getID(), mcPacket);
+		
 		if (filters) {
 			mcPacket = injector.handlePacketRecieved(mcPacket);
 		}
@@ -217,15 +418,43 @@ public final class PacketFilterManager implements ProtocolManager {
 	
 	@Override
 	public PacketContainer createPacket(int id) {
-		return new PacketContainer(id);
+		return createPacket(id, true);
 	}
 	
 	@Override
-	public Set<Integer> getPacketFilters() {
-		if (packetInjector != null)
-			return Sets.union(packetFilters, packetInjector.getPacketHandlers());
-		else
-			return packetFilters;
+	public PacketContainer createPacket(int id, boolean forceDefaults) {
+		PacketContainer packet = new PacketContainer(id);
+		
+		// Use any default values if possible
+		if (forceDefaults) {
+			try {
+				packet.getModifier().writeDefaults();
+			} catch (FieldAccessException e) {
+				throw new RuntimeException("Security exception.", e);
+			}
+		}
+		
+		return packet;
+	}
+	
+	@Override
+	public PacketConstructor createPacketConstructor(int id, Object... arguments) {
+		return PacketConstructor.DEFAULT.withPacket(id, arguments);
+	}
+
+	@Override
+	public Set<Integer> getSendingFilters() {
+		return ImmutableSet.copyOf(sendingFilters);
+	}
+	
+	@Override
+	public Set<Integer> getReceivingFilters() {
+		return ImmutableSet.copyOf(packetInjector.getPacketHandlers());
+	}
+	
+	@Override
+	public void updateEntity(Entity entity, List<Player> observers) throws FieldAccessException {
+		EntityUtilities.updateEntity(entity, observers);
 	}
 	
 	/**
@@ -237,21 +466,77 @@ public final class PacketFilterManager implements ProtocolManager {
 			injectPlayer(player);
 	}
 	
-	private void injectPlayer(Player player) {
+	/**
+	 * Used to construct a player hook.
+	 * @param player - the player to hook.
+	 * @param hook - the hook type.
+	 * @return A new player hoook
+	 * @throws IllegalAccessException Unable to do our reflection magic.
+	 */
+	protected PlayerInjector getHookInstance(Player player, PlayerInjectHooks hook) throws IllegalAccessException {
+		// Construct the correct player hook
+		switch (hook) {
+		case NETWORK_HANDLER_FIELDS: 
+			return new NetworkFieldInjector(player, this, sendingFilters);
+		case NETWORK_MANAGER_OBJECT: 
+			return new NetworkObjectInjector(player, this, sendingFilters);
+		case NETWORK_SERVER_OBJECT:
+			return new NetworkServerInjector(player, this, sendingFilters, serverInjection);
+		default:
+			throw new IllegalArgumentException("Cannot construct a player injector.");
+		}
+	}
+	
+	/**
+	 * Initialize a player hook, allowing us to read server packets.
+	 * @param player - player to hook.
+	 */
+	protected void injectPlayer(Player player) {
+		
+		PlayerInjector injector = null;
+		PlayerInjectHooks currentHook = playerHook;
+		boolean firstPlayer = lastSuccessfulHook == null;
+		
 		// Don't inject if the class has closed
 		if (!hasClosed && player != null && !playerInjection.containsKey(player)) {
-			try {
-				PlayerInjector injector = new PlayerInjector(player, this, packetFilters);
-				
-				injector.injectManager();
-				playerInjection.put(player, injector);
-				connectionLookup.put(injector.getInputStream(false), player);
-				
-			} catch (IllegalAccessException e) {
-				// Mark this injection attempt as a failure
-				playerInjection.put(player, null);
-				logger.log(Level.SEVERE, "Unable to access fields.", e);
+			while (true) {
+				try {
+					injector = getHookInstance(player, currentHook);
+					injector.injectManager();
+					playerInjection.put(player, injector);
+					connectionLookup.put(injector.getInputStream(false), player);
+					break;
+					
+				} catch (Exception e) {
+
+					// Mark this injection attempt as a failure
+					logger.log(Level.SEVERE, "Player hook " + currentHook.toString() + " failed.", e);
+					
+					// Clean up as much as possible
+					try {
+						if (injector != null)
+							injector.cleanupAll();
+					} catch (Exception e2) {
+						logger.log(Level.WARNING, "Cleaing up after player hook failed.", e);
+					}
+					
+					if (currentHook.ordinal() > 0) {
+						// Choose the previous player hook type
+						currentHook = PlayerInjectHooks.values()[currentHook.ordinal() - 1];
+						logger.log(Level.INFO, "Switching to " + currentHook.toString() + " instead.");
+					} else {
+						// UTTER FAILURE
+						playerInjection.put(player, null);
+						return;
+					}
+				}
 			}
+			
+			// Update values
+			if (injector != null)
+				lastSuccessfulHook = injector;
+			if (currentHook != playerHook || firstPlayer) 
+				setPlayerHook(currentHook);
 		}
 	}
 	
@@ -260,31 +545,133 @@ public final class PacketFilterManager implements ProtocolManager {
 	 * @param manager - Bukkit plugin manager that provides player join/leave events.
 	 * @param plugin - the parent plugin.
 	 */
-	public void registerEvents(PluginManager manager, Plugin plugin) {
-		manager.registerEvents(new Listener() {
+	public void registerEvents(PluginManager manager, final Plugin plugin) {
+		
+		try {
+			manager.registerEvents(new Listener() {
+				
+				@EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
+			    public void onPlayerJoin(PlayerJoinEvent event) {
+					injectPlayer(event.getPlayer());
+			    }
+				
+				@EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
+			    public void onPlayerQuit(PlayerQuitEvent event) {
+					uninjectPlayer(event.getPlayer());
+			    }
+				
+				@EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
+			    public void onPluginDisabled(PluginDisableEvent event) {
+					// Clean up in case the plugin forgets
+					if (event.getPlugin() != plugin) {
+						removePacketListeners(event.getPlugin());
+					}
+			    }
+				
+			}, plugin);
+		
+		} catch (NoSuchMethodError e) {
+			// Oh wow! We're running on 1.0.0 or older.
+			registerOld(manager, plugin);
+		}
+	}
+	
+	// Yes, this is crazy.
+	@SuppressWarnings({ "unchecked", "rawtypes" })
+	private void registerOld(PluginManager manager, Plugin plugin) {
+		
+		try {
+			ClassLoader loader = manager.getClass().getClassLoader();
 			
-			@EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
-		    public void onPlayerJoin(PlayerJoinEvent event) {
-				injectPlayer(event.getPlayer());
-		    }
+			// The different enums we are going to need
+			Class eventTypes = loader.loadClass("org.bukkit.event.Event$Type");
+			Class eventPriority = loader.loadClass("org.bukkit.event.Event$Priority");
 			
-			@EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
-		    public void onPlayerQuit(PlayerQuitEvent event) {
-				uninjectPlayer(event.getPlayer());
-		    }
-		}, plugin);
+			// Get the priority
+			Object priorityNormal = Enum.valueOf(eventPriority, "Normal");
+			
+			// Get event types
+			Object playerJoinType = Enum.valueOf(eventTypes, "PLAYER_JOIN");
+			Object playerQuitType = Enum.valueOf(eventTypes, "PLAYER_QUIT");
+			Object pluginDisabledType = Enum.valueOf(eventTypes, "PLUGIN_DISABLE");
+			
+			// The player listener! Good times.
+			Class<?> playerListener = loader.loadClass("org.bukkit.event.player.PlayerListener");
+			Class<?> serverListener = loader.loadClass("org.bukkit.event.server.ServerListener");
+			
+			// Find the register event method
+			Method registerEvent = FuzzyReflection.fromObject(manager).getMethodByParameters("registerEvent", 
+					eventTypes, Listener.class, eventPriority, Plugin.class);
+
+			Enhancer playerEx = new Enhancer();
+			Enhancer serverEx = new Enhancer();
+			
+			playerEx.setSuperclass(playerListener);
+			playerEx.setClassLoader(classLoader);
+			playerEx.setCallback(new MethodInterceptor() {
+				@Override
+				public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
+					// Must have a parameter
+					if (args.length == 1) {
+						Object event = args[0];
+						
+						// Check for the correct event
+						if (event instanceof PlayerJoinEvent)
+							injectPlayer(((PlayerJoinEvent) event).getPlayer());
+						else if (event instanceof PlayerQuitEvent)
+							uninjectPlayer(((PlayerQuitEvent) event).getPlayer());
+					}
+					return null;
+				}
+			});
+			
+			serverEx.setSuperclass(serverListener);
+			serverEx.setClassLoader(classLoader);
+			serverEx.setCallback(new MethodInterceptor() {
+				@Override
+				public Object intercept(Object obj, Method method, Object[] args,
+						MethodProxy proxy) throws Throwable {
+					// Must have a parameter
+					if (args.length == 1) {
+						Object event = args[0];
+						
+						if (event instanceof PluginDisableEvent)
+							removePacketListeners(((PluginDisableEvent) event).getPlugin());
+					}
+					return null;
+				}
+			});
+			
+			// Create our listener
+			Object playerProxy = playerEx.create();
+			Object serverProxy = serverEx.create();
+			
+			registerEvent.invoke(manager, playerJoinType, playerProxy, priorityNormal, plugin);
+			registerEvent.invoke(manager, playerQuitType, playerProxy, priorityNormal, plugin);
+			registerEvent.invoke(manager, pluginDisabledType, serverProxy, priorityNormal, plugin);
+			
+			// A lot can go wrong
+		} catch (ClassNotFoundException e1) {
+			e1.printStackTrace();
+		} catch (IllegalArgumentException e) {
+			e.printStackTrace();
+		} catch (IllegalAccessException e) {
+			e.printStackTrace();
+		} catch (InvocationTargetException e) {
+			e.printStackTrace();
+		}
 	}
 	
 	private void uninjectPlayer(Player player) {
 		if (!hasClosed && player != null) {
 			
 			PlayerInjector injector = playerInjection.get(player);
-			DataInputStream input = injector.getInputStream(true);
 			
 			if (injector != null) {
+				DataInputStream input = injector.getInputStream(true);
 				injector.cleanupAll();
 				
-				playerInjection.remove(injector);
+				playerInjection.remove(player);
 				connectionLookup.remove(input);
 			}
 		}	
@@ -305,6 +692,14 @@ public final class PacketFilterManager implements ProtocolManager {
 			throw new IllegalArgumentException("Player has no injected handler.");
 	}
 	
+	/**
+	 * Retrieves the current plugin class loader.
+	 * @return Class loader.
+	 */
+	public ClassLoader getClassLoader() {
+		return classLoader;
+	}
+	
 	@Override
 	public boolean isClosed() {
 		return hasClosed;
@@ -312,21 +707,31 @@ public final class PacketFilterManager implements ProtocolManager {
 	
 	public void close() {
 		// Guard
-		if (hasClosed)
+		if (hasClosed || playerInjection == null)
 			return;
-		
+
 		// Remove everything
 		for (PlayerInjector injection : playerInjection.values()) {
-			injection.cleanupAll();
+			if (injection != null) {
+				injection.cleanupAll();
+			}
 		}
-		
+
 		// Remove packet handlers
 		if (packetInjector != null)
 			packetInjector.cleanupAll();
 		
+		// Remove server handler
+		serverInjection.cleanupAll();
+		hasClosed = true;
+		
+		// Remove listeners
+		packetListeners.clear();
 		playerInjection.clear();
 		connectionLookup.clear();
-		hasClosed = true;
+		
+		// Clean up async handlers. We have to do this last.
+		asyncFilterManager.cleanupAll();
 	}
 	
 	@Override

ProtocolLib/src/com/comphenix/protocol/injector/PacketInjector.java

@@ -1,3 +1,20 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.injector;
 
 import java.io.DataInputStream;
@@ -6,6 +23,7 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.bukkit.entity.Player;
 
@@ -15,6 +33,7 @@ import net.sf.cglib.proxy.Enhancer;
 
 import com.comphenix.protocol.events.PacketContainer;
 import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.reflect.FieldUtils;
 import com.comphenix.protocol.reflect.FuzzyReflection;
 
 /**
@@ -34,6 +53,9 @@ class PacketInjector {
 	// Allows us to determine the sender
 	private Map<DataInputStream, Player> playerLookup;
 	
+	// Allows us to look up read packet injectors
+	private Map<Integer, ReadPacketModifier> readModifier;
+	
 	// Class loader
 	private ClassLoader classLoader;
 			
@@ -43,16 +65,31 @@ class PacketInjector {
 		this.classLoader = classLoader;
 		this.manager = manager;
 		this.playerLookup = playerLookup;
+		this.readModifier = new ConcurrentHashMap<Integer, ReadPacketModifier>();
 		initialize();
 	}
 	
+	/**
+	 * Undo a packet cancel.
+	 * @param id - the id of the packet.
+	 * @param packet - packet to uncancel.
+	 */
+	public void undoCancel(Integer id, Packet packet) {
+		ReadPacketModifier modifier = readModifier.get(id);
+		
+		// Cancelled packets are represented with NULL
+		if (modifier != null && modifier.getOverride(packet) == null) {
+			modifier.removeOverride(packet);
+		}
+	}
+	
 	private void initialize() throws IllegalAccessException {
 		if (intHashMap == null) {
 			// We're looking for the first static field with a Minecraft-object. This should be a IntHashMap.
-			Field intHashMapField = FuzzyReflection.fromClass(Packet.class).getFieldByType(FuzzyReflection.MINECRAFT_OBJECT);
+			Field intHashMapField = FuzzyReflection.fromClass(Packet.class, true).getFieldByType(FuzzyReflection.MINECRAFT_OBJECT);
 			
 			try {
-				intHashMap = intHashMapField.get(null);
+				intHashMap = FieldUtils.readField(intHashMapField, (Object) null, true);
 			} catch (IllegalArgumentException e) {
 				throw new RuntimeException("Minecraft is incompatible.", e);
 			}
@@ -91,10 +128,12 @@ class PacketInjector {
 		ex.setClassLoader(classLoader);
 		Class proxy = ex.createClass();
 		
+		// Create the proxy handler
+		ReadPacketModifier modifier = new ReadPacketModifier(packetID, this);
+		readModifier.put(packetID, modifier);
+		
 		// Add a static reference
-		Enhancer.registerStaticCallbacks(proxy, new Callback[] { 
-				new ReadPacketModifier(packetID, this) 
-		});
+		Enhancer.registerStaticCallbacks(proxy, new Callback[] { modifier });
 		
 		try {
 			// Override values
@@ -129,6 +168,7 @@ class PacketInjector {
 			
 			putMethod.invoke(intHashMap, packetID, old);
 			previous.remove(packetID);
+			readModifier.remove(packetID);
 			registry.remove(proxy);
 			overwritten.remove(packetID);
 			return true;

ProtocolLib/src/com/comphenix/protocol/injector/PlayerInjector.java

@@ -1,11 +1,26 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.injector;
 
 import java.io.DataInputStream;
 import java.lang.reflect.Field;
-import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.lang.reflect.Proxy;
 import java.util.Set;
 
 import net.minecraft.server.EntityPlayer;
@@ -16,49 +31,65 @@ import org.bukkit.entity.Player;
 
 import com.comphenix.protocol.events.PacketContainer;
 import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.events.PacketListener;
 import com.comphenix.protocol.reflect.FieldUtils;
 import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.comphenix.protocol.reflect.StructureModifier;
 import com.comphenix.protocol.reflect.VolatileField;
 
-class PlayerInjector {
-
+abstract class PlayerInjector {
+	
 	// Cache previously retrieved fields
-	private static Field serverHandlerField;
-	private static Field networkManagerField;
-	private static Field inputField;
-	private static Field netHandlerField;
+	protected static Field serverHandlerField;
+	protected static Field networkManagerField;
+	protected static Field inputField;
+	protected static Field netHandlerField;
+	
+	// To add our injected array lists
+	protected static StructureModifier<Object> networkModifier;
 	
 	// And methods
-	private static Method queueMethod;
-	private static Method processMethod;
+	protected static Method queueMethod;
+	protected static Method processMethod;
 		
-	private Player player;
-	private boolean hasInitialized;
-
+	protected Player player;
+	protected boolean hasInitialized;
+	
 	// Reference to the player's network manager
-	private VolatileField networkManager;
-	
-	// The packet manager and filters
-	private PacketFilterManager manager;
-	private Set<Integer> packetFilters;
-	
-	// Previous data input
-	private DataInputStream cachedInput;
+	protected VolatileField networkManagerRef;
+	protected VolatileField serverHandlerRef;
+	protected Object networkManager;
 	
 	// Current net handler
-	private Object netHandler;
+	protected Object serverHandler;
+	protected Object netHandler;
+	
+	// The packet manager and filters
+	protected PacketFilterManager manager;
+	protected Set<Integer> sendingFilters;
+	
+	// Previous data input
+	protected DataInputStream cachedInput;
 
-	public PlayerInjector(Player player, PacketFilterManager manager, Set<Integer> packetFilters) throws IllegalAccessException {
+	public PlayerInjector(Player player, PacketFilterManager manager, Set<Integer> sendingFilters) throws IllegalAccessException {
 		this.player = player;
 		this.manager = manager;
-		this.packetFilters = packetFilters;
+		this.sendingFilters = sendingFilters;
 		initialize();
 	}
 
-	private void initialize() throws IllegalAccessException {
-	
+	/**
+	 * Retrieve the notch (NMS) entity player object.
+	 * @return Notch player object.
+	 */
+	protected EntityPlayer getEntityPlayer() {
 		CraftPlayer craft = (CraftPlayer) player;
-		EntityPlayer notchEntity = craft.getHandle();
+		return craft.getHandle();
+	}
+	
+	protected void initialize() throws IllegalAccessException {
+	
+		EntityPlayer notchEntity = getEntityPlayer();
 		
 		if (!hasInitialized) {
 			// Do this first, in case we encounter an exception
@@ -67,12 +98,18 @@ class PlayerInjector {
 			// Retrieve the server handler
 			if (serverHandlerField == null)
 				serverHandlerField = FuzzyReflection.fromObject(notchEntity).getFieldByType(".*NetServerHandler");
-			Object serverHandler = FieldUtils.readField(serverHandlerField, notchEntity);
+			serverHandlerRef = new VolatileField(serverHandlerField, notchEntity);
+			serverHandler = serverHandlerRef.getValue();
 			
 			// Next, get the network manager 
-			if (networkManagerField == null)
+			if (networkManagerField == null) 
 				networkManagerField = FuzzyReflection.fromObject(serverHandler).getFieldByType(".*NetworkManager");
-			networkManager = new VolatileField(networkManagerField, serverHandler);
+			networkManagerRef = new VolatileField(networkManagerField, serverHandler);
+			networkManager = networkManagerRef.getValue();
+			
+			// Create the network manager modifier from the actual object type
+			if (networkManager != null && networkModifier == null)
+				networkModifier = new StructureModifier<Object>(networkManager.getClass(), null, false);
 			
 			// And the queue method
 			if (queueMethod == null)
@@ -81,7 +118,7 @@ class PlayerInjector {
 			
 			// And the data input stream that we'll use to identify a player
 			if (inputField == null)
-				inputField = FuzzyReflection.fromObject(networkManager.getOldValue(), true).
+				inputField = FuzzyReflection.fromObject(networkManager, true).
 								getFieldByType("java\\.io\\.DataInputStream");
 		}
 	}
@@ -91,27 +128,32 @@ class PlayerInjector {
 	 * @return Current net handler.
 	 * @throws IllegalAccessException Unable to find or retrieve net handler.
 	 */
-	private Object getNetHandler() throws IllegalAccessException {
+	protected Object getNetHandler() throws IllegalAccessException {
 		
 		// What a mess
 		try {
 			if (netHandlerField == null)
-				netHandlerField = FuzzyReflection.fromClass(networkManagerField.getType(), true).
+				netHandlerField = FuzzyReflection.fromClass(networkManager.getClass(), true).
 									getFieldByType("net\\.minecraft\\.NetHandler");
 		} catch (RuntimeException e1) {
+			// Swallow it
+		}
+		
+		// Second attempt
+		if (netHandlerField == null) {
 			try {
 				// Well, that sucks. Try just Minecraft objects then.
-				netHandlerField = FuzzyReflection.fromClass(networkManagerField.getType(), true).
+				netHandlerField = FuzzyReflection.fromClass(networkManager.getClass(), true).
 									 getFieldByType(FuzzyReflection.MINECRAFT_OBJECT);
 				
 			} catch (RuntimeException e2) {
-				return new IllegalAccessException("Cannot locate net handler. " + e2.getMessage());
+				throw new IllegalAccessException("Cannot locate net handler. " + e2.getMessage());
 			}
 		}
 		
 		// Get the handler
-		if (netHandler != null)
-			netHandler = FieldUtils.readField(netHandlerField, networkManager.getOldValue(), true);
+		if (netHandler == null)
+			netHandler = FieldUtils.readField(netHandlerField, networkManager, true);
 		return netHandler;
 	}
 	
@@ -151,66 +193,25 @@ class PlayerInjector {
 	 * @param filtered - whether or not the packet will be filtered by our listeners.
 	 * @param InvocationTargetException If an error occured when sending the packet.
 	 */
-	public void sendServerPacket(Packet packet, boolean filtered) throws InvocationTargetException {
-		Object networkDelegate = filtered ? networkManager.getValue() : networkManager.getOldValue();
-		
-		if (networkDelegate != null) {
-			try {
-				// Note that invocation target exception is a wrapper for a checked exception
-				queueMethod.invoke(networkDelegate, packet);
-				
-			} catch (IllegalArgumentException e) {
-				throw e;
-			} catch (InvocationTargetException e) {
-				throw e;
-			} catch (IllegalAccessException e) {
-				throw new IllegalStateException("Unable to access queue method.", e);
-			}
-		} else {
-			throw new IllegalStateException("Unable to load network mananager. Cannot send packet.");
-		}
-	}
+	public abstract void sendServerPacket(Packet packet, boolean filtered) throws InvocationTargetException;
 	
-	public void injectManager() {
-		
-		if (networkManager != null) {
-			final Class<?> networkInterface = networkManagerField.getType();
-			final Object networkDelegate = networkManager.getOldValue();
-			
-			// Create our proxy object
-			Object networkProxy = Proxy.newProxyInstance(networkInterface.getClassLoader(), 
-					new Class<?>[] { networkInterface }, new InvocationHandler() {
-				
-				@Override
-				public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
-					// OH OH! The queue method!
-					if (method.equals(queueMethod)) {
-						Packet packet = (Packet) args[0];
-						
-						if (packet != null) {
-							packet = handlePacketRecieved(packet);
-							
-							// A NULL packet indicate cancelling
-							if (packet != null)
-								args[0] = packet;
-							else
-								return null;
-						}
-					}
-					
-					// Delegate to our underlying class
-					try {
-						return method.invoke(networkDelegate, args);
-					} catch (InvocationTargetException e) {
-						throw e.getCause();
-					}
-				}
-			});
-		
-			// Inject it, if we can.
-			networkManager.setValue(networkProxy);
-		}
-	}
+	/**
+	 * Inject a hook to catch packets sent to the current player.
+	 */
+	public abstract void injectManager();
+	
+	/**
+	 * Remove all hooks and modifications.
+	 */
+	public abstract void cleanupAll();
+	
+	/**
+	 * Invoked before a new listener is registered.
+	 * <p>
+	 * The player injector should throw an exception if this listener cannot be properly supplied with packet events. 
+	 * @param listener - the listener that is about to be registered.
+	 */
+	public abstract void checkListener(PacketListener listener);
 	
 	/**
 	 * Allows a packet to be recieved by the listeners.
@@ -222,7 +223,7 @@ class PlayerInjector {
 		Integer id = MinecraftRegistry.getPacketToID().get(packet.getClass());
 
 		// Make sure we're listening
-		if (packetFilters.contains(id)) {	
+		if (id != null && sendingFilters.contains(id)) {
 			// A packet has been sent guys!
 			PacketContainer container = new PacketContainer(id, packet);
 			PacketEvent event = PacketEvent.fromServer(manager, container, player);
@@ -239,6 +240,11 @@ class PlayerInjector {
 		return packet;
 	}
 	
+	/**
+	 * Retrieve the current player's input stream.
+	 * @param cache - whether or not to cache the result of this method.
+	 * @return The player's input stream.
+	 */
 	public DataInputStream getInputStream(boolean cache) {
 		// Get the associated input stream
 		try {
@@ -246,16 +252,11 @@ class PlayerInjector {
 				return cachedInput;
 			
 			// Save to cache
-			cachedInput = (DataInputStream) FieldUtils.readField(inputField, networkManager.getOldValue(), true);
+			cachedInput = (DataInputStream) FieldUtils.readField(inputField, networkManager, true);
 			return cachedInput;
 			
 		} catch (IllegalAccessException e) {
 			throw new RuntimeException("Unable to read input stream.", e);
 		}
 	}
-	
-	public void cleanupAll() {
-		// Clean up
-		networkManager.revertValue();
-	}
 }

ProtocolLib/src/com/comphenix/protocol/injector/PrioritizedListener.java

@@ -0,0 +1,64 @@
+package com.comphenix.protocol.injector;
+
+import com.comphenix.protocol.events.ListenerPriority;
+import com.google.common.base.Objects;
+import com.google.common.primitives.Ints;
+
+/**
+ * Represents a listener with a priority.
+ * 
+ * @author Kristian
+ */
+public class PrioritizedListener<TListener> implements Comparable<PrioritizedListener<TListener>> {
+
+	private TListener listener;
+	private ListenerPriority priority;
+	
+	public PrioritizedListener(TListener listener, ListenerPriority priority) {
+		this.listener = listener;
+		this.priority = priority;
+	}
+
+	@Override
+	public int compareTo(PrioritizedListener<TListener> other) {
+		// This ensures that lower priority listeners are executed first
+		return Ints.compare(
+			this.getPriority().getSlot(),
+			other.getPriority().getSlot());
+	}
+	
+	// Note that this equals() method is NOT consistent with compareTo(). 
+	// But, it's a private class so who cares.
+	@SuppressWarnings("unchecked")
+	@Override
+	public boolean equals(Object obj) {
+		// We only care about the listener - priority itself should not make a difference
+	    if(obj instanceof PrioritizedListener){
+	        final PrioritizedListener<TListener> other = (PrioritizedListener<TListener>) obj;
+	        return Objects.equal(listener, other.listener);
+	    } else {
+	        return false;
+	    }
+	}
+	
+	@Override
+	public int hashCode() {
+		return Objects.hashCode(listener);
+	}
+	
+	/**
+	 * Retrieve the underlying listener.
+	 * @return Underlying listener.
+	 */
+	public TListener getListener() {
+		return listener;
+	}
+
+	/**
+	 * Retrieve the priority of this listener.
+	 * @return Listener priority.
+	 */
+	public ListenerPriority getPriority() {
+		return priority;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/ReadPacketModifier.java

@@ -1,11 +1,27 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.injector;
 
 import java.io.DataInputStream;
 import java.lang.reflect.Method;
+import java.util.Arrays;
 import java.util.WeakHashMap;
 
-import org.apache.commons.lang.ArrayUtils;
-
 import com.comphenix.protocol.events.PacketContainer;
 import com.comphenix.protocol.events.PacketEvent;
 
@@ -29,6 +45,23 @@ class ReadPacketModifier implements MethodInterceptor {
 		this.packetID = packetID;
 		this.packetInjector = packetInjector;
 	}
+	
+	/**
+	 * Remove any packet overrides.
+	 * @param packet - the packet to rever
+	 */
+	public void removeOverride(Packet packet) {
+		override.remove(packet);
+	}
+	
+	/**
+	 * Retrieve the packet that overrides the methods of the given packet.
+	 * @param packet - the given packet.
+	 * @return Overriden object.
+	 */
+	public Object getOverride(Packet packet) {
+		return override.get(packet);
+	}
 
 	@Override
 	public Object intercept(Object thisObj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
@@ -44,9 +77,14 @@ class ReadPacketModifier implements MethodInterceptor {
 		if (override.containsKey(thisObj)) {
 			Object overridenObject = override.get(thisObj);
 			
-			// Cancel EVERYTHING, including "processPacket"
-			if (overridenObject == null)
-				return null;
+			// This packet has been cancelled
+			if (overridenObject == null) {
+				// So, cancel all void methods
+				if (method.getReturnType().equals(Void.TYPE))
+					return null;
+				else // Revert to normal for everything else
+					overridenObject = thisObj;
+			}
 			
 			returnValue = proxy.invokeSuper(overridenObject, args);
 		} else {
@@ -55,11 +93,11 @@ class ReadPacketModifier implements MethodInterceptor {
 		
 		// Is this a readPacketData method?
 		if (returnValue == null && 
-				ArrayUtils.isEquals(method.getParameterTypes(), parameters)) {
+				Arrays.equals(method.getParameterTypes(), parameters)) {
 			
 			// We need this in order to get the correct player
 			DataInputStream input = (DataInputStream) args[0];
-			
+
 			// Let the people know
 			PacketContainer container = new PacketContainer(packetID, (Packet) thisObj);
 			PacketEvent event = packetInjector.packetRecieved(container, input);

ProtocolLib/src/com/comphenix/protocol/injector/ReplacedArrayList.java

@@ -0,0 +1,136 @@
+package com.comphenix.protocol.injector;
+
+import java.util.Collection;
+import java.util.List;
+
+import com.google.common.base.Objects;
+import com.google.common.collect.BiMap;
+import com.google.common.collect.ForwardingList;
+import com.google.common.collect.HashBiMap;
+
+/**
+ * Represents an array list that wraps another list, while automatically replacing one element with another.
+ * <p>
+ * The replaced elements can be recovered. 
+ * 
+ * @author Kristian
+ * @param <TKey> - type of the elements we're replacing.
+ */
+class ReplacedArrayList<TKey> extends ForwardingList<TKey> {
+	private BiMap<TKey, TKey> replaceMap = HashBiMap.create();
+	private List<TKey> underlyingList;
+	
+	public ReplacedArrayList(List<TKey> underlyingList) {
+		this.underlyingList = underlyingList;
+	}
+	
+	@Override
+	public boolean add(TKey element) {
+		if (replaceMap.containsKey(element)) {
+			return super.add(replaceMap.get(element));
+		} else {
+			return super.add(element);
+		}
+	}
+	
+	@Override
+	public void add(int index, TKey element) {
+		if (replaceMap.containsKey(element)) {
+			super.add(index, replaceMap.get(element));
+		} else {
+			super.add(index, element);
+		}
+	}
+	
+	@Override
+	public boolean addAll(Collection<? extends TKey> collection) {
+		int oldSize = size();
+		
+		for (TKey element : collection)
+			add(element);
+		return size() != oldSize;
+	}
+	
+	@Override
+	public boolean addAll(int index, Collection<? extends TKey> elements) {
+		int oldSize = size();
+		
+		for (TKey element : elements)
+			add(index++, element);
+		return size() != oldSize;
+	}
+	
+	@Override
+	protected List<TKey> delegate() {
+		return underlyingList;
+	}
+
+	/**
+	 * Add a replace rule.
+	 * <p>
+	 * This automatically replaces every existing element.
+	 * @param target - instance to find.
+	 * @param replacement - instance to replace with.
+	 */
+	public synchronized void addMapping(TKey target, TKey replacement) {
+		replaceMap.put(target, replacement);
+
+		// Replace existing elements
+		replaceAll(target, replacement);
+	}
+	
+	/**
+	 * Revert the given mapping.
+	 * @param target - the instance we replaced.
+	 */
+	public synchronized void removeMapping(TKey target) {
+		// Make sure the mapping exist
+		if (replaceMap.containsKey(target)) {
+			TKey replacement = replaceMap.get(target);
+			replaceMap.remove(target);
+	
+			// Revert existing elements
+			replaceAll(replacement, target);
+		}
+	}
+	
+	/**
+	 * Replace all instances of the given object.
+	 * @param find - object to find.
+	 * @param replace - object to replace it with.
+	 */
+	public synchronized void replaceAll(TKey find, TKey replace) {
+		for (int i = 0; i < underlyingList.size(); i++) {
+			if (Objects.equal(underlyingList.get(i), find))
+				underlyingList.set(i, replace);
+		}
+	}
+	
+	/**
+	 * Undo all replacements.
+	 */
+	public synchronized void revertAll() {
+		
+		// No need to do anything else
+		if (replaceMap.size() < 1)
+			return;
+		
+		BiMap<TKey, TKey> inverse = replaceMap.inverse();
+		
+		for (int i = 0; i < underlyingList.size(); i++) {
+			TKey replaced = underlyingList.get(i);
+			
+			if (inverse.containsKey(replaced)) {
+				underlyingList.set(i, inverse.get(replaced));
+			}
+		}
+		
+		replaceMap.clear();
+	}
+	
+	@Override
+	protected void finalize() throws Throwable {
+		revertAll();
+		super.finalize();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/injector/SortedPacketListenerList.java

@@ -0,0 +1,66 @@
+package com.comphenix.protocol.injector;
+
+import java.util.Collection;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import com.comphenix.protocol.concurrency.AbstractConcurrentListenerMultimap;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.events.PacketListener;
+
+/**
+ * Registry of synchronous packet listeners.
+ * 
+ * @author Kristian
+ */
+class SortedPacketListenerList extends AbstractConcurrentListenerMultimap<PacketListener> {
+	
+	/**
+	 * Invokes the given packet event for every registered listener.
+	 * @param logger - the logger that will be used to inform about listener exceptions.
+	 * @param event - the packet event to invoke.
+	 */
+	public void invokePacketRecieving(Logger logger, PacketEvent event) {
+		Collection<PrioritizedListener<PacketListener>> list = getListener(event.getPacketID());
+		
+		if (list == null)
+			return;
+
+		// The returned list is thread-safe
+		for (PrioritizedListener<PacketListener> element : list) {
+			try {
+				element.getListener().onPacketReceiving(event);
+			} catch (Throwable e) {
+				// Minecraft doesn't want your Exception.
+				logger.log(Level.SEVERE, 
+						"Exception occured in onPacketReceiving() for " + 
+							PacketAdapter.getPluginName(element.getListener()), e);
+			}
+		}
+	}
+	
+	/**
+	 * Invokes the given packet event for every registered listener.
+	 * @param logger - the logger that will be used to inform about listener exceptions.
+	 * @param event - the packet event to invoke.
+	 */
+	public void invokePacketSending(Logger logger, PacketEvent event) {
+		Collection<PrioritizedListener<PacketListener>> list = getListener(event.getPacketID());
+		
+		if (list == null)
+			return;
+		
+		for (PrioritizedListener<PacketListener> element : list) {
+			try {
+				element.getListener().onPacketSending(event);
+			} catch (Throwable e) {
+				// Minecraft doesn't want your Exception.
+				logger.log(Level.SEVERE, 
+						"Exception occured in onPacketSending() for " + 
+							PacketAdapter.getPluginName(element.getListener()), e);
+			}
+		}
+	}
+	
+}

ProtocolLib/src/com/comphenix/protocol/injector/StructureCache.java

@@ -1,15 +1,44 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.injector;
 
-import java.util.HashMap;
-import java.util.Map;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 import net.minecraft.server.Packet;
 
 import com.comphenix.protocol.reflect.StructureModifier;
+import com.comphenix.protocol.reflect.compiler.BackgroundCompiler;
+import com.comphenix.protocol.reflect.compiler.CompileListener;
+import com.comphenix.protocol.reflect.compiler.CompiledStructureModifier;
 
+/**
+ * Caches structure modifiers.
+ * @author Kristian
+ */
 public class StructureCache {
 	// Structure modifiers
-	private static Map<Integer, StructureModifier<Object>> structureModifiers = new HashMap<Integer, StructureModifier<Object>>();
+	private static ConcurrentMap<Integer, StructureModifier<Object>> structureModifiers = 
+			new ConcurrentHashMap<Integer, StructureModifier<Object>>();
+	
+	private static Set<Integer> compiling = new HashSet<Integer>();
 	
 	/**
 	 * Creates an empty Minecraft packet of the given ID.
@@ -32,13 +61,51 @@ public class StructureCache {
 	 * @return A structure modifier.
 	 */
 	public static StructureModifier<Object> getStructure(int id) {
+		// Compile structures by default
+		return getStructure(id, true);
+	}
+	
+	/**
+	 * Retrieve a cached structure modifier for the given packet id.
+	 * @param id - packet ID.
+	 * @param compile - whether or not to asynchronously compile the structure modifier.
+	 * @return A structure modifier.
+	 */
+	public static StructureModifier<Object> getStructure(int id, boolean compile) {
 		
 		StructureModifier<Object> result = structureModifiers.get(id);
-		
-		// Use the vanilla class definition
+
+		// We don't want to create this for every lookup
 		if (result == null) {
-			result = new StructureModifier<Object>(MinecraftRegistry.getPacketClassFromID(id, true));
-			structureModifiers.put(id, result);
+			// Use the vanilla class definition
+			final StructureModifier<Object> value = new StructureModifier<Object>(
+					MinecraftRegistry.getPacketClassFromID(id, true), Packet.class, true);
+			
+			result = structureModifiers.putIfAbsent(id, value);
+			
+			// We may end up creating multiple modifiers, but we'll agree on which to use
+			if (result == null) {
+				result = value;
+			}
+		}
+		
+		// Automatically compile the structure modifier
+		if (compile && !(result instanceof CompiledStructureModifier)) {
+			// Compilation is many orders of magnitude slower than synchronization
+			synchronized (compiling) {
+				final int idCopy = id;
+				final BackgroundCompiler compiler = BackgroundCompiler.getInstance();
+				
+				if (!compiling.contains(id) && compiler != null) {
+					compiler.scheduleCompilation(result, new CompileListener<Object>() {
+						@Override
+						public void onCompiled(StructureModifier<Object> compiledModifier) {
+							structureModifiers.put(idCopy, compiledModifier);
+						}
+					});
+					compiling.add(id);
+				}
+			}
 		}
 		
 		return result;

ProtocolLib/src/com/comphenix/protocol/metrics/Metrics.java

@@ -0,0 +1,648 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.protocol.metrics;
+
+/*
+ * Copyright 2011 Tyler Blair. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and contributors and should not be interpreted as representing official policies,
+ * either expressed or implied, of anybody else.
+ */
+
+import org.bukkit.Bukkit;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.configuration.InvalidConfigurationException;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.plugin.PluginDescriptionFile;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.UnsupportedEncodingException;
+import java.net.Proxy;
+import java.net.URL;
+import java.net.URLConnection;
+import java.net.URLEncoder;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.Set;
+import java.util.UUID;
+import java.util.logging.Level;
+
+/**
+ * <p>
+ * The metrics class obtains data about a plugin and submits statistics about it to the metrics backend.
+ * </p>
+ * <p>
+ * Public methods provided by this class:
+ * </p>
+ * <code>
+ * Graph createGraph(String name); <br/>
+ * void addCustomData(Metrics.Plotter plotter); <br/>
+ * void start(); <br/>
+ * </code>
+ */
+class Metrics {
+
+    /**
+     * The current revision number
+     */
+    private final static int REVISION = 5;
+
+    /**
+     * The base url of the metrics domain
+     */
+    private static final String BASE_URL = "http://mcstats.org";
+
+    /**
+     * The url used to report a server's status
+     */
+    private static final String REPORT_URL = "/report/%s";
+
+    /**
+     * The separator to use for custom data. This MUST NOT change unless you are hosting your own
+     * version of metrics and want to change it.
+     */
+    private static final String CUSTOM_DATA_SEPARATOR = "~~";
+
+    /**
+     * Interval of time to ping (in minutes)
+     */
+    private static final int PING_INTERVAL = 10;
+
+    /**
+     * The plugin this metrics submits for
+     */
+    private final Plugin plugin;
+
+    /**
+     * All of the custom graphs to submit to metrics
+     */
+    private final Set<Graph> graphs = Collections.synchronizedSet(new HashSet<Graph>());
+
+    /**
+     * The default graph, used for addCustomData when you don't want a specific graph
+     */
+    private final Graph defaultGraph = new Graph("Default");
+
+    /**
+     * The plugin configuration file
+     */
+    private final YamlConfiguration configuration;
+    
+    /**
+     * The plugin configuration file
+     */
+    private final File configurationFile;
+
+    /**
+     * Unique server id
+     */
+    private final String guid;
+
+    /**
+     * Lock for synchronization
+     */
+    private final Object optOutLock = new Object();
+
+    /**
+     * Id of the scheduled task
+     */
+    private volatile int taskId = -1;
+
+    public Metrics(final Plugin plugin) throws IOException {
+        if (plugin == null) {
+            throw new IllegalArgumentException("Plugin cannot be null");
+        }
+
+        this.plugin = plugin;
+
+        // load the config
+        configurationFile = getConfigFile();
+        configuration = YamlConfiguration.loadConfiguration(configurationFile);
+
+        // add some defaults
+        configuration.addDefault("opt-out", false);
+        configuration.addDefault("guid", UUID.randomUUID().toString());
+
+        // Do we need to create the file?
+        if (configuration.get("guid", null) == null) {
+            configuration.options().header("http://mcstats.org").copyDefaults(true);
+            configuration.save(configurationFile);
+        }
+
+        // Load the guid then
+        guid = configuration.getString("guid");
+    }
+
+    /**
+     * Construct and create a Graph that can be used to separate specific plotters to their own graphs
+     * on the metrics website. Plotters can be added to the graph object returned.
+     *
+     * @param name The name of the graph
+     * @return Graph object created. Will never return NULL under normal circumstances unless bad parameters are given
+     */
+    public Graph createGraph(final String name) {
+        if (name == null) {
+            throw new IllegalArgumentException("Graph name cannot be null");
+        }
+
+        // Construct the graph object
+        final Graph graph = new Graph(name);
+
+        // Now we can add our graph
+        graphs.add(graph);
+
+        // and return back
+        return graph;
+    }
+
+    /**
+     * Add a Graph object to Metrics that represents data for the plugin that should be sent to the backend
+     *
+     * @param graph The name of the graph
+     */
+    public void addGraph(final Graph graph) {
+        if (graph == null) {
+            throw new IllegalArgumentException("Graph cannot be null");
+        }
+
+        graphs.add(graph);
+    }
+
+    /**
+     * Adds a custom data plotter to the default graph
+     *
+     * @param plotter The plotter to use to plot custom data
+     */
+    public void addCustomData(final Plotter plotter) {
+        if (plotter == null) {
+            throw new IllegalArgumentException("Plotter cannot be null");
+        }
+
+        // Add the plotter to the graph o/
+        defaultGraph.addPlotter(plotter);
+
+        // Ensure the default graph is included in the submitted graphs
+        graphs.add(defaultGraph);
+    }
+
+    /**
+     * Start measuring statistics. This will immediately create an async repeating task as the plugin and send
+     * the initial data to the metrics backend, and then after that it will post in increments of
+     * PING_INTERVAL * 1200 ticks.
+     *
+     * @return True if statistics measuring is running, otherwise false.
+     */
+    public boolean start() {
+        synchronized (optOutLock) {
+            // Did we opt out?
+            if (isOptOut()) {
+                return false;
+            }
+
+            // Is metrics already running?
+            if (taskId >= 0) {
+                return true;
+            }
+
+            // Begin hitting the server with glorious data
+            taskId = plugin.getServer().getScheduler().scheduleAsyncRepeatingTask(plugin, new Runnable() {
+
+                private boolean firstPost = true;
+
+                public void run() {
+                    try {
+                        // This has to be synchronized or it can collide with the disable method.
+                        synchronized (optOutLock) {
+                            // Disable Task, if it is running and the server owner decided to opt-out
+                            if (isOptOut() && taskId > 0) {
+                                plugin.getServer().getScheduler().cancelTask(taskId);
+                                taskId = -1;
+                                // Tell all plotters to stop gathering information.
+                                for (Graph graph : graphs){
+                                    graph.onOptOut();
+                                }
+                            }
+                        }
+
+                        // We use the inverse of firstPost because if it is the first time we are posting,
+                        // it is not a interval ping, so it evaluates to FALSE
+                        // Each time thereafter it will evaluate to TRUE, i.e PING!
+                        postPlugin(!firstPost);
+
+                        // After the first post we set firstPost to false
+                        // Each post thereafter will be a ping
+                        firstPost = false;
+                    } catch (IOException e) {
+                        Bukkit.getLogger().log(Level.INFO, "[Metrics] " + e.getMessage());
+                    }
+                }
+            }, 0, PING_INTERVAL * 1200);
+
+            return true;
+        }
+    }
+
+    /**
+     * Has the server owner denied plugin metrics?
+     *
+     * @return true if metrics should be opted out of it
+     */
+    public boolean isOptOut() {
+        synchronized(optOutLock) {
+            try {
+                // Reload the metrics file
+                configuration.load(getConfigFile());
+            } catch (IOException ex) {
+                Bukkit.getLogger().log(Level.INFO, "[Metrics] " + ex.getMessage());
+                return true;
+            } catch (InvalidConfigurationException ex) {
+                Bukkit.getLogger().log(Level.INFO, "[Metrics] " + ex.getMessage());
+                return true;
+            }
+            return configuration.getBoolean("opt-out", false);
+        }
+    }
+
+    /**
+    * Enables metrics for the server by setting "opt-out" to false in the config file and starting the metrics task.
+    *
+    * @throws IOException
+    */
+    public void enable() throws IOException {
+        // This has to be synchronized or it can collide with the check in the task.
+        synchronized (optOutLock) {
+        	// Check if the server owner has already set opt-out, if not, set it.
+        	if (isOptOut()) {
+        		configuration.set("opt-out", false);
+        		configuration.save(configurationFile);
+        	}
+
+        	// Enable Task, if it is not running
+        	if (taskId < 0) {
+        		start();
+        	}
+        }
+    }
+
+    /**
+     * Disables metrics for the server by setting "opt-out" to true in the config file and canceling the metrics task.
+     *
+     * @throws IOException
+     */
+    public void disable() throws IOException {
+        // This has to be synchronized or it can collide with the check in the task.
+        synchronized (optOutLock) {
+            // Check if the server owner has already set opt-out, if not, set it.
+            if (!isOptOut()) {
+                configuration.set("opt-out", true);
+                configuration.save(configurationFile);
+            }
+
+            // Disable Task, if it is running
+            if (taskId > 0) {
+                this.plugin.getServer().getScheduler().cancelTask(taskId);
+                taskId = -1;
+            }
+        }
+    }
+
+    /**
+     * Gets the File object of the config file that should be used to store data such as the GUID and opt-out status
+     *
+     * @return the File object for the config file
+     */
+    public File getConfigFile() {
+        // I believe the easiest way to get the base folder (e.g craftbukkit set via -P) for plugins to use
+        // is to abuse the plugin object we already have
+        // plugin.getDataFolder() => base/plugins/PluginA/
+        // pluginsFolder => base/plugins/
+        // The base is not necessarily relative to the startup directory.
+        File pluginsFolder = plugin.getDataFolder().getParentFile();
+
+        // return => base/plugins/PluginMetrics/config.yml
+        return new File(new File(pluginsFolder, "PluginMetrics"), "config.yml");
+    }
+
+    /**
+     * Generic method that posts a plugin to the metrics website
+     */
+    private void postPlugin(final boolean isPing) throws IOException {
+        // The plugin's description file containg all of the plugin data such as name, version, author, etc
+        final PluginDescriptionFile description = plugin.getDescription();
+
+        // Construct the post data
+        final StringBuilder data = new StringBuilder();
+        data.append(encode("guid")).append('=').append(encode(guid));
+        encodeDataPair(data, "version", description.getVersion());
+        encodeDataPair(data, "server", Bukkit.getVersion());
+        encodeDataPair(data, "players", Integer.toString(Bukkit.getServer().getOnlinePlayers().length));
+        encodeDataPair(data, "revision", String.valueOf(REVISION));
+
+        // If we're pinging, append it
+        if (isPing) {
+            encodeDataPair(data, "ping", "true");
+        }
+
+        // Acquire a lock on the graphs, which lets us make the assumption we also lock everything
+        // inside of the graph (e.g plotters)
+        synchronized (graphs) {
+            final Iterator<Graph> iter = graphs.iterator();
+
+            while (iter.hasNext()) {
+                final Graph graph = iter.next();
+
+                for (Plotter plotter : graph.getPlotters()) {
+                    // The key name to send to the metrics server
+                    // The format is C-GRAPHNAME-PLOTTERNAME where separator - is defined at the top
+                    // Legacy (R4) submitters use the format Custom%s, or CustomPLOTTERNAME
+                    final String key = String.format("C%s%s%s%s", CUSTOM_DATA_SEPARATOR, graph.getName(), CUSTOM_DATA_SEPARATOR, plotter.getColumnName());
+
+                    // The value to send, which for the foreseeable future is just the string
+                    // value of plotter.getValue()
+                    final String value = Integer.toString(plotter.getValue());
+
+                    // Add it to the http post data :)
+                    encodeDataPair(data, key, value);
+                }
+            }
+        }
+
+        // Create the url
+        URL url = new URL(BASE_URL + String.format(REPORT_URL, encode(plugin.getDescription().getName())));
+
+        // Connect to the website
+        URLConnection connection;
+
+        // Mineshafter creates a socks proxy, so we can safely bypass it
+        // It does not reroute POST requests so we need to go around it
+        if (isMineshafterPresent()) {
+            connection = url.openConnection(Proxy.NO_PROXY);
+        } else {
+            connection = url.openConnection();
+        }
+
+        connection.setDoOutput(true);
+
+        // Write the data
+        final OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
+        writer.write(data.toString());
+        writer.flush();
+
+        // Now read the response
+        final BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
+        final String response = reader.readLine();
+
+        // close resources
+        writer.close();
+        reader.close();
+
+        if (response == null || response.startsWith("ERR")) {
+            throw new IOException(response); //Throw the exception
+        } else {
+            // Is this the first update this hour?
+            if (response.contains("OK This is your first update this hour")) {
+                synchronized (graphs) {
+                    final Iterator<Graph> iter = graphs.iterator();
+
+                    while (iter.hasNext()) {
+                        final Graph graph = iter.next();
+
+                        for (Plotter plotter : graph.getPlotters()) {
+                            plotter.reset();
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Check if mineshafter is present. If it is, we need to bypass it to send POST requests
+     *
+     * @return true if mineshafter is installed on the server
+     */
+    private boolean isMineshafterPresent() {
+        try {
+            Class.forName("mineshafter.MineServer");
+            return true;
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    /**
+     * <p>Encode a key/value data pair to be used in a HTTP post request. This INCLUDES a & so the first
+     * key/value pair MUST be included manually, e.g:</p>
+     * <code>
+     * StringBuffer data = new StringBuffer();
+     * data.append(encode("guid")).append('=').append(encode(guid));
+     * encodeDataPair(data, "version", description.getVersion());
+     * </code>
+     *
+     * @param buffer the stringbuilder to append the data pair onto
+     * @param key the key value
+     * @param value the value
+     */
+    private static void encodeDataPair(final StringBuilder buffer, final String key, final String value) throws UnsupportedEncodingException {
+        buffer.append('&').append(encode(key)).append('=').append(encode(value));
+    }
+
+    /**
+     * Encode text as UTF-8
+     *
+     * @param text the text to encode
+     * @return the encoded text, as UTF-8
+     */
+    private static String encode(final String text) throws UnsupportedEncodingException {
+        return URLEncoder.encode(text, "UTF-8");
+    }
+
+    /**
+     * Represents a custom graph on the website
+     */
+    public static class Graph {
+
+        /**
+         * The graph's name, alphanumeric and spaces only :)
+         * If it does not comply to the above when submitted, it is rejected
+         */
+        private final String name;
+
+        /**
+         * The set of plotters that are contained within this graph
+         */
+        private final Set<Plotter> plotters = new LinkedHashSet<Plotter>();
+
+        private Graph(final String name) {
+            this.name = name;
+        }
+
+        /**
+         * Gets the graph's name
+         *
+         * @return the Graph's name
+         */
+        public String getName() {
+            return name;
+        }
+
+        /**
+         * Add a plotter to the graph, which will be used to plot entries
+         *
+         * @param plotter the plotter to add to the graph
+         */
+        public void addPlotter(final Plotter plotter) {
+            plotters.add(plotter);
+        }
+
+        /**
+         * Remove a plotter from the graph
+         *
+         * @param plotter the plotter to remove from the graph
+         */
+        public void removePlotter(final Plotter plotter) {
+            plotters.remove(plotter);
+        }
+
+        /**
+         * Gets an <b>unmodifiable</b> set of the plotter objects in the graph
+         *
+         * @return an unmodifiable {@link Set} of the plotter objects
+         */
+        public Set<Plotter> getPlotters() {
+            return Collections.unmodifiableSet(plotters);
+        }
+
+        @Override
+        public int hashCode() {
+            return name.hashCode();
+        }
+
+        @Override
+        public boolean equals(final Object object) {
+            if (!(object instanceof Graph)) {
+                return false;
+            }
+
+            final Graph graph = (Graph) object;
+            return graph.name.equals(name);
+        }
+
+        /**
+         * Called when the server owner decides to opt-out of Metrics while the server is running.
+         */
+        protected void onOptOut() {
+        }
+
+    }
+
+    /**
+     * Interface used to collect custom data for a plugin
+     */
+    public static abstract class Plotter {
+
+        /**
+         * The plot's name
+         */
+        private final String name;
+
+        /**
+         * Construct a plotter with the default plot name
+         */
+        public Plotter() {
+            this("Default");
+        }
+
+        /**
+         * Construct a plotter with a specific plot name
+         *
+         * @param name the name of the plotter to use, which will show up on the website
+         */
+        public Plotter(final String name) {
+            this.name = name;
+        }
+
+        /**
+         * Get the current value for the plotted point. Since this function defers to an external function
+         * it may or may not return immediately thus cannot be guaranteed to be thread friendly or safe.
+         * This function can be called from any thread so care should be taken when accessing resources
+         * that need to be synchronized.
+         *
+         * @return the current value for the point to be plotted.
+         */
+        public abstract int getValue();
+
+        /**
+         * Get the column name for the plotted point
+         *
+         * @return the plotted point's column name
+         */
+        public String getColumnName() {
+            return name;
+        }
+
+        /**
+         * Called after the website graphs have been updated
+         */
+        public void reset() {
+        }
+
+        @Override
+        public int hashCode() {
+            return getColumnName().hashCode();
+        }
+
+        @Override
+        public boolean equals(final Object object) {
+            if (!(object instanceof Plotter)) {
+                return false;
+            }
+
+            final Plotter plotter = (Plotter) object;
+            return plotter.name.equals(name) && plotter.getValue() == getValue();
+        }
+
+    }
+}

ProtocolLib/src/com/comphenix/protocol/metrics/Statistics.java

@@ -0,0 +1,81 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.protocol.metrics;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.bukkit.plugin.Plugin;
+
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketListener;
+import com.comphenix.protocol.metrics.Metrics.Graph;
+
+public class Statistics {
+
+	// Metrics
+	private Metrics metrics;
+	
+	public Statistics(Plugin plugin) throws IOException {
+		metrics = new Metrics(plugin);
+		metrics.start();
+		
+		// Determine who is using this library
+		addPluginUserGraph(metrics);
+	}
+	
+	private void addPluginUserGraph(Metrics metrics) {
+	
+		Graph pluginUsers = metrics.createGraph("Plugin Users");
+		
+		for (Map.Entry<String, Integer> entry : getPluginUsers(ProtocolLibrary.getProtocolManager()).entrySet()) {
+			final int count = entry.getValue();
+			
+			// Plot plugins of this type
+			pluginUsers.addPlotter(new Metrics.Plotter(entry.getKey()) {
+				@Override
+				public int getValue() {
+					return count;
+				}
+			});
+		}
+	}
+	
+	// Retrieve loaded plugins
+	private Map<String, Integer> getPluginUsers(ProtocolManager manager) {
+		
+		Map<String, Integer> users = new HashMap<String, Integer>();
+			
+		for (PacketListener listener : manager.getPacketListeners()) {
+			
+			String name = PacketAdapter.getPluginName(listener);
+			
+			// Increment occurence
+			if (!users.containsKey(name)) {
+				users.put(name, 1);
+			} else {
+				users.put(name, users.get(name) + 1);
+			}
+		}
+		
+		return users;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/EquivalentConverter.java

@@ -1,3 +1,20 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.reflect;
 
 /**
@@ -9,4 +26,5 @@ package com.comphenix.protocol.reflect;
 public interface EquivalentConverter<TType> {
 	public TType getSpecific(Object generic);
 	public Object getGeneric(TType specific);
+	public Class<TType> getSpecificType();
 }

ProtocolLib/src/com/comphenix/protocol/reflect/FieldAccessException.java

@@ -0,0 +1,51 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.protocol.reflect;
+
+/**
+ * Invoked when a field is inaccessible due to security limitations, or when it simply doesn't exist.
+ * 
+ * @author Kristian
+ */
+public class FieldAccessException extends Exception {
+
+	/**
+	 * Generated by Eclipse.
+	 */
+	private static final long serialVersionUID = 1911011681494034617L;
+
+	public FieldAccessException() {
+		super();
+	}
+	
+	public FieldAccessException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	public FieldAccessException(String message) {
+		super(message);
+	}
+
+	public FieldAccessException(Throwable cause) {
+		super(cause);
+	}
+	
+	public static FieldAccessException fromFormat(String message, Object... params) {
+		return new FieldAccessException(String.format(message, params));
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/FieldUtils.java

@@ -21,9 +21,9 @@ import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Field;
 import java.lang.reflect.Member;
 import java.lang.reflect.Modifier;
+import java.util.ArrayList;
 import java.util.Iterator;
-
-import org.apache.commons.lang.ClassUtils;
+import java.util.List;
 
 /**
  * Utilities for working with fields by reflection. Adapted and refactored from
@@ -119,11 +119,11 @@ public class FieldUtils {
 			}
 		}
 		// check the public interface case. This must be manually searched for
-		// incase there is a public supersuperclass field hidden by a
+		// in case there is a public supersuperclass field hidden by a
 		// private/package
 		// superclass field.
 		Field match = null;
-		for (Iterator intf = ClassUtils.getAllInterfaces(cls).iterator(); intf.hasNext();) {
+		for (Iterator intf = getAllInterfaces(cls).iterator(); intf.hasNext();) {
 			try {
 				Field test = ((Class) intf.next()).getField(fieldName);
 				if (match != null) {
@@ -138,6 +138,44 @@ public class FieldUtils {
 		}
 		return match;
 	}
+	
+    /**
+     * <p>Gets a <code>List</code> of all interfaces implemented by the given
+     * class and its superclasses.</p>
+     *
+     * <p>The order is determined by looking through each interface in turn as
+     * declared in the source file and following its hierarchy up. Then each
+     * superclass is considered in the same way. Later duplicates are ignored,
+     * so the order is maintained.</p>
+     *
+     * @param cls  the class to look up, may be <code>null</code>
+     * @return the <code>List</code> of interfaces in order,
+     *  <code>null</code> if null input
+     */
+    private static List getAllInterfaces(Class cls) {
+        if (cls == null) {
+            return null;
+        }
+        List<Class> list = new ArrayList<Class>();
+        
+        while (cls != null) {
+            Class[] interfaces = cls.getInterfaces();
+            for (int i = 0; i < interfaces.length; i++) {
+                if (list.contains(interfaces[i]) == false) {
+                    list.add(interfaces[i]);
+                }
+                List superInterfaces = getAllInterfaces(interfaces[i]);
+                for (Iterator it = superInterfaces.iterator(); it.hasNext();) {
+                    Class intface = (Class) it.next();
+                    if (list.contains(intface) == false) {
+                        list.add(intface);
+                    }
+                }
+            }
+            cls = cls.getSuperclass();
+        }
+        return list;
+    }
 
 	/**
 	 * Read an accessible static Field.

ProtocolLib/src/com/comphenix/protocol/reflect/FuzzyReflection.java

@@ -1,13 +1,31 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.reflect;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
 import java.util.regex.Pattern;
 
-import org.apache.commons.lang.ArrayUtils;
-
 /**
  * Retrieves fields and methods by signature, not just name.
  * 
@@ -80,6 +98,7 @@ public class FuzzyReflection {
 	 * Retrieves a method by looking at its name.
 	 * @param nameRegex -  regular expression that will match method names.
 	 * @return The first method that satisfies the regular expression.
+	 * @throws RuntimeException If the method cannot be found.
 	 */
 	public Method getMethodByName(String nameRegex) {
 		
@@ -106,7 +125,7 @@ public class FuzzyReflection {
 		
 		// Find the correct method to call
 		for (Method method : getMethods()) {
-			if (ArrayUtils.isEquals(method.getParameterTypes(), args)) {
+			if (Arrays.equals(method.getParameterTypes(), args)) {
 				return method;
 			}
 		}
@@ -115,6 +134,86 @@ public class FuzzyReflection {
 		throw new RuntimeException("Unable to find " + name + " in " + source.getName());
 	}
 	
+	/**
+	 * Retrieves a method by looking at the parameter types and return type only.
+	 * @param name - potential name of the method. Only used by the error mechanism.
+	 * @param returnType - return type of the method to find.
+	 * @param args - parameter types of the method to find.
+	 * @return The first method that satisfies the parameter types.
+	 */
+	public Method getMethodByParameters(String name, Class<?> returnType, Class<?>[] args) {
+		// Find the correct method to call
+		List<Method> methods = getMethodListByParameters(returnType, args);
+		
+		if (methods.size() > 0) {
+			return methods.get(0);
+		} else {
+			// That sucks
+			throw new RuntimeException("Unable to find " + name + " in " + source.getName());
+		}
+	}
+	
+	/**
+	 * Retrieves a method by looking at the parameter types and return type only.
+	 * @param name - potential name of the method. Only used by the error mechanism.
+	 * @param returnType - regular expression matching the return type of the method to find.
+	 * @param args - regular expressions of the matching parameter types.
+	 * @return The first method that satisfies the parameter types.
+	 */
+	public Method getMethodByParameters(String name, String returnTypeRegex, String[] argsRegex) {
+	
+		Pattern match = Pattern.compile(returnTypeRegex);
+		Pattern[] argMatch = new Pattern[argsRegex.length];
+		
+		for (int i = 0; i < argsRegex.length; i++) {
+			argMatch[i] = Pattern.compile(argsRegex[i]);
+		}
+		
+		// Find the correct method to call
+		for (Method method : getMethods()) {
+			if (match.matcher(method.getReturnType().getName()).matches()) {
+				if (matchParameters(argMatch, method.getParameterTypes()))
+					return method;
+			}
+		}
+		
+		// That sucks
+		throw new RuntimeException("Unable to find " + name + " in " + source.getName());
+	}
+	
+	private boolean matchParameters(Pattern[] parameterMatchers, Class<?>[] argTypes) {
+		if (parameterMatchers.length != argTypes.length)
+			throw new IllegalArgumentException("Arrays must have the same cardinality.");
+		
+		// Check types against the regular expressions
+		for (int i = 0; i < argTypes.length; i++) {
+			if (!parameterMatchers[i].matcher(argTypes[i].getName()).matches())
+				return false;
+		}
+		
+		return true;
+	}
+	
+	/**
+	 * Retrieves every method that has the given parameter types and return type.
+	 * @param returnType - return type of the method to find.
+	 * @param args - parameter types of the method to find.
+	 * @return Every method that satisfies the given constraints.
+	 */
+	public List<Method> getMethodListByParameters(Class<?> returnType, Class<?>[] args) {
+	
+		List<Method> methods = new ArrayList<Method>();
+		
+		// Find the correct method to call
+		for (Method method : getMethods()) {
+			if (method.getReturnType().equals(returnType) && Arrays.equals(method.getParameterTypes(), args)) {
+				methods.add(method);
+			}
+		}
+		
+		return methods;
+	}
+	
 	/**
 	 * Retrieves a field by name.
 	 * @param nameRegex - regular expression that will match a field name.
@@ -136,6 +235,46 @@ public class FuzzyReflection {
 									nameRegex + " in " + source.getName());
 	}
 	
+	/**
+	 * Retrieves the first field with a type equal to or more specific to the given type.
+	 * @param name - name the field probably is given. This will only be used in the error message.
+	 * @param type - type of the field to find.
+	 * @return The first field with a type that is an instance of the given type.
+	 */
+	public Field getFieldByType(String name, Class<?> type) {
+		
+		List<Field> fields = getFieldListByType(type);
+		
+		if (fields.size() > 0) {
+			return fields.get(0);
+		} else {
+			// Looks like we're outdated. Too bad.
+			throw new RuntimeException(String.format("Unable to find a field %s with the type %s in %s",
+					name, type.getName(), source.getName())
+			);
+		}
+	}
+	
+	/**
+	 * Retrieves every field with a type equal to or more specific to the given type.
+	 * @param type - type of the fields to find.
+	 * @return Every field with a type that is an instance of the given type.
+	 */
+	public List<Field> getFieldListByType(Class<?> type) {
+		
+		List<Field> fields = new ArrayList<Field>();
+		
+		// Field with a compatible type
+		for (Field field : getFields()) {
+			// A assignable from B -> B instanceOf A
+			if (type.isAssignableFrom(field.getType())) {
+				fields.add(field);
+			}
+		}
+		
+		return fields;
+	}
+	
 	/**
 	 * Retrieves a field by type.
 	 * <p>
@@ -163,6 +302,37 @@ public class FuzzyReflection {
 									typeRegex + " in " + source.getName());
 	}
 	
+	/**
+	 * Retrieves a field by type.
+	 * <p>
+	 * Note that the type is matched using the full canonical representation, i.e.: 
+	 * <ul>
+	 *     <li>java.util.List</li>
+	 *     <li>net.comphenix.xp.ExperienceMod</li>
+	 * </ul>
+	 * @param typeRegex - regular expression that will match the field type.
+	 * @param ignored - types to ignore.
+	 * @return The first field with a type that matches the given regular expression.
+	 */
+	@SuppressWarnings("rawtypes")
+	public Field getFieldByType(String typeRegex, Set<Class> ignored) {
+		
+		Pattern match = Pattern.compile(typeRegex);
+		
+		// Like above, only here we test the field type
+		for (Field field : getFields()) {
+			Class type = field.getType();
+			
+			if (!ignored.contains(type) && match.matcher(type.getName()).matches()) {
+				return field;
+			}
+		}
+		
+		// Looks like we're outdated. Too bad.
+		throw new RuntimeException("Unable to find a field with the type " + 
+									typeRegex + " in " + source.getName());
+	}
+	
 	/**
 	 * Retrieves all private and public fields in declared order (after JDK 1.5).
 	 * @return Every field.

ProtocolLib/src/com/comphenix/protocol/reflect/IntEnum.java

@@ -0,0 +1,79 @@
+package com.comphenix.protocol.reflect;
+
+import java.lang.reflect.Field;
+
+import com.google.common.collect.BiMap;
+import com.google.common.collect.HashBiMap;
+
+/**
+ * Represents a traditional int field enum.
+ * 
+ * @author Kristian
+ */
+public class IntEnum {
+
+	// Used to convert between IDs and names
+	protected BiMap<Integer, String> members = HashBiMap.create();
+	
+	/**
+	 * Registers every declared integer field.
+	 */
+	public IntEnum() {
+		registerAll();
+	}
+	
+	/**
+	 * Registers every public int field as a member.
+	 */
+	protected void registerAll() {
+		try {
+			// Register every int field
+			for (Field entry : this.getClass().getFields()) {
+				if (entry.getType().equals(int.class)) {
+					registerMember(entry.getInt(this), entry.getName());
+				}
+			}
+		
+		} catch (IllegalArgumentException e) {
+			e.printStackTrace();
+		} catch (IllegalAccessException e) {
+			e.printStackTrace();
+		}
+	}
+	
+	/**
+	 * Registers a member.
+	 * @param id - id of member.
+	 * @param name - name of member.
+	 */
+	protected void registerMember(int id, String name) {
+		members.put(id, name);
+	}
+	
+	/**
+	 * Determines whether or not the given member exists.
+	 * @param id - the ID of the member to find.
+	 * @return TRUE if a member with the given ID exists, FALSE otherwise.
+	 */
+	public boolean hasMember(int id) {
+		return members.containsKey(id);
+	}
+	
+	/**
+	 * Retrieve the ID of the member with the given name.
+	 * @param name - name of member to retrieve.
+	 * @return ID of the member, or NULL if not found.
+	 */
+	public Integer valueOf(String name) {
+		return members.inverse().get(name);
+	}
+	
+	/**
+	 * Retrieve the name of the member with the given id.
+	 * @param id - id of the member to retrieve.
+	 * @return Declared name of the member, or NULL if not found.
+	 */
+	public String getDeclaredName(Integer id) {
+		return members.get(id);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/PrimitiveUtils.java

@@ -0,0 +1,124 @@
+package com.comphenix.protocol.reflect;
+
+/*
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Type;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Contains static utility methods pertaining to primitive types and their
+ * corresponding wrapper types.
+ * 
+ * @author Kevin Bourrillion
+ */
+public final class PrimitiveUtils {
+	private PrimitiveUtils() {
+	}
+
+	/** A map from primitive types to their corresponding wrapper types. */
+	private static final Map<Class<?>, Class<?>> PRIMITIVE_TO_WRAPPER_TYPE;
+
+	/** A map from wrapper types to their corresponding primitive types. */
+	private static final Map<Class<?>, Class<?>> WRAPPER_TO_PRIMITIVE_TYPE;
+
+	// Sad that we can't use a BiMap. :(
+	static {
+		Map<Class<?>, Class<?>> primToWrap = new HashMap<Class<?>, Class<?>>(16);
+		Map<Class<?>, Class<?>> wrapToPrim = new HashMap<Class<?>, Class<?>>(16);
+
+		add(primToWrap, wrapToPrim, boolean.class, Boolean.class);
+		add(primToWrap, wrapToPrim, byte.class, Byte.class);
+		add(primToWrap, wrapToPrim, char.class, Character.class);
+		add(primToWrap, wrapToPrim, double.class, Double.class);
+		add(primToWrap, wrapToPrim, float.class, Float.class);
+		add(primToWrap, wrapToPrim, int.class, Integer.class);
+		add(primToWrap, wrapToPrim, long.class, Long.class);
+		add(primToWrap, wrapToPrim, short.class, Short.class);
+		add(primToWrap, wrapToPrim, void.class, Void.class);
+
+		PRIMITIVE_TO_WRAPPER_TYPE = Collections.unmodifiableMap(primToWrap);
+		WRAPPER_TO_PRIMITIVE_TYPE = Collections.unmodifiableMap(wrapToPrim);
+	}
+
+	private static void add(Map<Class<?>, Class<?>> forward,
+			Map<Class<?>, Class<?>> backward, Class<?> key, Class<?> value) {
+		forward.put(key, value);
+		backward.put(value, key);
+	}
+
+	/**
+	 * Returns true if this type is a primitive.
+	 */
+	public static boolean isPrimitive(Type type) {
+		return PRIMITIVE_TO_WRAPPER_TYPE.containsKey(type);
+	}
+
+	/**
+	 * Returns {@code true} if {@code type} is one of the nine primitive-wrapper
+	 * types, such as {@link Integer}.
+	 * 
+	 * @see Class#isPrimitive
+	 */
+	public static boolean isWrapperType(Type type) {
+		return WRAPPER_TO_PRIMITIVE_TYPE.containsKey(checkNotNull(type));
+	}
+
+	/**
+	 * Returns the corresponding wrapper type of {@code type} if it is a
+	 * primitive type; otherwise returns {@code type} itself. Idempotent.
+	 * 
+	 * <pre>
+	 *     wrap(int.class) == Integer.class
+	 *     wrap(Integer.class) == Integer.class
+	 *     wrap(String.class) == String.class
+	 * </pre>
+	 */
+	public static <T> Class<T> wrap(Class<T> type) {
+		// cast is safe: long.class and Long.class are both of type Class<Long>
+		@SuppressWarnings("unchecked")
+		Class<T> wrapped = (Class<T>) PRIMITIVE_TO_WRAPPER_TYPE
+				.get(checkNotNull(type));
+		return (wrapped == null) ? type : wrapped;
+	}
+
+	/**
+	 * Returns the corresponding primitive type of {@code type} if it is a
+	 * wrapper type; otherwise returns {@code type} itself. Idempotent.
+	 * 
+	 * <pre>
+	 *     unwrap(Integer.class) == int.class
+	 *     unwrap(int.class) == int.class
+	 *     unwrap(String.class) == String.class
+	 * </pre>
+	 */
+	public static <T> Class<T> unwrap(Class<T> type) {
+		// cast is safe: long.class and Long.class are both of type Class<Long>
+		@SuppressWarnings("unchecked")
+		Class<T> unwrapped = (Class<T>) WRAPPER_TO_PRIMITIVE_TYPE
+				.get(checkNotNull(type));
+		return (unwrapped == null) ? type : unwrapped;
+	}
+	
+	public static <T> T checkNotNull(T obj) {
+		if (obj == null) {
+			throw new NullPointerException();
+		}
+		return obj;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/StructureModifier.java

@@ -1,3 +1,20 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.reflect;
 
 import java.lang.reflect.Field;
@@ -6,66 +23,133 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
+import com.comphenix.protocol.reflect.compiler.BackgroundCompiler;
+import com.comphenix.protocol.reflect.instances.DefaultInstances;
 import com.google.common.base.Function;
+import com.google.common.collect.ImmutableList;
 
-import net.minecraft.server.Packet;
-
+/**
+ * Provides list-oriented access to the fields of a Minecraft packet.
+ * <p>
+ * Implemented by using reflection. Use a CompiledStructureModifier, if speed is essential.
+ * 
+ * @author Kristian
+ * @param <TField> Type of the fields to retrieve.
+ */
 @SuppressWarnings("rawtypes")
 public class StructureModifier<TField> {
-
+	
 	// Object and its type
-	private Class targetType;
-	private Object target;
+	protected Class targetType;
+	protected Object target;
 	
 	// Converter. May be NULL.
-	private EquivalentConverter<TField> converter;
+	protected EquivalentConverter<TField> converter;
 	
 	// The fields to read in order
-	private Class fieldType;
-	private List<Field> data = new ArrayList<Field>();
+	protected Class fieldType;
+	protected List<Field> data = new ArrayList<Field>();
+	
+	// Improved default values
+	protected Map<Field, Integer> defaultFields;
 	
 	// Cache of previous types
-	private Map<Class, StructureModifier> subtypeCache;
+	protected Map<Class, StructureModifier> subtypeCache;
 	
-	public StructureModifier(Class targetType) {
-		this(targetType, Object.class, getFields(targetType), null, new HashMap<Class, StructureModifier>());
+	// Whether or subclasses should handle conversion
+	protected boolean customConvertHandling;
+	
+	/**
+	 * Creates a structure modifier.
+	 * @param targetType - the structure to modify.
+	 * @param superclassExclude - a superclass to exclude.
+	 * @param requireDefault - whether or not we will be using writeDefaults().
+	 */
+	public StructureModifier(Class targetType, Class superclassExclude, boolean requireDefault) {
+		List<Field> fields = getFields(targetType, superclassExclude);
+		Map<Field, Integer> defaults = requireDefault ? generateDefaultFields(fields) : new HashMap<Field, Integer>();
+		
+		initialize(targetType, Object.class, fields, defaults, null, new ConcurrentHashMap<Class, StructureModifier>());
 	}
 	
-	private StructureModifier(Class targetType, Class fieldType, List<Field> data, 
-							  EquivalentConverter<TField> converter, Map<Class, StructureModifier> subTypeCache) {
+	/**
+	 * Consumers of this method should call "initialize".
+	 */
+	protected StructureModifier() {
+		
+	}
+	
+	/**
+	 * Initialize using the same field types.
+	 * @param other - information to set.
+	 */
+	protected void initialize(StructureModifier<TField> other) {
+		initialize(other.targetType, other.fieldType, other.data, 
+				   other.defaultFields, other.converter, other.subtypeCache);
+	}
+	
+	/**
+	 * Initialize every field of this class.
+	 * @param targetType - type of the object we're reading and writing from.
+	 * @param fieldType - the common type of the fields we're modifying.
+	 * @param data - list of fields to modify.
+	 * @param defaultFields - list of fields that will be automatically initialized.
+	 * @param converter - converts between the common field type and the actual type the consumer expects.
+	 * @param subTypeCache - a structure modifier cache.
+	 */
+	protected void initialize(Class targetType, Class fieldType, 
+			  List<Field> data, Map<Field, Integer> defaultFields,
+			  EquivalentConverter<TField> converter, Map<Class, StructureModifier> subTypeCache) {
 		this.targetType = targetType;
 		this.fieldType = fieldType;
 		this.data = data;
+		this.defaultFields = defaultFields;
 		this.converter = converter;
 		this.subtypeCache = subTypeCache;
 	}
 	
-	private StructureModifier(StructureModifier<TField> other, Object target) {
-		this(other.targetType, other.fieldType, other.data, other.converter, other.subtypeCache);
-		this.target = target;
-	}
-	
 	/**
 	 * Reads the value of a field given its index.
 	 * @param fieldIndex - index of the field.
 	 * @return Value of the field.
-	 * @throws IllegalAccessException If we're unable to read the field due to a security limitation.
+	 * @throws FieldAccessException The field doesn't exist, or it cannot be accessed under the current security contraints.
 	 */
 	@SuppressWarnings("unchecked")
-	public TField read(int fieldIndex) throws IllegalAccessException {
+	public TField read(int fieldIndex) throws FieldAccessException {
 		if (fieldIndex < 0 || fieldIndex >= data.size())
-			throw new IllegalArgumentException("Field index must be within 0 - count");
+			throw new FieldAccessException("Field index must be within 0 - count", 
+					new IndexOutOfBoundsException("Out of bounds"));
 		if (target == null)
 			throw new IllegalStateException("Cannot read from a NULL target.");
 		
-		Object result = FieldUtils.readField(data.get(fieldIndex), target, true);
-		
-		// Use the converter, if we have it
-		if (converter != null)
-			return converter.getSpecific(result);
-		else
-			return (TField) result;
+		try {
+			Object result = FieldUtils.readField(data.get(fieldIndex), target, true);
+			
+			// Use the converter, if we have it
+			if (needConversion())
+				return converter.getSpecific(result);
+			else
+				return (TField) result;
+			
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot read field due to a security limitation.", e);
+		}
+	}
+
+	/**
+	 * Reads the value of a field if and ONLY IF it exists.
+	 * @param fieldIndex - index of the field.
+	 * @return Value of the field, or NULL if it doesn't exist.
+	 * @throws FieldAccessException The field cannot be accessed under the current security contraints.
+	 */
+	public TField readSafely(int fieldIndex) throws FieldAccessException {
+		if (fieldIndex >= 0 && fieldIndex < data.size()) {
+			return read(fieldIndex);
+		} else {
+			return null;
+		}
 	}
 	
 	/**
@@ -73,30 +157,58 @@ public class StructureModifier<TField> {
 	 * @param fieldIndex - index of the field.
 	 * @param value - new value of the field.
 	 * @return This structure modifier - for chaining.
-	 * @throws IllegalAccessException If we're unable to write to the field due to a security limitation.
+	 * @throws FieldAccessException The field doesn't exist, or it cannot be accessed under the current security contraints.
 	 */
-	public StructureModifier<TField> write(int fieldIndex, TField value) throws IllegalAccessException {
+	public StructureModifier<TField> write(int fieldIndex, TField value) throws FieldAccessException {
 		if (fieldIndex < 0 || fieldIndex >= data.size())
-			throw new IllegalArgumentException("Field index must be within 0 - count");
+			throw new FieldAccessException("Field index must be within 0 - count", 
+					new IndexOutOfBoundsException("Out of bounds"));
 		if (target == null)
 			throw new IllegalStateException("Cannot write to a NULL target.");
 		
 		// Use the converter, if it exists
-		Object obj = converter != null ? converter.getGeneric(value) : value;
-		FieldUtils.writeField(data.get(fieldIndex), target, obj, true);
+		Object obj = needConversion() ? converter.getGeneric(value) : value;
+		
+		try {
+			FieldUtils.writeField(data.get(fieldIndex), target, obj, true);
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot read field due to a security limitation.", e);
+		}
 		
 		// Make this method chainable
 		return this;
 	}
 	
+	/**
+	 * Whether or not we should use the converter instance.
+	 * @return TRUE if we should, FALSE otherwise.
+	 */
+	private final boolean needConversion() {
+		return converter != null && !customConvertHandling;
+	}
+	
+	/**
+	 * Writes the value of a given field IF and ONLY if it exists.
+	 * @param fieldIndex - index of the potential field.
+	 * @param value - new value of the field.
+	 * @return This structure modifer - for chaining.
+	 * @throws FieldAccessException The field cannot be accessed under the current security contraints.
+	 */
+	public StructureModifier<TField> writeSafely(int fieldIndex, TField value) throws FieldAccessException {
+		if (fieldIndex >= 0 && fieldIndex < data.size()) {
+			write(fieldIndex, value);
+		}
+		return this;
+	}
+	
 	/**
 	 * Correctly modifies the value of a field.
 	 * @param fieldIndex - index of the field to modify.
 	 * @param select - the function that modifies the field value.
 	 * @return This structure modifier - for chaining.
-	 * @throws IllegalAccessException
+	 * @throws FieldAccessException The field cannot be accessed under the current security contraints.
 	 */
-	public StructureModifier<TField> modify(int fieldIndex, Function<TField, TField> select) throws IllegalAccessException {
+	public StructureModifier<TField> modify(int fieldIndex, Function<TField, TField> select) throws FieldAccessException {
 		TField value = read(fieldIndex);
 		return write(fieldIndex, select.apply(value));
 	}
@@ -110,6 +222,28 @@ public class StructureModifier<TField> {
 		return withType(fieldType, null);
 	}
 	
+	/**
+	 * Sets all non-primitive fields to a more fitting default value. See {@link DefaultInstances#getDefault(Class)}.
+	 * @return The current structure modifier - for chaining.
+	 * @throws FieldAccessException If we're unable to write to the fields due to a security limitation.
+	 */
+	public StructureModifier<TField> writeDefaults() throws FieldAccessException {
+		
+		DefaultInstances generator = DefaultInstances.DEFAULT;
+		
+		// Write a default instance to every field
+		for (Field field : defaultFields.keySet()) {
+			try {
+				FieldUtils.writeField(field, target, 
+						generator.getDefault(field.getType()), true);
+			} catch (IllegalAccessException e) {
+				throw new FieldAccessException("Cannot write to field due to a security limitation.", e);
+			}
+		}
+		
+		return this;
+	}
+	
 	/**
 	 * Retrieves a structure modifier that only reads and writes fields of a given type.
 	 * @param fieldType - the type, or supertype, of every field to modify.
@@ -121,28 +255,56 @@ public class StructureModifier<TField> {
 		
 		StructureModifier<T> result = subtypeCache.get(fieldType);
 		
-		if (fieldType.equals(this.fieldType)) {
-			
-			// We're dealing with the exact field type.
-			return withConverter(converter);
-			
-		} else if (result == null) {
+		// Do we need to update the cache?
+		if (result == null) {
 			List<Field> filtered = new ArrayList<Field>();
+			Map<Field, Integer> defaults = new HashMap<Field, Integer>();
+			int index = 0;
 			
 			for (Field field : data) {
-				if (fieldType.isAssignableFrom(field.getType())) {
+				if (fieldType != null && fieldType.isAssignableFrom(field.getType())) {
 					filtered.add(field);
+					
+					// Don't use the original index
+					if (defaultFields.containsKey(field))
+						defaults.put(field, index);
 				}
+				
+				// Keep track of the field index
+				index++;
 			}
 			
 			// Cache structure modifiers
-			result = new StructureModifier<T>(targetType, fieldType, filtered, 
-											  converter, new HashMap<Class, StructureModifier>());
-			subtypeCache.put(fieldType, result);
+			result = withFieldType(fieldType, filtered, defaults, converter);
+			
+			if (fieldType != null) {
+				subtypeCache.put(fieldType, result);
+				
+				// Automatically compile the structure modifier
+				if (BackgroundCompiler.getInstance() != null) 
+					BackgroundCompiler.getInstance().scheduleCompilation(subtypeCache, fieldType);
+			}
 		}
 		
 		// Add the target too
-		return result.withTarget(target);
+		result = result.withTarget(target);
+		
+		// And the converter, if it's needed
+		if (!sameConverter(result.converter, converter)) {
+			result = result.withConverter(converter);
+		}
+		
+		return result;
+	}
+	
+	private boolean sameConverter(EquivalentConverter<?> a, EquivalentConverter<?> b) {
+		// Compare the converter types
+		if (a == null)
+			return b == null;
+		else if (b == null)
+			return a == null;
+		else
+			return a.getSpecificType().equals(b.getSpecificType());
 	}
 	
 	/**
@@ -177,30 +339,110 @@ public class StructureModifier<TField> {
 		return data.size();
 	}
 	
+	/**
+	 * Create a new structure modifier for the new field type.
+	 * @param fieldType - common type of each field.
+	 * @param filtered - list of fields after filtering the original modifier.
+	 * @param defaults - list of default values after filtering the original.
+	 * @param converter - the new converter.
+	 * @return A new structure modifier.
+	 */
+	protected <T> StructureModifier<T> withFieldType(
+			Class fieldType, List<Field> filtered, 
+			Map<Field, Integer> defaults, EquivalentConverter<T> converter) {
+		
+		StructureModifier<T> result = new StructureModifier<T>();
+		result.initialize(targetType, fieldType, filtered, defaults, 
+						  converter, new ConcurrentHashMap<Class, StructureModifier>());
+		return result;
+	}
+	
 	/**
 	 * Retrieves a structure modifier of the same type for a different object target.
 	 * @param target - different target of the same type.
 	 * @return Structure modifier with the new target.
 	 */
 	public StructureModifier<TField> withTarget(Object target) {
-		return new StructureModifier<TField>(this, target);
+		StructureModifier<TField> copy = new StructureModifier<TField>();
+		
+		// Create a new instance
+		copy.initialize(targetType, fieldType, data, defaultFields, converter, subtypeCache);
+		copy.target = target;
+		return copy;
 	}
 	
 	/**
 	 * Retrieves a structure modifier with the same type and target, but using a new object converter.
-	 * @param converter- the object converter to use.
+	 * @param converter - the object converter to use.
 	 * @return Structure modifier with the new converter.
 	 */
 	@SuppressWarnings("unchecked")
 	private <T> StructureModifier<T> withConverter(EquivalentConverter<T> converter) {
-		StructureModifier copy = new StructureModifier(this, target);
+		StructureModifier copy = withTarget(target);
 		
-		copy.converter = converter;
+		copy.setConverter(converter);
 		return copy;
 	}
 	
+	/**
+	 * Set the current object converter. Should only be called during construction.
+	 * @param converter - current object converter.
+	 */
+	protected void setConverter(EquivalentConverter<TField> converter) {
+		this.converter = converter;
+	}
+	
+	/**
+	 * Retrieves a list of the fields matching the constraints of this structure modifier.
+	 * @return List of fields.
+	 */
+	public List<Field> getFields() {
+		return ImmutableList.copyOf(data);
+	}
+
+	/**
+	 * Retrieve every value stored in the fields of the current type.
+	 * @return Every field value.
+	 * @throws FieldAccessException Unable to access one or all of the fields
+	 */
+	public List<TField> getValues() throws FieldAccessException {
+		List<TField> values = new ArrayList<TField>();
+		
+		for (int i = 0; i < size(); i++) {
+			values.add(read(i));
+		}
+		
+		return values;
+	}
+	
+	// Used to generate plausible default values
+	private static Map<Field, Integer> generateDefaultFields(List<Field> fields) {
+		
+		Map<Field, Integer> requireDefaults = new HashMap<Field, Integer>();
+		DefaultInstances generator = DefaultInstances.DEFAULT;
+		int index = 0;
+		
+		for (Field field : fields) {
+			Class<?> type = field.getType();
+			
+			// First, ignore primitive fields
+			if (!PrimitiveUtils.isPrimitive(type)) {
+				// Next, see if we actually can generate a default value
+				if (generator.getDefault(type) != null) {
+					// If so, require it
+					requireDefaults.put(field, index);
+				}
+			}
+			
+			// Increment field index
+			index++;
+		}
+		
+		return requireDefaults;
+	}
+	
 	// Used to filter out irrelevant fields
-	private static List<Field> getFields(Class type) {
+	private static List<Field> getFields(Class type, Class superclassExclude) {
 		List<Field> result = new ArrayList<Field>();
 		
 		// Retrieve every private and public field
@@ -208,7 +450,10 @@ public class StructureModifier<TField> {
 			int mod = field.getModifiers();
 			
 			// Ignore static, final and "abstract packet" fields
-			if (!Modifier.isFinal(mod) && !Modifier.isStatic(mod) && !field.getDeclaringClass().equals(Packet.class)) {
+			if (!Modifier.isFinal(mod) && !Modifier.isStatic(mod) && (
+					superclassExclude == null || !field.getDeclaringClass().equals(superclassExclude)
+				)) {
+				
 				result.add(field);
 			}
 		}

ProtocolLib/src/com/comphenix/protocol/reflect/VolatileField.java

@@ -1,8 +1,24 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
 package com.comphenix.protocol.reflect;
 
 import java.lang.reflect.Field;
 
-
 /**
  * Represents a field that will revert to its original state when this class is garbaged collected.
  * 
@@ -139,6 +155,13 @@ public class VolatileField {
 		}
 	}
 	
+	/**
+	 * Determine whether or not we'll need to revert the value.
+	 */
+	public boolean isCurrentSet() {
+		return currentSet;
+	}
+	
 	private void ensureLoaded() {
 		// Load the value if we haven't already
 		if (!previousLoaded) {

ProtocolLib/src/com/comphenix/protocol/reflect/compiler/BackgroundCompiler.java

@@ -0,0 +1,183 @@
+package com.comphenix.protocol.reflect.compiler;
+
+import java.util.Map;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import com.comphenix.protocol.reflect.StructureModifier;
+
+/**
+ * Compiles structure modifiers on a background thread.
+ * <p>
+ * This is necessary as we cannot block the main thread.
+ * 
+ * @author Kristian
+ */
+public class BackgroundCompiler {
+
+	// How long to wait for a shutdown
+	public static final int SHUTDOWN_DELAY_MS = 2000;
+	
+	// The single background compiler we're using
+	private static BackgroundCompiler backgroundCompiler;
+	
+	private StructureCompiler compiler;
+	private boolean enabled;
+	private boolean shuttingDown;
+	
+	private ExecutorService executor;
+	
+	/**
+	 * Retrieves the current background compiler.
+	 * @return Current background compiler.
+	 */
+	public static BackgroundCompiler getInstance() {
+		return backgroundCompiler;
+	}
+	
+	/**
+	 * Sets the single background compiler we're using.
+	 * @param backgroundCompiler - current background compiler, or NULL if the library is not loaded.
+	 */
+	public static void setInstance(BackgroundCompiler backgroundCompiler) {
+		BackgroundCompiler.backgroundCompiler = backgroundCompiler;
+	}
+	
+	/**
+	 * Initialize a background compiler.
+	 * @param loader - class loader from Bukkit.
+	 */
+	public BackgroundCompiler(ClassLoader loader) {
+		this(loader, Executors.newSingleThreadExecutor());
+	}
+
+	/**
+	 * Initialize a background compiler utilizing the given thread pool.
+	 * @param loader - class loader from Bukkit.
+	 * @param executor - thread pool we'll use.
+	 */
+	public BackgroundCompiler(ClassLoader loader, ExecutorService executor) {
+		if (loader == null)
+			throw new IllegalArgumentException("loader cannot be NULL");
+		if (executor == null)
+			throw new IllegalArgumentException("executor cannot be NULL");
+		
+		this.compiler = new StructureCompiler(loader);
+		this.executor = executor;
+		this.enabled = true;
+	}
+	
+	/**
+	 * Ensure that the indirectly given structure modifier is eventually compiled.
+	 * @param cache - store of structure modifiers.
+	 * @param key - key of the structure modifier to compile.
+	 */
+	@SuppressWarnings("rawtypes")
+	public void scheduleCompilation(final Map<Class, StructureModifier> cache, final Class key) {
+		
+		@SuppressWarnings("unchecked")
+		final StructureModifier<Object> uncompiled = cache.get(key);
+		
+		if (uncompiled != null) {
+			scheduleCompilation(uncompiled, new CompileListener<Object>() {
+				@Override
+				public void onCompiled(StructureModifier<Object> compiledModifier) {
+					// Update cache
+					cache.put(key, compiledModifier);
+				}
+			});
+		}
+	}
+	
+	/**
+	 * Ensure that the given structure modifier is eventually compiled.
+	 * @param uncompiled - structure modifier to compile.
+	 * @param listener - listener responsible for responding to the compilation.
+	 */
+	public <TKey> void scheduleCompilation(final StructureModifier<TKey> uncompiled, final CompileListener<TKey> listener) {
+
+		// Only schedule if we're enabled
+		if (enabled && !shuttingDown) {
+			
+			// Don't try to schedule anything
+			if (executor == null || executor.isShutdown())
+				return;
+			
+			try {
+				executor.submit(new Callable<Object>() {
+					@Override
+					public Object call() throws Exception {
+		
+						StructureModifier<TKey> modifier = uncompiled;
+						
+						// Do our compilation
+						modifier = compiler.compile(modifier);
+						listener.onCompiled(modifier);
+						
+						// We'll also return the new structure modifier
+						return modifier;
+					}
+				});
+			} catch (RejectedExecutionException e) {
+				// Occures when the underlying queue is overflowing. Since the compilation  
+				// is only an optmization and not really essential we'll just log this failure 
+				// and move on.
+				Logger.getLogger("Minecraft").log(Level.WARNING, "Unable to schedule compilation task.", e);
+			}
+		}
+	}
+	
+	/**
+	 * Clean up after ourselves using the default timeout.
+	 */
+	public void shutdownAll() {
+		shutdownAll(SHUTDOWN_DELAY_MS, TimeUnit.MILLISECONDS);
+	}
+	
+	/**
+	 * Clean up after ourselves.
+	 * @param timeout - the maximum time to wait.
+	 * @param unit - the time unit of the timeout argument.
+	 */
+	public void shutdownAll(long timeout, TimeUnit unit) {
+		setEnabled(false);
+		shuttingDown = true;
+		executor.shutdown();
+		
+		try {
+			executor.awaitTermination(timeout, unit);
+		} catch (InterruptedException e) {
+			// Unlikely to ever occur.
+			e.printStackTrace();
+		}
+	}
+	
+	/**
+	 * Retrieve whether or not the background compiler is enabled.
+	 * @return TRUE if it is enabled, FALSE otherwise.
+	 */
+	public boolean isEnabled() {
+		return enabled;
+	}
+
+	/**
+	 * Sets whether or not the background compiler is enabled.
+	 * @param enabled - TRUE to enable it, FALSE otherwise.
+	 */
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
+	/**
+	 * Retrieve the current structure compiler.
+	 * @return Current structure compiler.
+	 */
+	public StructureCompiler getCompiler() {
+		return compiler;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/compiler/BoxingHelper.java

@@ -0,0 +1,275 @@
+package com.comphenix.protocol.reflect.compiler;
+
+import net.sf.cglib.asm.*;
+
+/**
+ * Used by the compiler to automatically box and unbox values.
+ */
+class BoxingHelper {
+
+	private final static Type BYTE_TYPE = Type.getObjectType("java/lang/Byte");
+	private final static Type BOOLEAN_TYPE = Type.getObjectType("java/lang/Boolean");
+	private final static Type SHORT_TYPE = Type.getObjectType("java/lang/Short");
+	private final static Type CHARACTER_TYPE = Type.getObjectType("java/lang/Character");
+	private final static Type INTEGER_TYPE = Type.getObjectType("java/lang/Integer");
+	private final static Type FLOAT_TYPE = Type.getObjectType("java/lang/Float");
+	private final static Type LONG_TYPE = Type.getObjectType("java/lang/Long");
+	private final static Type DOUBLE_TYPE = Type.getObjectType("java/lang/Double");
+	private final static Type NUMBER_TYPE = Type.getObjectType("java/lang/Number");
+	private final static Type OBJECT_TYPE = Type.getObjectType("java/lang/Object");
+
+	private final static MethodDescriptor BOOLEAN_VALUE = MethodDescriptor.getMethod("boolean booleanValue()");
+	private final static MethodDescriptor CHAR_VALUE = MethodDescriptor.getMethod("char charValue()");
+	private final static MethodDescriptor INT_VALUE = MethodDescriptor.getMethod("int intValue()");
+	private final static MethodDescriptor FLOAT_VALUE = MethodDescriptor.getMethod("float floatValue()");
+	private final static MethodDescriptor LONG_VALUE = MethodDescriptor.getMethod("long longValue()");
+	private final static MethodDescriptor DOUBLE_VALUE = MethodDescriptor.getMethod("double doubleValue()");
+
+	private MethodVisitor mv;
+	
+	public BoxingHelper(MethodVisitor mv) {
+		this.mv = mv;
+	}
+	
+	/**
+	 * Generates the instructions to box the top stack value. This value is
+	 * replaced by its boxed equivalent on top of the stack.
+	 *
+	 * @param type the type of the top stack value.
+	 */
+	public void box(final Type type){
+		if(type.getSort() == Type.OBJECT || type.getSort() == Type.ARRAY) {
+			return;
+		}
+		
+		if(type == Type.VOID_TYPE) {
+			push((String) null);
+		} else {
+			Type boxed = type;
+			
+			switch(type.getSort()) {
+				case Type.BYTE:
+					boxed = BYTE_TYPE;
+					break;
+				case Type.BOOLEAN:
+					boxed = BOOLEAN_TYPE;
+					break;
+				case Type.SHORT:
+					boxed = SHORT_TYPE;
+					break;
+				case Type.CHAR:
+					boxed = CHARACTER_TYPE;
+					break;
+				case Type.INT:
+					boxed = INTEGER_TYPE;
+					break;
+				case Type.FLOAT:
+					boxed = FLOAT_TYPE;
+					break;
+				case Type.LONG:
+					boxed = LONG_TYPE;
+					break;
+				case Type.DOUBLE:
+					boxed = DOUBLE_TYPE;
+					break;
+			}
+			
+			newInstance(boxed);
+			if(type.getSize() == 2) {
+				// Pp -> Ppo -> oPpo -> ooPpo -> ooPp -> o
+				dupX2();
+				dupX2();
+				pop();
+			} else {
+				// p -> po -> opo -> oop -> o
+				dupX1();
+				swap();
+			}
+			
+			invokeConstructor(boxed, new MethodDescriptor("<init>", Type.VOID_TYPE, new Type[] {type}));
+		}
+	}
+	
+	/**
+	 * Generates the instruction to invoke a constructor.
+	 *
+	 * @param type   the class in which the constructor is defined.
+	 * @param method the constructor to be invoked.
+	 */
+	public void invokeConstructor(final Type type, final MethodDescriptor method){
+		invokeInsn(Opcodes.INVOKESPECIAL, type, method);
+	}
+	
+	/**
+	 * Generates a DUP_X1 instruction.
+	 */
+	public void dupX1(){
+		mv.visitInsn(Opcodes.DUP_X1);
+	}
+
+	/**
+	 * Generates a DUP_X2 instruction.
+	 */
+	public void dupX2(){
+		mv.visitInsn(Opcodes.DUP_X2);
+	}
+	
+	/**
+	 * Generates a POP instruction.
+	 */
+	public void pop(){
+		mv.visitInsn(Opcodes.POP);
+	}
+
+	/**
+	 * Generates a SWAP instruction.
+	 */
+	public void swap(){
+		mv.visitInsn(Opcodes.SWAP);
+	}
+	
+	/**
+	 * Generates the instruction to push the given value on the stack.
+	 *
+	 * @param value the value to be pushed on the stack.
+	 */
+	public void push(final boolean value){
+		push(value ? 1 : 0);
+	}
+	
+	/**
+	 * Generates the instruction to push the given value on the stack.
+	 * 
+	 * @param value the value to be pushed on the stack.
+	 */
+	public void push(final int value) {
+		if (value >= -1 && value <= 5) {
+			mv.visitInsn(Opcodes.ICONST_0 + value);
+		} else if (value >= Byte.MIN_VALUE && value <= Byte.MAX_VALUE) {
+			mv.visitIntInsn(Opcodes.BIPUSH, value);
+		} else if (value >= Short.MIN_VALUE && value <= Short.MAX_VALUE) {
+			mv.visitIntInsn(Opcodes.SIPUSH, value);
+		} else {
+			mv.visitLdcInsn(new Integer(value));
+		}
+	}
+
+	/**
+	 * Generates the instruction to create a new object.
+	 *
+	 * @param type the class of the object to be created.
+	 */
+	public void newInstance(final Type type){
+		typeInsn(Opcodes.NEW, type);
+	}
+	
+	/**
+	 * Generates the instruction to push the given value on the stack.
+	 * 
+	 * @param value the value to be pushed on the stack. May be <tt>null</tt>.
+	 */
+	public void push(final String value) {
+		if (value == null) {
+			mv.visitInsn(Opcodes.ACONST_NULL);
+		} else {
+			mv.visitLdcInsn(value);
+		}
+	}
+
+	/**
+	 * Generates the instructions to unbox the top stack value. This value is
+	 * replaced by its unboxed equivalent on top of the stack.
+	 * 
+	 * @param type
+	 *            the type of the top stack value.
+	 */
+	public void unbox(final Type type){
+		Type t = NUMBER_TYPE;
+		MethodDescriptor sig = null;
+		
+		switch(type.getSort()) {
+			case Type.VOID:
+				return;
+			case Type.CHAR:
+				t = CHARACTER_TYPE;
+				sig = CHAR_VALUE;
+				break;
+			case Type.BOOLEAN:
+				t = BOOLEAN_TYPE;
+				sig = BOOLEAN_VALUE;
+				break;
+			case Type.DOUBLE:
+				sig = DOUBLE_VALUE;
+				break;
+			case Type.FLOAT:
+				sig = FLOAT_VALUE;
+				break;
+			case Type.LONG:
+				sig = LONG_VALUE;
+				break;
+			case Type.INT:
+			case Type.SHORT:
+			case Type.BYTE:
+				sig = INT_VALUE;
+			}
+		
+		if(sig == null) {
+			checkCast(type);
+		} else {
+			checkCast(t);
+			invokeVirtual(t, sig);
+		}
+	}
+
+	/**
+	 * Generates the instruction to check that the top stack value is of the
+	 * given type.
+	 *
+	 * @param type a class or interface type.
+	 */
+	public void checkCast(final Type type){
+		if(!type.equals(OBJECT_TYPE)) {
+			typeInsn(Opcodes.CHECKCAST, type);
+		}
+	}
+	
+	/**
+	 * Generates the instruction to invoke a normal method.
+	 *
+	 * @param owner  the class in which the method is defined.
+	 * @param method the method to be invoked.
+	 */
+	public void invokeVirtual(final Type owner, final MethodDescriptor method){
+		invokeInsn(Opcodes.INVOKEVIRTUAL, owner, method);
+	}
+	
+	/**
+	 * Generates an invoke method instruction.
+	 *
+	 * @param opcode the instruction's opcode.
+	 * @param type   the class in which the method is defined.
+	 * @param method the method to be invoked.
+	 */
+	private void invokeInsn(final int opcode, final Type type, final MethodDescriptor method){
+		String owner = type.getSort() == Type.ARRAY ? type.getDescriptor() : type.getInternalName();
+		mv.visitMethodInsn(opcode, owner, method.getName(), method.getDescriptor());
+	}
+	
+	/**
+	 * Generates a type dependent instruction.
+	 *
+	 * @param opcode the instruction's opcode.
+	 * @param type   the instruction's operand.
+	 */
+	private void typeInsn(final int opcode, final Type type){
+		String desc;
+		
+		if(type.getSort() == Type.ARRAY) {
+			desc = type.getDescriptor();
+		} else { 
+			desc = type.getInternalName();
+		}
+		
+		mv.visitTypeInsn(opcode, desc);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/compiler/CompileListener.java

@@ -0,0 +1,17 @@
+package com.comphenix.protocol.reflect.compiler;
+
+import com.comphenix.protocol.reflect.StructureModifier;
+
+/**
+ * Used to save the result of an compilation.
+ * 
+ * @author Kristian
+ * @param <TKey> - type of the structure modifier field.
+ */
+public interface CompileListener<TKey> {
+	/**
+	 * Invoked when a structure modifier has been successfully compiled.
+	 * @param compiledModifier - the compiled structure modifier.
+	 */
+	public void onCompiled(StructureModifier<TKey> compiledModifier);
+}

ProtocolLib/src/com/comphenix/protocol/reflect/compiler/CompiledStructureModifier.java

@@ -0,0 +1,73 @@
+package com.comphenix.protocol.reflect.compiler;
+
+import java.lang.reflect.Field;
+import java.util.Map;
+
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.StructureModifier;
+import com.comphenix.protocol.reflect.instances.DefaultInstances;
+
+/**
+ * Represents a compiled structure modifier.
+ * 
+ * @author Kristian
+ * @param <TField> Field type.
+ */
+public abstract class CompiledStructureModifier<TField> extends StructureModifier<TField> {
+	// Used to compile instances of structure modifiers
+	protected StructureCompiler compiler;
+	
+	public CompiledStructureModifier() {
+		super();
+		customConvertHandling = true;
+	}
+	
+	// Speed up the default writer
+	@SuppressWarnings("unchecked")
+	@Override
+	public StructureModifier<TField> writeDefaults() throws FieldAccessException {
+		
+		DefaultInstances generator = DefaultInstances.DEFAULT;
+		
+		// Write a default instance to every field
+		for (Map.Entry<Field, Integer> entry  : defaultFields.entrySet()) {
+			Integer index = entry.getValue();
+			Field field = entry.getKey();
+			
+			write(index, (TField) generator.getDefault(field.getType()));
+		}
+		
+		return this;
+	}
+	
+	@SuppressWarnings("unchecked")
+	@Override
+	public final TField read(int fieldIndex) throws FieldAccessException {
+		Object result = readGenerated(fieldIndex);
+		
+		if (converter != null)
+			return converter.getSpecific(result);
+		else
+			return (TField) result;
+	}
+	
+	protected abstract Object readGenerated(int fieldIndex) throws FieldAccessException;
+
+	@SuppressWarnings("unchecked")
+	@Override
+	public StructureModifier<TField> write(int index, Object value) throws FieldAccessException {
+		if (converter != null)
+			value = converter.getGeneric((TField) value);
+		return writeGenerated(index, value);
+	}
+	
+	protected abstract StructureModifier<TField> writeGenerated(int index, Object value) throws FieldAccessException;
+	
+	@Override
+	public StructureModifier<TField> withTarget(Object target) {
+		if (compiler != null)
+			return compiler.compile(super.withTarget(target));
+		else
+			return super.withTarget(target);
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/compiler/MethodDescriptor.java

@@ -0,0 +1,220 @@
+package com.comphenix.protocol.reflect.compiler;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import net.sf.cglib.asm.Type;
+
+/**
+ * Represents a method.
+ */
+class MethodDescriptor {
+
+    /**
+     * The method name.
+     */
+    private final String name;
+
+    /**
+     * The method descriptor.
+     */
+    private final String desc;
+
+    /**
+     * Maps primitive Java type names to their descriptors.
+     */
+    private static final Map<String, String> DESCRIPTORS;
+
+    static {
+        DESCRIPTORS = new HashMap<String, String>();
+        DESCRIPTORS.put("void", "V");
+        DESCRIPTORS.put("byte", "B");
+        DESCRIPTORS.put("char", "C");
+        DESCRIPTORS.put("double", "D");
+        DESCRIPTORS.put("float", "F");
+        DESCRIPTORS.put("int", "I");
+        DESCRIPTORS.put("long", "J");
+        DESCRIPTORS.put("short", "S");
+        DESCRIPTORS.put("boolean", "Z");
+    }
+
+    /**
+     * Creates a new {@link Method}.
+     * 
+     * @param name the method's name.
+     * @param desc the method's descriptor.
+     */
+    public MethodDescriptor(final String name, final String desc) {
+        this.name = name;
+        this.desc = desc;
+    }
+
+    /**
+     * Creates a new {@link Method}.
+     * 
+     * @param name the method's name.
+     * @param returnType the method's return type.
+     * @param argumentTypes the method's argument types.
+     */
+    public MethodDescriptor(
+        final String name,
+        final Type returnType,
+        final Type[] argumentTypes)
+    {
+        this(name, Type.getMethodDescriptor(returnType, argumentTypes));
+    }
+
+    /**
+     * Returns a {@link Method} corresponding to the given Java method
+     * declaration.
+     * 
+     * @param method a Java method declaration, without argument names, of the
+     *        form "returnType name (argumentType1, ... argumentTypeN)", where
+     *        the types are in plain Java (e.g. "int", "float",
+     *        "java.util.List", ...). Classes of the java.lang package can be
+     *        specified by their unqualified name; all other classes names must
+     *        be fully qualified.
+     * @return a {@link Method} corresponding to the given Java method
+     *         declaration.
+     * @throws IllegalArgumentException if <code>method</code> could not get
+     *         parsed.
+     */
+    public static MethodDescriptor getMethod(final String method)
+            throws IllegalArgumentException
+    {
+        return getMethod(method, false);
+    }
+
+    /**
+     * Returns a {@link Method} corresponding to the given Java method
+     * declaration.
+     * 
+     * @param method a Java method declaration, without argument names, of the
+     *        form "returnType name (argumentType1, ... argumentTypeN)", where
+     *        the types are in plain Java (e.g. "int", "float",
+     *        "java.util.List", ...). Classes of the java.lang package may be
+     *        specified by their unqualified name, depending on the
+     *        defaultPackage argument; all other classes names must be fully
+     *        qualified.
+     * @param defaultPackage true if unqualified class names belong to the
+     *        default package, or false if they correspond to java.lang classes.
+     *        For instance "Object" means "Object" if this option is true, or
+     *        "java.lang.Object" otherwise.
+     * @return a {@link Method} corresponding to the given Java method
+     *         declaration.
+     * @throws IllegalArgumentException if <code>method</code> could not get
+     *         parsed.
+     */
+    public static MethodDescriptor getMethod(
+        final String method,
+        final boolean defaultPackage) throws IllegalArgumentException
+    {
+        int space = method.indexOf(' ');
+        int start = method.indexOf('(', space) + 1;
+        int end = method.indexOf(')', start);
+        if (space == -1 || start == -1 || end == -1) {
+            throw new IllegalArgumentException();
+        }
+        String returnType = method.substring(0, space);
+        String methodName = method.substring(space + 1, start - 1).trim();
+        StringBuffer sb = new StringBuffer();
+        sb.append('(');
+        int p;
+        do {
+            String s;
+            p = method.indexOf(',', start);
+            if (p == -1) {
+                s = map(method.substring(start, end).trim(), defaultPackage);
+            } else {
+                s = map(method.substring(start, p).trim(), defaultPackage);
+                start = p + 1;
+            }
+            sb.append(s);
+        } while (p != -1);
+        sb.append(')');
+        sb.append(map(returnType, defaultPackage));
+        return new MethodDescriptor(methodName, sb.toString());
+    }
+
+    private static String map(final String type, final boolean defaultPackage) {
+        if ("".equals(type)) {
+            return type;
+        }
+
+        StringBuffer sb = new StringBuffer();
+        int index = 0;
+        while ((index = type.indexOf("[]", index) + 1) > 0) {
+            sb.append('[');
+        }
+
+        String t = type.substring(0, type.length() - sb.length() * 2);
+        String desc = (String) DESCRIPTORS.get(t);
+        if (desc != null) {
+            sb.append(desc);
+        } else {
+            sb.append('L');
+            if (t.indexOf('.') < 0) {
+                if (!defaultPackage) {
+                    sb.append("java/lang/");
+                }
+                sb.append(t);
+            } else {
+                sb.append(t.replace('.', '/'));
+            }
+            sb.append(';');
+        }
+        return sb.toString();
+    }
+
+    /**
+     * Returns the name of the method described by this object.
+     * 
+     * @return the name of the method described by this object.
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Returns the descriptor of the method described by this object.
+     * 
+     * @return the descriptor of the method described by this object.
+     */
+    public String getDescriptor() {
+        return desc;
+    }
+
+    /**
+     * Returns the return type of the method described by this object.
+     * 
+     * @return the return type of the method described by this object.
+     */
+    public Type getReturnType() {
+        return Type.getReturnType(desc);
+    }
+
+    /**
+     * Returns the argument types of the method described by this object.
+     * 
+     * @return the argument types of the method described by this object.
+     */
+    public Type[] getArgumentTypes() {
+        return Type.getArgumentTypes(desc);
+    }
+
+    public String toString() {
+        return name + desc;
+    }
+
+    public boolean equals(final Object o) {
+        if (!(o instanceof MethodDescriptor)) {
+            return false;
+        }
+        MethodDescriptor other = (MethodDescriptor) o;
+        return name.equals(other.name) && desc.equals(other.desc);
+    }
+
+    public int hashCode() {
+        return name.hashCode() ^ desc.hashCode();
+    }
+}

ProtocolLib/src/com/comphenix/protocol/reflect/compiler/StructureCompiler.java

@@ -0,0 +1,443 @@
+package com.comphenix.protocol.reflect.compiler;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.comphenix.protocol.reflect.PrimitiveUtils;
+import com.comphenix.protocol.reflect.StructureModifier;
+import com.google.common.base.Objects;
+
+import net.sf.cglib.asm.*;
+
+// public class CompiledStructureModifierPacket20<TField> extends CompiledStructureModifier<TField> {
+//	
+//		private Packet20NamedEntitySpawn typedTarget;
+//	
+//		public CompiledStructureModifierPacket20(StructureModifier<TField> other, StructureCompiler compiler) {
+//			super();
+//			initialize(other);
+//			this.target = other.getTarget();
+//			this.typedTarget = (Packet20NamedEntitySpawn) target;
+//			this.compiler = compiler;
+//		}
+//	
+//		@Override
+//		protected Object readGenerated(int fieldIndex) throws FieldAccessException {
+//	
+//			Packet20NamedEntitySpawn target = typedTarget;
+//			
+//			switch (fieldIndex) {
+//			case 0: return (Object) target.a;
+//			case 1: return (Object) target.b;
+//			case 2: return (Object) target.c;
+//			case 3: return super.read(fieldIndex);
+//			case 4: return super.read(fieldIndex);
+//			case 5: return (Object) target.f;
+//			case 6: return (Object) target.g;
+//			case 7: return (Object) target.h;
+//			default:
+//				throw new FieldAccessException("Invalid index " + fieldIndex);
+//			}
+//		}
+//	
+//		@Override
+//		protected StructureModifier<TField> writeGenerated(int index, Object value) throws FieldAccessException {
+//			
+//			Packet20NamedEntitySpawn target = typedTarget;
+//			
+//			switch (index) {
+//			case 0: target.a = (Integer) value; break;
+//			case 1: target.b = (String) value; break;
+//			case 2: target.c = (Integer) value; break;
+//			case 3: target.d = (Integer) value; break;
+//			case 4: super.write(index, value); break;
+//			case 5: super.write(index, value); break;
+//			case 6: target.g = (Byte) value; break;
+//			case 7: target.h = (Integer) value; break;
+//			default:
+//				throw new FieldAccessException("Invalid index " + index);
+//			}
+//			
+//			// Chaining
+//			return this;
+//		}
+//	}
+
+/**
+ * Represents a StructureModifier compiler.
+ * 
+ * @author Kristian
+ */
+public final class StructureCompiler {
+
+	// Used to store generated classes of different types
+	@SuppressWarnings("rawtypes")
+	private class StructureKey {
+		private Class targetType;
+		private Class fieldType;
+		
+		public StructureKey(Class targetType, Class fieldType) {
+			this.targetType = targetType;
+			this.fieldType = fieldType;
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hashCode(targetType, fieldType);
+		}
+		
+		@Override
+		public boolean equals(Object obj) {
+			if (obj instanceof StructureKey) {
+				StructureKey other = (StructureKey) obj;
+				return Objects.equal(targetType, other.targetType) &&
+					   Objects.equal(fieldType, other.fieldType);
+			}
+			return false;
+		}
+	}
+	
+	// Used to load classes
+	private volatile static Method defineMethod;
+	
+	@SuppressWarnings("rawtypes")
+	private Map<StructureKey, Class> compiledCache = new HashMap<StructureKey, Class>();
+	
+	// The class loader we'll store our classes
+	private ClassLoader loader;
+	
+	// References to other classes
+	private static String PACKAGE_NAME = "com/comphenix/protocol/reflect/compiler";
+	private static String SUPER_CLASS = "com/comphenix/protocol/reflect/StructureModifier";
+	private static String COMPILED_CLASS = PACKAGE_NAME + "/CompiledStructureModifier";
+	private static String FIELD_EXCEPTION_CLASS = "com/comphenix/protocol/reflect/FieldAccessException";
+	
+	/**
+	 * Construct a structure compiler.
+	 * @param loader - main class loader.
+	 */
+	StructureCompiler(ClassLoader loader) {
+		this.loader = loader;
+	}
+	
+	/**
+	 * Compiles the given structure modifier.
+	 * <p>
+	 * WARNING: Do NOT call this method in the main thread. Compiling may easily take 10 ms, which is already 
+	 * over 1/4 of a tick (50 ms). Let the background thread automatically compile the structure modifiers instead.
+	 * @param source - structure modifier to compile.
+	 * @return A compiled structure modifier.
+	 */
+	@SuppressWarnings("unchecked")
+	public synchronized <TField> StructureModifier<TField> compile(StructureModifier<TField> source) {
+
+		// We cannot optimize a structure modifier with no public fields
+		if (!isAnyPublic(source.getFields())) {
+			return source;
+		}
+		
+		StructureKey key = new StructureKey(source.getTargetType(), source.getFieldType());
+		Class<?> compiledClass = compiledCache.get(key);
+		
+		if (!compiledCache.containsKey(key)) {
+			compiledClass = generateClass(source);
+			compiledCache.put(key, compiledClass);
+		}
+		
+		// Next, create an instance of this class
+		try {
+			return (StructureModifier<TField>) compiledClass.getConstructor(
+					StructureModifier.class, StructureCompiler.class).
+					 newInstance(source, this);
+		} catch (IllegalArgumentException e) {
+			throw new IllegalStateException("Used invalid parameters in instance creation", e);
+		} catch (SecurityException e) {
+			throw new RuntimeException("Security limitation!", e);
+		} catch (InstantiationException e) {
+			throw new RuntimeException("Error occured while instancing generated class.", e);
+		} catch (IllegalAccessException e) {
+			throw new RuntimeException("Security limitation! Cannot create instance of dynamic class.", e);
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException("Error occured while instancing generated class.", e);
+		} catch (NoSuchMethodException e) {
+			throw new IllegalStateException("Cannot happen.", e);
+		}
+	}
+	
+	private <TField> Class<?> generateClass(StructureModifier<TField> source) {
+		
+		ClassWriter cw = new ClassWriter(0);
+
+		@SuppressWarnings("rawtypes")
+		Class targetType = source.getTargetType();
+		
+		String className = "CompiledStructure$" + targetType.getSimpleName() + source.getFieldType().getSimpleName();
+		String targetSignature = Type.getDescriptor(targetType);
+		String targetName = targetType.getName().replace('.', '/');
+		
+		try {
+			// This class might have been generated before. Try to load it.
+			Class<?> before = loader.loadClass(PACKAGE_NAME.replace('/', '.') + "." + className);
+			
+			if (before != null)
+				return before;
+		} catch (ClassNotFoundException e) {
+			// That's ok. 
+		}
+		
+		cw.visit(Opcodes.V1_6, Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER, PACKAGE_NAME + "/" + className, 
+				"<TField:Ljava/lang/Object;>L" + COMPILED_CLASS + "<TTField;>;", 
+				COMPILED_CLASS, null);
+
+		createFields(cw, targetSignature);
+		createConstructor(cw, className, targetSignature, targetName);
+		createReadMethod(cw, className, source.getFields(), targetSignature, targetName);
+		createWriteMethod(cw, className, source.getFields(), targetSignature, targetName);
+		cw.visitEnd();
+
+		byte[] data = cw.toByteArray();
+		
+		// Call the define method
+		try {
+			if (defineMethod == null) {
+				Method defined = ClassLoader.class.getDeclaredMethod("defineClass", 
+					new Class<?>[] { String.class, byte[].class, int.class, int.class });
+			
+				// Awesome. Now, create and return it.
+				defined.setAccessible(true);
+				defineMethod = defined;
+			}
+			
+			@SuppressWarnings("rawtypes")
+			Class clazz = (Class) defineMethod.invoke(loader, null, data, 0, data.length);
+			
+			// DEBUG CODE: Print the content of the generated class.
+			//org.objectweb.asm.ClassReader cr = new org.objectweb.asm.ClassReader(data);
+	        //cr.accept(new ASMifierClassVisitor(new PrintWriter(System.out)), 0);
+			
+			return clazz;
+			
+		} catch (SecurityException e) {
+			throw new RuntimeException("Cannot use reflection to dynamically load a class.", e);
+		} catch (NoSuchMethodException e) {
+			throw new IllegalStateException("Incompatible JVM.", e);
+		} catch (IllegalArgumentException e) {
+			throw new IllegalStateException("Cannot call defineMethod - wrong JVM?", e);
+		} catch (IllegalAccessException e) {
+			throw new RuntimeException("Security limitation! Cannot dynamically load class.", e);
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException("Error occured in code generator.", e);
+		}
+	}
+	
+	/**
+	 * Determine if at least one of the given fields is public.
+	 * @param fields - field to test.
+	 * @return TRUE if one or more field is publically accessible, FALSE otherwise.
+	 */
+	private boolean isAnyPublic(List<Field> fields) {
+		// Are any of the fields public?
+		for (int i = 0; i < fields.size(); i++) {
+			if (isPublic(fields.get(i))) {
+				return true;
+			}
+		}
+		
+		return false;
+	}
+	
+	private boolean isPublic(Field field) {
+		return Modifier.isPublic(field.getModifiers());
+	}
+	
+	private void createFields(ClassWriter cw, String targetSignature) {
+		FieldVisitor typedField = cw.visitField(Opcodes.ACC_PRIVATE, "typedTarget", targetSignature, null, null);
+		typedField.visitEnd();
+	}
+	
+	private void createWriteMethod(ClassWriter cw, String className, List<Field> fields, String targetSignature, String targetName) {
+		
+		String methodDescriptor = "(ILjava/lang/Object;)L" + SUPER_CLASS + ";";
+		String methodSignature = "(ITTField;)L" + SUPER_CLASS + "<TTField;>;";
+		MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PROTECTED, "writeGenerated", methodDescriptor, methodSignature, 
+									new String[] { FIELD_EXCEPTION_CLASS });
+		BoxingHelper boxingHelper = new BoxingHelper(mv);
+		
+		mv.visitCode();
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitFieldInsn(Opcodes.GETFIELD, PACKAGE_NAME + "/" + className, "typedTarget", targetSignature);
+		mv.visitVarInsn(Opcodes.ASTORE, 3);
+		mv.visitVarInsn(Opcodes.ILOAD, 1);
+
+		// The last label is for the default switch
+		Label[] labels = new Label[fields.size()];
+		Label errorLabel = new Label();
+		Label returnLabel = new Label();
+		
+		// Generate labels
+		for (int i = 0; i < fields.size(); i++) {
+			labels[i] = new Label();
+		}
+		
+		mv.visitTableSwitchInsn(0, labels.length - 1, errorLabel, labels);
+		
+		for (int i = 0; i < fields.size(); i++) {
+			
+			Class<?> outputType = fields.get(i).getType();
+			Class<?> inputType = PrimitiveUtils.wrap(outputType);
+			String typeDescriptor = Type.getDescriptor(outputType);
+			String inputPath = inputType.getName().replace('.', '/');
+			
+			mv.visitLabel(labels[i]);
+			
+			// Push the compare object
+			if (i == 0)
+				mv.visitFrame(Opcodes.F_APPEND, 1, new Object[] { targetName }, 0, null);
+			else
+				mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+			
+			// Only write to public fields
+			if (isPublic(fields.get(i))) {
+				mv.visitVarInsn(Opcodes.ALOAD, 3);
+				mv.visitVarInsn(Opcodes.ALOAD, 2);
+				
+				if (!PrimitiveUtils.isPrimitive(outputType))
+					mv.visitTypeInsn(Opcodes.CHECKCAST, inputPath);
+				else
+					boxingHelper.unbox(Type.getType(outputType));
+				
+				mv.visitFieldInsn(Opcodes.PUTFIELD, targetName, fields.get(i).getName(), typeDescriptor);
+			
+			} else {
+				// Use reflection. We don't have a choice, unfortunately.
+				mv.visitVarInsn(Opcodes.ALOAD, 0);
+				mv.visitVarInsn(Opcodes.ILOAD, 1);
+				mv.visitVarInsn(Opcodes.ALOAD, 2);
+				mv.visitMethodInsn(Opcodes.INVOKESPECIAL, COMPILED_CLASS, "write", "(ILjava/lang/Object;)L" + SUPER_CLASS + ";");
+				mv.visitInsn(Opcodes.POP);
+			}
+		
+			mv.visitJumpInsn(Opcodes.GOTO, returnLabel);
+		}
+		
+		mv.visitLabel(errorLabel);
+		mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+		mv.visitTypeInsn(Opcodes.NEW, FIELD_EXCEPTION_CLASS);
+		mv.visitInsn(Opcodes.DUP);
+		mv.visitTypeInsn(Opcodes.NEW, "java/lang/StringBuilder");
+		mv.visitInsn(Opcodes.DUP);
+		mv.visitLdcInsn("Invalid index ");
+		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "(Ljava/lang/String;)V");
+		mv.visitVarInsn(Opcodes.ILOAD, 1);
+		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(I)Ljava/lang/StringBuilder;");
+		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;");
+		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, FIELD_EXCEPTION_CLASS, "<init>", "(Ljava/lang/String;)V");
+		mv.visitInsn(Opcodes.ATHROW);
+		
+		mv.visitLabel(returnLabel);
+		mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitInsn(Opcodes.ARETURN);
+		mv.visitMaxs(5, 4);
+		mv.visitEnd();
+	}
+
+	private void createReadMethod(ClassWriter cw, String className, List<Field> fields, String targetSignature, String targetName) {
+		MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PROTECTED, "readGenerated", "(I)Ljava/lang/Object;", null, 
+									new String[] { "com/comphenix/protocol/reflect/FieldAccessException" });
+		BoxingHelper boxingHelper = new BoxingHelper(mv);
+		
+		mv.visitCode();
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitFieldInsn(Opcodes.GETFIELD, PACKAGE_NAME + "/" + className, "typedTarget", targetSignature);
+		mv.visitVarInsn(Opcodes.ASTORE, 2);
+		mv.visitVarInsn(Opcodes.ILOAD, 1);
+
+		// The last label is for the default switch
+		Label[] labels = new Label[fields.size()];
+		Label errorLabel = new Label();
+		
+		// Generate labels
+		for (int i = 0; i < fields.size(); i++) {
+			labels[i] = new Label();
+		}
+		
+		mv.visitTableSwitchInsn(0, fields.size() - 1, errorLabel, labels);
+		
+		for (int i = 0; i < fields.size(); i++) {
+			Class<?> outputType = fields.get(i).getType();
+			String typeDescriptor = Type.getDescriptor(outputType);
+			
+			mv.visitLabel(labels[i]);
+			
+			// Push the compare object
+			if (i == 0)
+				mv.visitFrame(Opcodes.F_APPEND, 1, new Object[] { targetName }, 0, null);
+			else
+				mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+			
+			// Note that byte code cannot access non-public fields
+			if (isPublic(fields.get(i))) {
+				mv.visitVarInsn(Opcodes.ALOAD, 2);
+				mv.visitFieldInsn(Opcodes.GETFIELD, targetName, fields.get(i).getName(), typeDescriptor);
+				
+				boxingHelper.box(Type.getType(outputType));
+			} else {
+				// We have to use reflection for private and protected fields.
+				mv.visitVarInsn(Opcodes.ALOAD, 0);
+				mv.visitVarInsn(Opcodes.ILOAD, 1);
+				mv.visitMethodInsn(Opcodes.INVOKESPECIAL, COMPILED_CLASS, "read", "(I)Ljava/lang/Object;");
+			}
+			
+			mv.visitInsn(Opcodes.ARETURN);
+		}
+
+		mv.visitLabel(errorLabel);
+		mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+		mv.visitTypeInsn(Opcodes.NEW, FIELD_EXCEPTION_CLASS);
+		mv.visitInsn(Opcodes.DUP);
+		mv.visitTypeInsn(Opcodes.NEW, "java/lang/StringBuilder");
+		mv.visitInsn(Opcodes.DUP);
+		mv.visitLdcInsn("Invalid index ");
+		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "(Ljava/lang/String;)V");
+		mv.visitVarInsn(Opcodes.ILOAD, 1);
+		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(I)Ljava/lang/StringBuilder;");
+		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;");
+		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, FIELD_EXCEPTION_CLASS, "<init>", "(Ljava/lang/String;)V");
+		mv.visitInsn(Opcodes.ATHROW);
+		mv.visitMaxs(5, 3);
+		mv.visitEnd();
+	}
+
+	private void createConstructor(ClassWriter cw, String className, String targetSignature, String targetName) {
+		MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", 
+				"(L" + SUPER_CLASS + ";L" + PACKAGE_NAME + "/StructureCompiler;)V", 
+				"(L" + SUPER_CLASS + "<TTField;>;L" + SUPER_CLASS + ";)V", null);
+		mv.visitCode();
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitMethodInsn(Opcodes.INVOKESPECIAL, COMPILED_CLASS, "<init>", "()V");
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitVarInsn(Opcodes.ALOAD, 1);
+		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, PACKAGE_NAME + "/" + className, "initialize", "(L" + SUPER_CLASS + ";)V");
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitVarInsn(Opcodes.ALOAD, 1);
+		mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, SUPER_CLASS, "getTarget", "()Ljava/lang/Object;");
+		mv.visitFieldInsn(Opcodes.PUTFIELD, PACKAGE_NAME + "/" + className, "target", "Ljava/lang/Object;");
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitFieldInsn(Opcodes.GETFIELD, PACKAGE_NAME + "/" + className, "target", "Ljava/lang/Object;");
+		mv.visitTypeInsn(Opcodes.CHECKCAST, targetName);
+		mv.visitFieldInsn(Opcodes.PUTFIELD, PACKAGE_NAME + "/" + className, "typedTarget", targetSignature);
+		mv.visitVarInsn(Opcodes.ALOAD, 0);
+		mv.visitVarInsn(Opcodes.ALOAD, 2);
+		mv.visitFieldInsn(Opcodes.PUTFIELD, PACKAGE_NAME + "/" + className, "compiler", "L" + PACKAGE_NAME + "/StructureCompiler;");
+		mv.visitInsn(Opcodes.RETURN);
+		mv.visitMaxs(2, 3);
+		mv.visitEnd();
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/instances/CollectionGenerator.java

@@ -0,0 +1,51 @@
+package com.comphenix.protocol.reflect.instances;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Set;
+import java.util.SortedMap;
+import java.util.SortedSet;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+import javax.annotation.Nullable;
+
+/**
+ * Provides simple constructors for collection interfaces.
+ * @author Kristian
+ */
+public class CollectionGenerator implements InstanceProvider {
+
+	/**
+	 * Shared instance of this generator.
+	 */
+	public static CollectionGenerator INSTANCE = new CollectionGenerator();
+	
+	@Override
+	public Object create(@Nullable Class<?> type) {
+		// Standard collection types
+		if (type.isInterface()) {
+			if (type.equals(Collection.class) || type.equals(List.class))
+				return new ArrayList<Object>();
+			else if (type.equals(Set.class))
+				return new HashSet<Object>();
+			else if (type.equals(Map.class))
+				return new HashMap<Object, Object>();
+			else if (type.equals(SortedSet.class))
+				return new TreeSet<Object>();
+			else if (type.equals(SortedMap.class))
+				return new TreeMap<Object, Object>();
+			else if (type.equals(Queue.class))
+				return new LinkedList<Object>();
+		}
+		
+		// Cannot provide an instance
+		return null;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/instances/DefaultInstances.java

@@ -0,0 +1,244 @@
+/*
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2012 Kristian S. Stangeland
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the 
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 of 
+ *  the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ *  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program; 
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
+ *  02111-1307 USA
+ */
+
+package com.comphenix.protocol.reflect.instances;
+
+import java.lang.reflect.Constructor;
+import java.util.*;
+
+import net.sf.cglib.proxy.Enhancer;
+
+import com.google.common.base.Objects;
+import com.google.common.collect.ImmutableList;
+
+/**
+ * Used to construct default instances of any type.
+ * @author Kristian
+ *
+ */
+public class DefaultInstances {
+
+	/**
+	 * Standard default instance provider.
+	 */
+	public static DefaultInstances DEFAULT = DefaultInstances.fromArray(
+			PrimitiveGenerator.INSTANCE, CollectionGenerator.INSTANCE);
+		
+	/**
+	 * The maximum height of the hierachy of creates types. Used to prevent cycles.
+	 */
+	private final static int MAXIMUM_RECURSION = 20;
+	
+	/**
+	 * Ordered list of instance provider, from highest priority to lowest.
+	 */
+	private ImmutableList<InstanceProvider> registered;
+	
+	/**
+	 * Construct a default instance generator using the given instance providers.
+	 * @param registered - list of instance providers.
+	 */
+	public DefaultInstances(ImmutableList<InstanceProvider> registered) {
+		this.registered = registered;
+	}
+	
+	/**
+	 * Construct a default instance generator using the given instance providers.
+	 * @param instaceProviders - array of instance providers.
+	 */
+	public DefaultInstances(InstanceProvider... instaceProviders) {
+		this(ImmutableList.copyOf(instaceProviders));
+	}
+	
+	/**
+	 * Construct a default instance generator using the given instance providers.
+	 * @param instaceProviders - array of instance providers.
+	 * @return An default instance generator.
+	 */
+	public static DefaultInstances fromArray(InstanceProvider... instaceProviders) {
+		return new DefaultInstances(ImmutableList.copyOf(instaceProviders));
+	}
+	
+	/**
+	 * Retrieves a immutable list of every default object providers that generates instances.
+	 * @return Table of instance providers.
+	 */
+	public ImmutableList<InstanceProvider> getRegistered() {
+		return registered;
+	}
+	
+	/**
+	 * Retrieves a default instance or value that is assignable to this type.
+	 * <p>
+	 * This includes, but isn't limited too:
+	 * <ul>
+	 *   <li>Primitive types. Returns either zero or null.</li>
+	 *   <li>Primitive wrappers.</li>
+	 *   <li>String types. Returns an empty string.</li>
+	 *   <li>Arrays. Returns a zero-length array of the same type.</li>
+	 *   <li>Enums. Returns the first declared element.</li>
+	 *   <li>Collection interfaces, such as List and Set. Returns the most appropriate empty container.</li>
+	 *   <li>Any type with a public constructor that has parameters with defaults.</li>
+	 *   </ul>
+	 * </ul>
+	 * @param type - the type to construct a default value.
+	 * @return A default value/instance, or NULL if not possible.
+	 */
+	public <T> T getDefault(Class<T> type) {
+		return getDefaultInternal(type, registered, 0);
+	}
+	
+	/**
+	 * Retrieve the constructor with the fewest number of parameters.
+	 * @param type - type to construct.
+	 * @return A constructor with the fewest number of parameters, or NULL if the type has no constructors.
+	 */
+	@SuppressWarnings("unchecked")
+	public <T> Constructor<T> getMinimumConstructor(Class<T> type) {
+		
+		Constructor<T> minimum = null;
+		int lastCount = Integer.MAX_VALUE;
+		
+		// Find the constructor with the fewest parameters
+		for (Constructor<?> candidate : type.getConstructors()) {
+			Class<?>[] types = candidate.getParameterTypes();
+			
+			// Note that we don't allow recursive types - that is, types that
+			// require itself in the constructor.
+			if (types.length < lastCount) {
+				if (!contains(types, type)) {
+					minimum = (Constructor<T>) candidate;
+					lastCount = types.length;
+					
+					// Don't loop again if we've already found the best possible constructor
+					if (lastCount == 0)
+						break;
+				}
+			}
+		}
+		
+		return minimum;
+	}
+	
+	/**
+	 * Retrieves a default instance or value that is assignable to this type.
+	 * <p>
+	 * This includes, but isn't limited too:
+	 * <ul>
+	 *   <li>Primitive types. Returns either zero or null.</li>
+	 *   <li>Primitive wrappers.</li>
+	 *   <li>String types. Returns an empty string.</li>
+	 *   <li>Arrays. Returns a zero-length array of the same type.</li>
+	 *   <li>Enums. Returns the first declared element.</li>
+	 *   <li>Collection interfaces, such as List and Set. Returns the most appropriate empty container.</li>
+	 *   <li>Any type with a public constructor that has parameters with defaults.</li>
+	 *   </ul>
+	 * </ul>
+	 * @param type - the type to construct a default value.
+	 * @param providers - instance providers used during the 
+	 * @return A default value/instance, or NULL if not possible.
+	 */
+	public <T> T getDefault(Class<T> type, List<InstanceProvider> providers) {
+		return getDefaultInternal(type, providers, 0);
+	}
+	
+	@SuppressWarnings("unchecked")
+	private <T> T getDefaultInternal(Class<T> type, List<InstanceProvider> providers, int recursionLevel) {
+		
+		// Guard against recursion
+		if (recursionLevel > MAXIMUM_RECURSION) {
+			return null;
+		}
+		
+		for (InstanceProvider generator : providers) {
+			Object value = generator.create(type);
+			
+			if (value != null)
+				return (T) value;
+		}
+
+		Constructor<T> minimum = getMinimumConstructor(type);
+
+		// Create the type with this constructor using default values. This might fail, though.
+		try {
+			if (minimum != null) {
+				int parameterCount = minimum.getParameterTypes().length;
+				Object[] params = new Object[parameterCount];
+				Class<?>[] types = minimum.getParameterTypes();
+				
+				// Fill out 
+				for (int i = 0; i < parameterCount; i++) {
+					params[i] = getDefaultInternal(types[i], providers, recursionLevel + 1);
+				}
+				
+				return createInstance(type, minimum, types, params);
+			}
+			
+		} catch (Exception e) {
+			// Nope, we couldn't create this type
+		}
+		
+		// No suitable default value could be found
+		return null;
+	}
+	
+	/**
+	 * Construct default instances using the CGLIB enhancer object instead.
+	 * @param enhancer - a CGLIB enhancer to use.
+	 * @return A default instance generator that uses the CGLIB enhancer.
+	 */
+	public DefaultInstances forEnhancer(Enhancer enhancer) {
+		final Enhancer ex = enhancer;
+		
+		return new DefaultInstances(registered) {
+			@SuppressWarnings("unchecked")
+			@Override
+			protected <T> T createInstance(Class<T> type, Constructor<T> constructor, Class<?>[] types, Object[] params) {
+				// Use the enhancer instead
+				return (T) ex.create(types, params);
+			}
+		};
+	}
+	
+	/**
+	 * Used by the default instance provider to create a class from a given constructor. 
+	 * The default method uses reflection.
+	 * @param type - the type to create.
+	 * @param constructor - the constructor to use.
+	 * @param types - type of each parameter in order.
+	 * @param params - value of each parameter in order.
+	 * @return The constructed instance.
+	 */
+	protected <T> T createInstance(Class<T> type, Constructor<T> constructor, Class<?>[] types, Object[] params) {
+		try {
+			return (T) constructor.newInstance(params);
+		} catch (Exception e) {
+			// Cannot create it
+			return null;
+		}
+	}
+	
+	// We avoid Apache's utility methods to stay backwards compatible
+	protected <T> boolean contains(T[] elements, T elementToFind) {
+		// Search for the given element in the array
+		for (T element : elements) {
+			if (Objects.equal(elementToFind, element))
+				return true;
+		}
+		return false;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/instances/ExistingGenerator.java

@@ -0,0 +1,89 @@
+package com.comphenix.protocol.reflect.instances;
+
+import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
+import com.comphenix.protocol.reflect.FieldUtils;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+
+/**
+ * Provides instance constructors using a list of existing values.
+ * <p>
+ * Only one instance per individual class.
+ * @author Kristian
+ */
+public class ExistingGenerator implements InstanceProvider {
+
+	@SuppressWarnings("rawtypes")
+	private Map<Class, Object> existingValues = new HashMap<Class, Object>();
+	
+	private ExistingGenerator() {
+		// Only accessible to the constructors
+	}
+	
+	/**
+	 * Automatically create an instance provider from a objects public and private fields.
+	 * <p>
+	 * If two or more fields share the same type, the last declared non-null field will take
+	 * precedent.
+	 * @param object - object to create an instance generator from.
+	 * @return The instance generator.
+	 */
+	public static ExistingGenerator fromObjectFields(Object object) {
+		ExistingGenerator generator = new ExistingGenerator();
+		
+		// Read instances from every field.
+		for (Field field : FuzzyReflection.fromObject(object, true).getFields()) {
+			try {
+				Object value = FieldUtils.readField(field, object, true);
+				
+				// Use the type of the field, not the object itself
+				if (value != null)
+					generator.addObject(field.getType(), value);
+				
+			} catch (Exception e) {
+				// Yes, swallow it. No, really.
+			}
+		}
+		
+		return generator;
+	}
+	
+	/**
+	 * Create an instance generator from a pre-defined array of values.
+	 * @param values - values to provide.
+	 * @return An instance provider that uses these values.
+	 */
+	public static ExistingGenerator fromObjectArray(Object[] values) {
+		ExistingGenerator generator = new ExistingGenerator();
+		
+		for (Object value : values)
+			 generator.addObject(value);
+		
+		return generator;
+	}
+	
+	private void addObject(Object value) {
+		if (value == null)
+			throw new IllegalArgumentException("Value cannot be NULL.");
+		
+		existingValues.put(value.getClass(), value);
+	}
+
+	private void addObject(Class<?> type, Object value) {
+		existingValues.put(type, value);
+	}
+
+	
+	@Override
+	public Object create(@Nullable Class<?> type) {
+		
+		Object value = existingValues.get(type);
+		
+		// NULL values indicate that the generator failed
+		return value;
+	}
+}

ProtocolLib/src/com/comphenix/protocol/reflect/instances/InstanceProvider.java

@@ -0,0 +1,18 @@
+package com.comphenix.protocol.reflect.instances;
+
+import javax.annotation.Nullable;
+
+/**
+ * Represents a type generator for specific types.
+ * 
+ * @author Kristian
+ */
+public interface InstanceProvider {
+
+	/**
+	 * Create an instance given a type, if possible.
+	 * @param type - type to create.
+	 * @return The instance, or NULL if the type cannot be created.
+	 */
+	public abstract Object create(@Nullable Class<?> type);
+}

ProtocolLib/src/com/comphenix/protocol/reflect/instances/PrimitiveGenerator.java

@@ -0,0 +1,62 @@
+package com.comphenix.protocol.reflect.instances;
+
+import java.lang.reflect.Array;
+
+import javax.annotation.Nullable;
+
+import com.comphenix.protocol.reflect.PrimitiveUtils;
+import com.google.common.base.Defaults;
+
+/**
+ * Provides constructors for primtive types, wrappers, arrays and strings.
+ * @author Kristian
+ */
+public class PrimitiveGenerator implements InstanceProvider {
+	
+	/**
+	 * Default value for Strings.
+	 */
+	public static final String STRING_DEFAULT = "";
+	
+	/**
+	 * Shared instance of this generator.
+	 */
+	public static PrimitiveGenerator INSTANCE = new PrimitiveGenerator(STRING_DEFAULT);
+
+	// Our default string value
+	private String stringDefault;
+	
+	public PrimitiveGenerator(String stringDefault) {
+		this.stringDefault = stringDefault;
+	}
+	
+	/**
+	 * Retrieve the string default.
+	 * @return Default instance of a string.
+	 */
+	public String getStringDefault() {
+		return stringDefault;
+	}
+
+	@Override
+	public Object create(@Nullable Class<?> type) {
+		
+		if (PrimitiveUtils.isPrimitive(type)) {
+			return Defaults.defaultValue(type);
+		} else if (PrimitiveUtils.isWrapperType(type)) {
+			return Defaults.defaultValue(PrimitiveUtils.unwrap(type));
+		} else if (type.isArray()) {
+			Class<?> arrayType = type.getComponentType();
+			return Array.newInstance(arrayType, 0);
+		} else if (type.isEnum()) {
+			Object[] values = type.getEnumConstants();
+			if (values != null && values.length > 0)
+				return values[0];
+		} else if (type.equals(String.class)) {
+			return stringDefault;
+		} 
+		
+		// Cannot handle this type
+		return null;
+	}	
+}

ProtocolLib/src/plugin.yml

@@ -1,5 +1,5 @@
 name: ProtocolLib
-version: 1.0.0
+version: 1.2.0
 description: Provides read/write access to the Minecraft protocol.
 author: Comphenix
 website: http://www.comphenix.net/ProtocolLib

ProtocolLib/test/com/comphenix/protocol/injector/SortedCopyOnWriteArrayTest.java

@@ -0,0 +1,77 @@
+package com.comphenix.protocol.injector;
+
+import static org.junit.Assert.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Test;
+
+import com.comphenix.protocol.concurrency.SortedCopyOnWriteArray;
+import com.comphenix.protocol.events.ListenerPriority;
+import com.google.common.primitives.Ints;
+
+public class SortedCopyOnWriteArrayTest {
+
+	@Test
+	public void testInsertion() {
+		
+		final int MAX_NUMBER = 50;
+
+		SortedCopyOnWriteArray<Integer> test = new SortedCopyOnWriteArray<Integer>();
+		
+		// Generate some numbers
+		List<Integer> numbers = new ArrayList<Integer>();
+		
+		for (int i = 0; i < MAX_NUMBER; i++) {
+			numbers.add(i);
+		}
+		
+		// Random insertion to test it all
+		Collections.shuffle(numbers);
+		
+		// O(n^2) of course, so don't use too large numbers
+		for (int i = 0; i < MAX_NUMBER; i++) {
+			test.add(numbers.get(i));
+		}
+		
+		// Check that everything is correct
+		for (int i = 0; i < MAX_NUMBER; i++) {
+			assertEquals((Integer) i, test.get(i));
+		}
+	}
+	
+	@Test
+	public void testOrder() {
+		PriorityStuff a = new PriorityStuff(ListenerPriority.HIGH, 1);
+		PriorityStuff b = new PriorityStuff(ListenerPriority.NORMAL, 2);
+		PriorityStuff c = new PriorityStuff(ListenerPriority.NORMAL, 3);
+		SortedCopyOnWriteArray<PriorityStuff> test = new SortedCopyOnWriteArray<PriorityStuff>();
+		
+		test.add(a);
+		test.add(b);
+		test.add(c);
+		
+		// Make sure the normal's are in the right order
+		assertEquals(2, test.get(0).id);
+		assertEquals(3, test.get(1).id);
+	}
+	
+	private class PriorityStuff implements Comparable<PriorityStuff> {
+		public ListenerPriority priority;
+		public int id;
+
+		public PriorityStuff(ListenerPriority priority, int id) {
+			this.priority = priority;
+			this.id = id;
+		}
+
+		@Override
+		public int compareTo(PriorityStuff other) {
+			// This ensures that lower priority listeners are executed first
+			return Ints.compare(priority.getSlot(),
+					            other.priority.getSlot());
+		}
+	}
+}

ProtocolLib/test/com/comphenix/protocol/reflect/StructureModifierTest.java

@@ -6,15 +6,17 @@ import net.minecraft.server.Packet103SetSlot;
 
 import org.junit.Test;
 
+import com.avaje.ebeaninternal.server.cluster.Packet;
 import com.comphenix.protocol.reflect.StructureModifier;
 
 public class StructureModifierTest {
 
 	@Test
-	public void test() throws IllegalAccessException {
+	public void test() throws FieldAccessException {
 
 		Packet103SetSlot move = new Packet103SetSlot();
-		StructureModifier<Object> modifier = new StructureModifier<Object>(Packet103SetSlot.class);
+		StructureModifier<Object> modifier = new StructureModifier<Object>(
+				Packet103SetSlot.class, Packet.class, true);
 
 		move.a = 1;
 		int value = (Integer) modifier.withTarget(move).withType(int.class).read(0);

Readme.md

@@ -0,0 +1,131 @@
+ProtocolLib 
+===========
+
+Certain tasks are impossible to perform with the standard Bukkit API, and may require 
+working with and even modify Minecraft directly. A common technique is to modify incoming 
+and outgoing [packets](http://www.wiki.vg/Protocol), or inject custom packets into the
+stream. This is quite cumbersome to do, however, and most implementations will break 
+as soon as a new version of Minecraft has been released, mostly due to obfuscation.
+
+Critically, different plugins that use this approach may _hook_ into the same classes, 
+with unpredictable outcomes. More than often this causes plugins to crash, but it may also 
+lead to more subtle bugs.
+
+
+### Resources
+
+* [JavaDoc](http://aadnk.github.com/ProtocolLib/Javadoc/) 
+
+
+A new API
+---------
+
+__ProtocolLib__ attempts to solve this problem by providing a event API, much like Bukkit, 
+that allow plugins to monitor, modify or cancel packets sent and received. But more importantly, 
+the API also hides all the gritty, obfuscated classes with a simple index based read/write system. 
+You no longer have to reference CraftBukkit!
+
+
+### Using ProtocolLib
+
+To use the library, first add ProtocolLib.jar to your Java build path. Then, add ProtocolLib
+as a dependency (or soft-dependency, if you can live without it) to your plugin.yml file:
+
+    depends: [ProtocolLib]
+
+Then get a reference to ProtocolManager in onLoad() and you're good to go.
+
+    private ProtocolManager protocolManager;
+    
+    public void onLoad() {
+        protocolManager = ProtocolLibrary.getProtocolManager();
+    }
+
+To listen for packets sent by the server to a client, add a server-side listener:
+
+    // Disable all sound effects
+    protocolManager.addPacketListener(
+      new PacketAdapter(this, ConnectionSide.SERVER_SIDE, ListenerPriority.NORMAL, 0x3E) {
+        @Override
+        public void onPacketSending(PacketEvent event) {
+            // Item packets
+            switch (event.getPacketID()) {
+            case 0x3E: // Sound effect
+                event.setCancelled(true);
+                break;
+            }
+        }
+    });
+
+
+It's also possible to read and modify the content of these packets. For instance, you can create a global
+censor by listening for Packet3Chat events:
+
+    // Censor
+    protocolManager.addPacketListener(
+      new PacketAdapter(this, ConnectionSide.CLIENT_SIDE, ListenerPriority.NORMAL, 0x03) {
+        @Override
+        public void onPacketReceiving(PacketEvent event) {
+            if (event.getPacketID() == 0x03) {
+                try {
+                    PacketContainer packet = event.getPacket();
+                    String message = packet.getSpecificModifier(String.class).read(0);
+                    
+                    if (message.contains("shit") || message.contains("damn")) {
+                        event.setCancelled(true);
+                        event.getPlayer().sendMessage("Bad manners!");
+                    }
+                    		
+                } catch (FieldAccessException e) {
+                    getLogger().log(Level.SEVERE, "Couldn't access field.", e);
+                }
+            }
+        }
+    });
+
+
+### Sending packets
+
+Normally, you might have to do something ugly like the following:
+
+    Packet60Explosion fakeExplosion = new Packet60Explosion();
+    	
+    fakeExplosion.a = player.getLocation().getX();
+    fakeExplosion.b = player.getLocation().getY();
+    fakeExplosion.c = player.getLocation().getZ();
+    fakeExplosion.d = 3.0F;
+    fakeExplosion.e = new ArrayList<Object>();
+
+    ((CraftPlayer) player).getHandle().netServerHandler.sendPacket(fakeExplosion);
+
+But with ProtocolLib, you can turn that into something more manageable. Notice that 
+you don't have to create an ArrayList this version:
+
+    PacketContainer fakeExplosion = protocolManager.createPacket(60);
+    
+    fakeExplosion.getSpecificModifier(double.class).
+        write(0, player.getLocation().getX()).
+        write(1, player.getLocation().getY()).
+        write(2, player.getLocation().getZ());
+    fakeExplosion.getSpecificModifier(float.class).
+        write(0, 3.0F);
+    
+    protocolManager.sendServerPacket(player, fakeExplosion);
+
+
+Compatiblity
+------------
+
+One of the main goals of this project was to achive maximum compatibility with craftBukkit. And the end
+result is quite flexible - in tests I successfully ran an unmodified ProtocolLib on CraftBukkit 1.8.0, and
+it should be resiliant against future changes. It's likely that I won't have to update ProtocolLib for
+anything but bug and performance fixes. 
+
+How is this possible? It all comes down to reflection in the end. Essentially, no name is hard coded - 
+every field, method and class is deduced by looking at field types, package names or parameter
+types. It's remarkably consistent across different versions.
+
+
+### Incompatiblity
+
+The following plugins (to be expanded) are not compatible with ProtocolLib: