Remove ability to unload default worlds.

Small WorldManager updates

pom.xml

@@ -215,7 +215,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>3.1.1</version>
+                <version>3.2.4</version>
                 <executions>
                     <execution>
                         <phase>package</phase>
@@ -264,13 +264,19 @@
             <plugin>
                 <groupId>se.eris</groupId>
                 <artifactId>notnull-instrumenter-maven-plugin</artifactId>
-                <version>0.6.8</version>
+                <version>1.0.0</version>
                 <executions>
                     <execution>
                         <goals>
                             <goal>instrument</goal>
                             <goal>tests-instrument</goal>
                         </goals>
+                        <configuration>
+                            <notNull>
+                                <param>org.jetbrains.annotations.NotNull</param>
+                                <param>javax.validation.constraints.NotNull</param>
+                            </notNull>
+                        </configuration>
                     </execution>
                 </executions>
             </plugin>
@@ -319,7 +325,7 @@
         <dependency>
             <groupId>org.bstats</groupId>
             <artifactId>bstats-bukkit</artifactId>
-            <version>1.7</version>
+            <version>1.8</version>
             <exclusions>
                 <exclusion>
                     <groupId>org.bukkit</groupId>
@@ -353,21 +359,21 @@
         <dependency>
             <groupId>org.powermock</groupId>
             <artifactId>powermock-module-junit4</artifactId>
-            <version>2.0.0</version>
+            <version>2.0.9</version>
             <type>jar</type>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.powermock</groupId>
             <artifactId>powermock-api-easymock</artifactId>
-            <version>2.0.0</version>
+            <version>2.0.9</version>
             <type>jar</type>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.powermock</groupId>
             <artifactId>powermock-api-mockito2</artifactId>
-            <version>2.0.0</version>
+            <version>2.0.9</version>
             <type>jar</type>
             <scope>test</scope>
         </dependency>

src/main/java/com/onarandombox/MultiverseCore/MultiverseCore.java

@@ -88,6 +88,7 @@ import com.onarandombox.MultiverseCore.listeners.MVWeatherListener;
 import com.onarandombox.MultiverseCore.listeners.MVWorldInitListener;
 import com.onarandombox.MultiverseCore.listeners.MVWorldListener;
 import com.onarandombox.MultiverseCore.utils.AnchorManager;
+import com.onarandombox.MultiverseCore.utils.CompatibilityLayer;
 import com.onarandombox.MultiverseCore.utils.MVEconomist;
 import com.onarandombox.MultiverseCore.utils.MVMessaging;
 import com.onarandombox.MultiverseCore.utils.MVPermissions;
@@ -128,9 +129,9 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
     private static final int PROTOCOL = 24;
     // TODO: Investigate if this one is really needed to be static.
     // Doubt it. -- FernFerret
-    private static final Map<String, String> teleportQueue = new HashMap<String, String>();
+    private static Map<String, String> teleportQueue = new HashMap<String, String>();
 
-    private final AnchorManager anchorManager = new AnchorManager(this);
+    private AnchorManager anchorManager = new AnchorManager(this);
     // TODO please let's make this non-static
     private volatile MultiverseCoreConfiguration config;
 
@@ -254,6 +255,8 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
         // Setup our SafeTTeleporter
         this.safeTTeleporter = new SimpleSafeTTeleporter(this);
         this.unsafeCallWrapper = new UnsafeCallWrapper(this);
+        // Setup our CompatibilityLayer
+        CompatibilityLayer.init();
     }
 
 
@@ -353,13 +356,16 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
      * Initializes the buscript javascript library.
      */
     private void initializeBuscript() {
-        try {
-            buscript = new Buscript(this);
-            // Add global variable "multiverse" to javascript environment
-            buscript.setScriptVariable("multiverse", this);
-        } catch (NullPointerException e) {
-            buscript = null;
-            Logging.warning("Buscript failed to load! The script command will be disabled!");
+        buscript = null;
+
+        if (this.getMVConfig().getEnableBuscript()) {
+            try {
+                buscript = new Buscript(this);
+                // Add global variable "multiverse" to javascript environment
+                buscript.setScriptVariable("multiverse", this);
+            } catch (NullPointerException e) {
+                Logging.warning("Buscript failed to load! The script command will be disabled!");
+            }
         }
     }
 

src/main/java/com/onarandombox/MultiverseCore/MultiverseCoreConfiguration.java

@@ -56,6 +56,8 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
     @Property
     private volatile boolean displaypermerrors;
     @Property
+    private volatile boolean enablebuscript;
+    @Property
     private volatile int globaldebug;
     @Property
     private volatile boolean silentstart;
@@ -99,6 +101,7 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
         teleportintercept = true;
         firstspawnoverride = true;
         displaypermerrors = true;
+        enablebuscript = true;
         globaldebug = 0;
         messagecooldown = 5000;
         teleportcooldown = 1000;
@@ -213,6 +216,22 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
         return this.displaypermerrors;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean getEnableBuscript() {
+        return this.enablebuscript;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void setEnableBuscript(boolean enableBuscript) {
+        this.enablebuscript = enableBuscript;
+    }
+
     /**
      * {@inheritDoc}
      */

src/main/java/com/onarandombox/MultiverseCore/api/MVWorldManager.java

@@ -174,6 +174,16 @@ public interface MVWorldManager {
      */
     MultiverseWorld getMVWorld(String name);
 
+    /**
+     * Returns a {@link MultiverseWorld} if the world with name given exists, and null if it does not.
+     * This will search optionally for alias names.
+     *
+     * @param name          The name or optionally the alias of the world to get.
+     * @param checkAliases  Indicates whether to check for world alias name.
+     * @return A {@link MultiverseWorld} or null.
+     */
+    MultiverseWorld getMVWorld(String name, boolean checkAliases);
+
     /**
      * Returns a {@link MultiverseWorld} if it exists, and null if it does not.
      *
@@ -183,13 +193,24 @@ public interface MVWorldManager {
     MultiverseWorld getMVWorld(World world);
 
     /**
-     * Checks to see if the given name is a valid {@link MultiverseWorld}.
+     * Checks to see if the given name is a valid {@link MultiverseWorld}
+     * Searches based on world name AND alias.
      *
      * @param name The name or alias of the world to check.
      * @return True if the world exists, false if not.
      */
     boolean isMVWorld(String name);
 
+    /**
+     * Checks to see if the given name is a valid {@link MultiverseWorld}.
+     * Optionally searches by alias is specified.
+     *
+     * @param name          The name or alias of the world to check.
+     * @param checkAliases  Indicates whether to check for world alias name.
+     * @return True if the world exists, false if not.
+     */
+    boolean isMVWorld(String name, boolean checkAliases);
+
     /**
      * Checks to see if the given world is a valid {@link MultiverseWorld}.
      *
@@ -198,6 +219,38 @@ public interface MVWorldManager {
      */
     boolean isMVWorld(World world);
 
+    /**
+     * Checks if a world name is the servers default world.
+     *
+     * Generally, default world is defined in level-name of server properties file along with
+     * it's 2 dimensions: [world]_nether, [world]_the_end.
+     *
+     * @param world The world to check.
+     * @return True if world name is a default world, else false.
+     */
+    boolean isDefaultWorld(MultiverseWorld world);
+
+    /**
+     * Checks if a world name is the servers default world.
+     *
+     * Generally, default world is defined in level-name of server properties file along with
+     * it's 2 dimensions: [world]_nether, [world]_the_end.
+     *
+     * @param worldName The name of the world to check.
+     * @return True if world name is a default world, else false.
+     */
+    boolean isDefaultWorld(String worldName);
+
+    /**
+     * Gets all the default world names of the server.
+     *
+     * Generally, default world is defined in level-name of server properties file along with
+     * it's 2 dimensions: [world]_nether, [world]_the_end.
+     *
+     * @return Collection of default world names.
+     */
+    Collection<String> getDefaultWorldNames();
+
     /**
      * Load the Worlds &amp; Settings from the configuration file.
      *
@@ -314,4 +367,11 @@ public interface MVWorldManager {
      * does not exist. {@code includeLoaded} if the world exists and is loaded.
      */
     boolean hasUnloadedWorld(String name, boolean includeLoaded);
+
+    /**
+     * Get all the possible worlds that Multiverse has detected to be importable.
+     *
+     * @return A collection of world names that are deemed importable.
+     */
+    Collection<String> getPotentialWorlds();
 }

src/main/java/com/onarandombox/MultiverseCore/api/MultiverseCoreConfig.java

@@ -86,6 +86,18 @@ public interface MultiverseCoreConfig extends ConfigurationSerializable {
      */
     boolean getDisplayPermErrors();
 
+    /**
+     * Sets enableBuscript.
+     * @param enableBuscript The new value.
+     */
+    void setEnableBuscript(boolean enableBuscript);
+
+    /**
+     * Gets enableBuscript.
+     * @return enableBuscript.
+     */
+    boolean getEnableBuscript();
+
     /**
      * Sets firstSpawnOverride.
      * @param firstSpawnOverride The new value.

src/main/java/com/onarandombox/MultiverseCore/commands/CheckCommand.java

@@ -11,6 +11,7 @@ import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MVDestination;
 import com.onarandombox.MultiverseCore.destination.InvalidDestination;
 import com.onarandombox.MultiverseCore.utils.MVPermissions;
+import com.onarandombox.MultiverseCore.utils.PlayerFinder;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
@@ -37,7 +38,7 @@ public class CheckCommand extends MultiverseCommand {
 
     @Override
     public void runCommand(CommandSender sender, List<String> args) {
-        Player p = this.plugin.getServer().getPlayerExact(args.get(0));
+        Player p = PlayerFinder.get(args.get(0), sender);
         if (p == null) {
             sender.sendMessage("Could not find player " + ChatColor.GREEN + args.get(0));
             sender.sendMessage("Are they online?");

src/main/java/com/onarandombox/MultiverseCore/commands/CloneCommand.java

@@ -20,7 +20,7 @@ import com.onarandombox.MultiverseCore.api.MVWorldManager;
  * Creates a clone of a world.
  */
 public class CloneCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public CloneCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/ConfigCommand.java

@@ -19,7 +19,6 @@ import java.util.Map;
  * Allows you to set Global MV Variables.
  */
 public class ConfigCommand extends MultiverseCommand {
-
     public ConfigCommand(MultiverseCore plugin) {
         super(plugin);
         this.setName("Configuration");

src/main/java/com/onarandombox/MultiverseCore/commands/CoordCommand.java

@@ -24,7 +24,7 @@ import java.util.List;
  * Returns detailed information on the Players where abouts.
  */
 public class CoordCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public CoordCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/CreateCommand.java

@@ -26,7 +26,7 @@ import java.util.List;
  * Creates a new world and loads it.
  */
 public class CreateCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public CreateCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/ImportCommand.java

@@ -9,7 +9,7 @@ package com.onarandombox.MultiverseCore.commands;
 
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MVWorldManager;
-import com.onarandombox.MultiverseCore.api.MultiverseWorld;
+import com.onarandombox.MultiverseCore.utils.WorldNameChecker;
 import com.pneumaticraft.commandhandler.CommandHandler;
 import org.bukkit.ChatColor;
 import org.bukkit.World.Environment;
@@ -18,8 +18,6 @@ import org.bukkit.command.CommandSender;
 import org.bukkit.permissions.PermissionDefault;
 
 import java.io.File;
-import java.io.FilenameFilter;
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 
@@ -45,55 +43,17 @@ public class ImportCommand extends MultiverseCommand {
         this.worldManager = this.plugin.getMVWorldManager();
     }
 
-    /**
-     * A very basic check to see if a folder has a level.dat file.
-     * If it does, we can safely assume it's a world folder.
-     *
-     * @param worldFolder The File that may be a world.
-     * @return True if it looks like a world, false if not.
-     */
-    private static boolean checkIfIsWorld(File worldFolder) {
-        if (worldFolder.isDirectory()) {
-            File[] files = worldFolder.listFiles(new FilenameFilter() {
-                @Override
-                public boolean accept(File file, String name) {
-                    return name.toLowerCase().endsWith(".dat");
-                }
-            });
-            if (files != null && files.length > 0) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    private String getPotentialWorlds() {
-        File worldFolder = this.plugin.getServer().getWorldContainer();
-        if (worldFolder == null) {
-            return "";
-        }
-        File[] files = worldFolder.listFiles();
-        String worldList = "";
-        Collection<MultiverseWorld> worlds = this.worldManager.getMVWorlds();
-        List<String> worldStrings = new ArrayList<String>();
-        for (MultiverseWorld world : worlds) {
-            worldStrings.add(world.getName());
-        }
-        for (String world : this.worldManager.getUnloadedWorlds()) {
-            worldStrings.add(world);
-        }
+    private String getPotentialWorldStrings() {
+        final Collection<String> potentialWorlds = this.worldManager.getPotentialWorlds();
+        StringBuilder worldList = new StringBuilder();
         ChatColor currColor = ChatColor.WHITE;
-        for (File file : files) {
-            if (file.isDirectory() && checkIfIsWorld(file) && !worldStrings.contains(file.getName())) {
-                worldList += currColor + file.getName() + " ";
-                if (currColor == ChatColor.WHITE) {
-                    currColor = ChatColor.YELLOW;
-                } else {
-                    currColor = ChatColor.WHITE;
-                }
-            }
+
+        for (String world : potentialWorlds) {
+            worldList.append(currColor).append(world).append(' ');
+            currColor = currColor == ChatColor.WHITE ? ChatColor.YELLOW : ChatColor.WHITE;
         }
-        return worldList;
+
+        return worldList.toString();
     }
     
     private String trimWorldName(String userInput) {
@@ -106,7 +66,7 @@ public class ImportCommand extends MultiverseCommand {
         String worldName = trimWorldName(args.get(0));
 
         if (worldName.toLowerCase().equals("--list") || worldName.toLowerCase().equals("-l")) {
-            String worldList = this.getPotentialWorlds();
+            String worldList = this.getPotentialWorldStrings();
             if (worldList.length() > 2) {
                 sender.sendMessage(ChatColor.AQUA + "====[ These look like worlds ]====");
                 sender.sendMessage(worldList);
@@ -149,10 +109,10 @@ public class ImportCommand extends MultiverseCommand {
 
         if (!worldFile.exists()) {
             sender.sendMessage(ChatColor.RED + "FAILED.");
-            String worldList = this.getPotentialWorlds();
+            String worldList = this.getPotentialWorldStrings();
             sender.sendMessage("That world folder does not exist. These look like worlds to me:");
             sender.sendMessage(worldList);
-        } else if (!checkIfIsWorld(worldFile)) {
+        } else if (!WorldNameChecker.isValidWorldFolder(worldFile)) {
             sender.sendMessage(ChatColor.RED + "FAILED.");
             sender.sendMessage(String.format("'%s' does not appear to be a world. It is lacking a .dat file.",
                                              worldName));

src/main/java/com/onarandombox/MultiverseCore/commands/InfoCommand.java

@@ -30,7 +30,7 @@ import java.util.List;
  * Returns detailed information about a world.
  */
 public class InfoCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public InfoCommand(MultiverseCore plugin) {
         super(plugin);
@@ -115,6 +115,7 @@ public class InfoCommand extends MultiverseCommand {
         FancyColorScheme colors = new FancyColorScheme(ChatColor.AQUA, ChatColor.AQUA, ChatColor.GOLD, ChatColor.WHITE);
         message.add(new FancyHeader("General Info", colors));
         message.add(new FancyMessage("World Name: ", world.getName(), colors));
+        message.add(new FancyMessage("World UID: ", world.getCBWorld().getUID().toString(), colors));
         message.add(new FancyMessage("World Alias: ", world.getColoredWorldString(), colors));
         message.add(new FancyMessage("Game Mode: ", world.getGameMode().toString(), colors));
         message.add(new FancyMessage("Difficulty: ", world.getDifficulty().toString(), colors));
@@ -151,6 +152,7 @@ public class InfoCommand extends MultiverseCommand {
         message = new ArrayList<FancyText>();
         message.add(new FancyHeader("More World Settings", colors));
         message.add(new FancyMessage("World Type: ", world.getWorldType().toString(), colors));
+        message.add(new FancyMessage("Generator: ", world.getGenerator(), colors));
         message.add(new FancyMessage("Structures: ", world.getCBWorld().canGenerateStructures() + "", colors));
         message.add(new FancyMessage("Weather: ", world.isWeatherEnabled() + "", colors));
         message.add(new FancyMessage("Players will get hungry: ", world.getHunger() + "", colors));

src/main/java/com/onarandombox/MultiverseCore/commands/ModifyAddCommand.java

@@ -25,7 +25,7 @@ import java.util.List;
  * Used to modify various aspects of worlds.
  */
 public class ModifyAddCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public ModifyAddCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/ModifyClearCommand.java

@@ -22,7 +22,7 @@ import java.util.List;
  * Removes all values from a world-property.
  */
 public class ModifyClearCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public ModifyClearCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/ModifyRemoveCommand.java

@@ -22,7 +22,7 @@ import java.util.List;
  * Removes values from a world-property.
  */
 public class ModifyRemoveCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public ModifyRemoveCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/ModifySetCommand.java

@@ -23,7 +23,7 @@ import java.util.List;
  * Used to set world-properties.
  */
 public class ModifySetCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public ModifySetCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/PurgeCommand.java

@@ -24,7 +24,7 @@ import java.util.List;
  * Removes a type of mob from a world.
  */
 public class PurgeCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+    private MVWorldManager worldManager;
 
     public PurgeCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/commands/SpawnCommand.java

@@ -9,6 +9,7 @@ package com.onarandombox.MultiverseCore.commands;
 
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MultiverseWorld;
+import com.onarandombox.MultiverseCore.utils.PlayerFinder;
 import org.bukkit.ChatColor;
 import org.bukkit.Location;
 import org.bukkit.command.CommandSender;
@@ -50,7 +51,7 @@ public class SpawnCommand extends MultiverseCommand {
                 sender.sendMessage("You don't have permission to teleport another player to spawn. (multiverse.core.spawn.other)");
                 return;
             }
-            Player target = this.plugin.getServer().getPlayerExact(args.get(0));
+            Player target = PlayerFinder.get(args.get(0), sender);
             if (target != null) {
                 target.sendMessage("Teleporting to this world's spawn...");
                 spawnAccurately(target);

src/main/java/com/onarandombox/MultiverseCore/commands/TeleportCommand.java

@@ -18,6 +18,7 @@ import com.onarandombox.MultiverseCore.destination.WorldDestination;
 import com.onarandombox.MultiverseCore.enums.TeleportResult;
 import com.onarandombox.MultiverseCore.event.MVTeleportEvent;
 import com.onarandombox.MultiverseCore.api.SafeTTeleporter;
+import com.onarandombox.MultiverseCore.utils.PlayerFinder;
 import org.bukkit.ChatColor;
 import org.bukkit.Location;
 import org.bukkit.World;
@@ -28,13 +29,12 @@ import org.bukkit.permissions.PermissionDefault;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.logging.Level;
 
 /**
  * Used to teleport players.
  */
 public class TeleportCommand extends MultiverseCommand {
-    private final SafeTTeleporter playerTeleporter;
+    private SafeTTeleporter playerTeleporter;
 
     public TeleportCommand(MultiverseCore plugin) {
         super(plugin);
@@ -59,7 +59,7 @@ public class TeleportCommand extends MultiverseCommand {
         String destinationName;
 
         if (args.size() == 2) {
-            teleportee = this.plugin.getServer().getPlayerExact(args.get(0));
+            teleportee = PlayerFinder.get(args.get(0), sender);
             if (teleportee == null) {
                 this.messaging.sendMessage(sender, String.format("Sorry, I couldn't find player: %s%s",
                         ChatColor.GOLD, args.get(0)), false);
@@ -75,22 +75,9 @@ public class TeleportCommand extends MultiverseCommand {
             }
             teleportee = (Player) sender;
         }
-        // Special case for cannons:
-        if (destinationName.matches("(?i)cannon-[\\d]+(\\.[\\d]+)?")) {
-            String[] cannonSpeed = destinationName.split("-");
-            try {
-                double speed = Double.parseDouble(cannonSpeed[1]);
-                destinationName = "ca:" + teleportee.getWorld().getName() + ":" + teleportee.getLocation().getX()
-                        + "," + teleportee.getLocation().getY() + "," + teleportee.getLocation().getZ() + ":"
-                        + teleportee.getLocation().getPitch() + ":" + teleportee.getLocation().getYaw() + ":" + speed;
-            } catch (Exception e) {
-                destinationName = "i:invalid";
-            }
 
-        }
         DestinationFactory df = this.plugin.getDestFactory();
-        MVDestination d = df.getDestination(destinationName);
-
+        MVDestination d = df.getPlayerAwareDestination(teleportee, destinationName);
 
         MVTeleportEvent teleportEvent = new MVTeleportEvent(d, teleportee, teleporter, true);
         this.plugin.getServer().getPluginManager().callEvent(teleportEvent);

src/main/java/com/onarandombox/MultiverseCore/commands/VersionCommand.java

@@ -64,6 +64,7 @@ public class VersionCommand extends MultiverseCommand {
                 + "[Multiverse-Core]   teleportintercept: " + plugin.getMVConfig().getTeleportIntercept() + '\n'
                 + "[Multiverse-Core]   firstspawnoverride: " + plugin.getMVConfig().getFirstSpawnOverride() + '\n'
                 + "[Multiverse-Core]   displaypermerrors: " + plugin.getMVConfig().getDisplayPermErrors() + '\n'
+                + "[Multiverse-Core]   enablebuscript: " + plugin.getMVConfig().getEnableBuscript() + '\n'
                 + "[Multiverse-Core]   globaldebug: " + plugin.getMVConfig().getGlobalDebug() + '\n'
                 + "[Multiverse-Core]   silentstart: " + plugin.getMVConfig().getSilentStart() + '\n'
                 + "[Multiverse-Core]   messagecooldown: " + plugin.getMessaging().getCooldown() + '\n'

src/main/java/com/onarandombox/MultiverseCore/commands/WhoCommand.java

@@ -23,7 +23,8 @@ import java.util.List;
  * States who is in what world.
  */
 public class WhoCommand extends MultiverseCommand {
-    private final MVWorldManager worldManager;
+
+    private MVWorldManager worldManager;
 
     public WhoCommand(MultiverseCore plugin) {
         super(plugin);

src/main/java/com/onarandombox/MultiverseCore/configuration/EntryFee.java

@@ -22,6 +22,8 @@ public class EntryFee extends SerializationConfig {
     @Nullable
     private Material currency;
 
+    private final Material DISABLED_MATERIAL = Material.AIR;
+
     public EntryFee() {
         super();
     }
@@ -51,6 +53,9 @@ public class EntryFee extends SerializationConfig {
      */
     @Nullable
     public Material getCurrency() {
+        if (currency == null || currency.equals(DISABLED_MATERIAL)) {
+            return null;
+        }
         return currency;
     }
 

src/main/java/com/onarandombox/MultiverseCore/destination/DestinationFactory.java

@@ -11,16 +11,27 @@ import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MVDestination;
 import com.onarandombox.MultiverseCore.commands.TeleportCommand;
 import com.onarandombox.MultiverseCore.utils.PermissionTools;
+import com.onarandombox.MultiverseCore.utils.PlayerFinder;
 import com.pneumaticraft.commandhandler.Command;
+import org.bukkit.Bukkit;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
 import org.bukkit.permissions.Permission;
 import org.bukkit.permissions.PermissionDefault;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.regex.Pattern;
 
 /** A factory class that will create destinations from specific strings. */
 public class DestinationFactory {
+
+    private static final Pattern CANNON_PATTERN = Pattern.compile("(?i)cannon-[\\d]+(\\.[\\d]+)?");
+
     private MultiverseCore plugin;
     private Map<String, Class<? extends MVDestination>> destList;
     private Command teleportCommand;
@@ -36,6 +47,59 @@ public class DestinationFactory {
         }
     }
 
+    /**
+     * Parse a destination that has relation to sender, such as a cannon or player destination.
+     *
+     * @param teleportee        The player that is going to be teleported.
+     * @param destinationName   The destination to parse.
+     * @return A non-null MVDestination
+     */
+    @NotNull
+    public MVDestination getPlayerAwareDestination(@NotNull Player teleportee,
+                                                   @NotNull String destinationName) {
+
+        // Prioritise world, in the event that a world is named after a player online.
+        if (Bukkit.getWorld(destinationName) != null) {
+            return getDestination(destinationName);
+        }
+
+        Player targetPlayer = PlayerFinder.get(destinationName, teleportee);
+        if (targetPlayer != null) {
+            return getDestination("pl:" + targetPlayer.getName());
+        }
+
+        if (CANNON_PATTERN.matcher(destinationName).matches()) {
+            return getDestination(parseCannonDest(teleportee, destinationName));
+        }
+
+        return getDestination(destinationName);
+    }
+
+    /**
+     * Parses a cannon destination.
+     *
+     * @param teleportee        The player that is going to be teleported.
+     * @param destinationName   The destination to parse.
+     * @return A destination string.
+     */
+    @NotNull
+    private String parseCannonDest(@NotNull Player teleportee,
+                                   @NotNull String destinationName) {
+
+        String[] cannonSpeed = destinationName.split("-");
+        try {
+            double speed = Double.parseDouble(cannonSpeed[1]);
+            destinationName = "ca:" + teleportee.getWorld().getName() + ":" + teleportee.getLocation().getX()
+                    + "," + teleportee.getLocation().getY() + "," + teleportee.getLocation().getZ() + ":"
+                    + teleportee.getLocation().getPitch() + ":" + teleportee.getLocation().getYaw() + ":" + speed;
+        }
+        catch (Exception e) {
+            destinationName = "i:invalid";
+        }
+
+        return destinationName;
+    }
+
     /**
      * Gets a new destination from a string.
      * Returns a new InvalidDestination if the string could not be parsed.
@@ -101,4 +165,8 @@ public class DestinationFactory {
         this.teleportCommand.addAdditonalPermission(other);
         return true;
     }
+    
+    public Collection<String> getRegisteredIdentifiers() {
+        return this.destList.keySet();
+    }
 }

src/main/java/com/onarandombox/MultiverseCore/enums/RespawnType.java

@@ -0,0 +1,7 @@
+package com.onarandombox.MultiverseCore.enums;
+
+public enum RespawnType {
+    BED,
+    ANCHOR,
+    OTHER
+}

src/main/java/com/onarandombox/MultiverseCore/event/MVConfigReloadEvent.java

@@ -16,7 +16,7 @@ import java.util.List;
  * Called when the Multiverse-config should be reloaded.
  */
 public class MVConfigReloadEvent extends Event {
-    private final List<String> configsLoaded;
+    private List<String> configsLoaded;
 
     public MVConfigReloadEvent(List<String> configsLoaded) {
         this.configsLoaded = configsLoaded;

src/main/java/com/onarandombox/MultiverseCore/event/MVPlayerTouchedPortalEvent.java

@@ -17,8 +17,8 @@ import org.bukkit.event.HandlerList;
  * This event is thrown when a portal is touched.
  */
 public class MVPlayerTouchedPortalEvent extends Event implements Cancellable {
-    private final Player p;
-    private final Location l;
+    private Player p;
+    private Location l;
     private boolean isCancelled;
     private boolean canUse = true;
 

src/main/java/com/onarandombox/MultiverseCore/event/MVRespawnEvent.java

@@ -16,9 +16,10 @@ import org.bukkit.event.HandlerList;
  * Called when a player is respawning.
  */
 public class MVRespawnEvent extends Event {
-    private final Player player;
-    private final String respawnMethod;
+    private Player player;
     private Location location;
+    private String respawnMethod;
+
 
     public MVRespawnEvent(Location spawningAt, Player p, String respawnMethod) {
         this.player = p;

src/main/java/com/onarandombox/MultiverseCore/event/MVTeleportEvent.java

@@ -21,10 +21,10 @@ import org.bukkit.event.HandlerList;
  * Event that gets called when a player use the /mvtp command.
  */
 public class MVTeleportEvent extends Event implements Cancellable {
-    private final Player teleportee;
-    private final CommandSender teleporter;
-    private final MVDestination dest;
-    private final boolean useSafeTeleport;
+    private Player teleportee;
+    private CommandSender teleporter;
+    private MVDestination dest;
+    private boolean useSafeTeleport;
     private boolean isCancelled;
 
     public MVTeleportEvent(MVDestination dest, Player teleportee, CommandSender teleporter, boolean safeTeleport) {

src/main/java/com/onarandombox/MultiverseCore/event/MVWorldPropertyChangeEvent.java

@@ -24,11 +24,11 @@ import org.bukkit.event.HandlerList;
  * @param <T> The type of the property that was set.
  */
 public class MVWorldPropertyChangeEvent<T> extends Event implements Cancellable {
-    private final MultiverseWorld world;
-    private final CommandSender changer;
-    private final String name;
-    private T value;
+    private MultiverseWorld world;
+    private CommandSender changer;
     private boolean isCancelled = false;
+    private String name;
+    private T value;
 
     public MVWorldPropertyChangeEvent(MultiverseWorld world, CommandSender changer, String name, T value) {
         this.world = world;

src/main/java/com/onarandombox/MultiverseCore/listeners/MVEntityListener.java

@@ -28,8 +28,8 @@ import java.util.logging.Level;
  * Multiverse's Entity {@link Listener}.
  */
 public class MVEntityListener implements Listener {
-    private final MultiverseCore plugin;
-    private final MVWorldManager worldManager;
+    private MultiverseCore plugin;
+    private MVWorldManager worldManager;
 
     public MVEntityListener(MultiverseCore plugin) {
         this.plugin = plugin;

src/main/java/com/onarandombox/MultiverseCore/listeners/MVPlayerListener.java

@@ -15,7 +15,9 @@ import com.dumptruckman.minecraft.util.Logging;
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MVWorldManager;
 import com.onarandombox.MultiverseCore.api.MultiverseWorld;
+import com.onarandombox.MultiverseCore.enums.RespawnType;
 import com.onarandombox.MultiverseCore.event.MVRespawnEvent;
+import com.onarandombox.MultiverseCore.utils.CompatibilityLayer;
 import com.onarandombox.MultiverseCore.utils.PermissionTools;
 import org.bukkit.GameMode;
 import org.bukkit.Location;
@@ -69,9 +71,16 @@ public class MVPlayerListener implements Listener {
             return;
         }
 
+        RespawnType respawnType = RespawnType.OTHER;
+        if (event.isBedSpawn()) {
+            respawnType = RespawnType.BED;
+        }
+        if (CompatibilityLayer.isAnchorSpawn(event)) {
+            respawnType = RespawnType.ANCHOR;
+        }
 
-        if (mvWorld.getBedRespawn() && event.isBedSpawn()) {
-            Logging.fine("Spawning " + event.getPlayer().getName() + " at their bed");
+        if (mvWorld.getBedRespawn() && (respawnType == RespawnType.BED || respawnType == RespawnType.ANCHOR)) {
+            Logging.fine("Spawning %s at their %s", event.getPlayer().getName(), respawnType);
             return;
         }
 

src/main/java/com/onarandombox/MultiverseCore/listeners/MVPortalListener.java

@@ -26,7 +26,7 @@ import java.util.logging.Level;
  */
 public class MVPortalListener implements Listener {
 
-    private final MultiverseCore plugin;
+    private MultiverseCore plugin;
 
     public MVPortalListener(MultiverseCore core) {
         this.plugin = core;

src/main/java/com/onarandombox/MultiverseCore/listeners/MVWeatherListener.java

@@ -18,7 +18,7 @@ import org.bukkit.event.weather.WeatherChangeEvent;
  * Multiverse's Weather {@link Listener}.
  */
 public class MVWeatherListener implements Listener {
-    private final MultiverseCore plugin;
+    private MultiverseCore plugin;
 
     public MVWeatherListener(MultiverseCore plugin) {
         this.plugin = plugin;

src/main/java/com/onarandombox/MultiverseCore/listeners/MVWorldInitListener.java

@@ -14,7 +14,7 @@ import org.bukkit.event.world.WorldInitEvent;
 
 public class MVWorldInitListener implements Listener {
 
-    private final MultiverseCore plugin;
+    MultiverseCore plugin;
 
     public MVWorldInitListener(MultiverseCore plugin) {
         this.plugin = plugin;

src/main/java/com/onarandombox/MultiverseCore/listeners/MVWorldListener.java

@@ -20,8 +20,8 @@ import org.bukkit.event.world.WorldUnloadEvent;
  * Multiverse's World {@link Listener}.
  */
 public class MVWorldListener implements Listener {
-    private final MultiverseCore plugin;
-    private final MVWorldManager worldManager;
+    private MultiverseCore plugin;
+    private MVWorldManager worldManager;
 
     public MVWorldListener(MultiverseCore plugin) {
         this.plugin = plugin;

src/main/java/com/onarandombox/MultiverseCore/utils/CompatibilityLayer.java

@@ -0,0 +1,46 @@
+package com.onarandombox.MultiverseCore.utils;
+
+import com.dumptruckman.minecraft.util.Logging;
+import org.bukkit.Bukkit;
+import org.bukkit.event.player.PlayerRespawnEvent;
+
+import java.lang.reflect.Method;
+
+/**
+ * A utility class to enable version specific minecraft features.
+ */
+public class CompatibilityLayer {
+
+    private static Method checkAnchorSpawn;
+
+    /**
+     * Initialise the reflection methods.
+     */
+    public static void init() {
+        try {
+            checkAnchorSpawn = PlayerRespawnEvent.class.getDeclaredMethod("isAnchorSpawn");
+        } catch (NoSuchMethodException e) {
+            Logging.fine("%s does not support respawn anchors.", Bukkit.getVersion());
+        }
+    }
+
+    /**
+     * Check if the respawn point is of respawn anchor type.
+     * Introduced in minecraft 1.16
+     *
+     * @param event A player respawn event.
+     * @return If the respawn location is an anchor point.
+     */
+    public static boolean isAnchorSpawn(PlayerRespawnEvent event) {
+        if (checkAnchorSpawn == null) {
+            return false;
+        }
+        try {
+            return (boolean) checkAnchorSpawn.invoke(event);
+        } catch (Exception e) {
+            Logging.warning("Error checking for: %s", checkAnchorSpawn);
+            e.printStackTrace();
+        }
+        return false;
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/utils/PlayerFinder.java

@@ -0,0 +1,176 @@
+package com.onarandombox.MultiverseCore.utils;
+
+import com.dumptruckman.minecraft.util.Logging;
+import org.bukkit.Bukkit;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+/**
+ * Helper class to get {@link Player} from name, UUID or Selectors.
+ */
+public class PlayerFinder {
+
+    private static final Pattern UUID_REGEX = Pattern.compile("[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}");
+    private static final Pattern COMMA_SPLIT = Pattern.compile(",");
+
+    /**
+     * Get a {@link Player} based on an identifier of name UUID or selector.
+     *
+     * @param playerIdentifier  An identifier of name UUID or selector.
+     * @param sender            Target sender for selector.
+     * @return The player if found, else null.
+     */
+    @Nullable
+    public static Player get(@NotNull String playerIdentifier,
+                             @NotNull CommandSender sender) {
+
+        Player targetPlayer = getByName(playerIdentifier);
+        if (targetPlayer != null) {
+            return targetPlayer;
+        }
+        targetPlayer = getByUuid(playerIdentifier);
+        if (targetPlayer != null) {
+            return targetPlayer;
+        }
+        return getBySelector(playerIdentifier, sender);
+    }
+
+    /**
+     * Get multiple {@link Player} based on many identifiers of name UUID or selector.
+     *
+     * @param playerIdentifiers An identifier of multiple names, UUIDs or selectors, separated by comma.
+     * @param sender            Target sender for selector.
+     * @return A list of all the {@link Player} found.
+     */
+    @Nullable
+    public static List<Player> getMulti(@NotNull String playerIdentifiers,
+                                        @NotNull CommandSender sender) {
+
+        String[] playerIdentifierArray = COMMA_SPLIT.split(playerIdentifiers);
+        if (playerIdentifierArray == null || playerIdentifierArray.length == 0) {
+            return null;
+        }
+
+        List<Player> playerResults = new ArrayList<>();
+        for (String playerIdentifier : playerIdentifierArray) {
+            Player targetPlayer = getByName(playerIdentifier);
+            if (targetPlayer != null) {
+                playerResults.add(targetPlayer);
+                continue;
+            }
+            targetPlayer = getByUuid(playerIdentifier);
+            if (targetPlayer != null) {
+                playerResults.add(targetPlayer);
+                continue;
+            }
+            List<Player> targetPlayers = getMultiBySelector(playerIdentifier, sender);
+            if (targetPlayers != null) {
+                playerResults.addAll(targetPlayers);
+            }
+        }
+        return playerResults;
+    }
+
+    /**
+     * Get a {@link Player} based on player name.
+     *
+     * @param playerName    Name of a {@link Player}.
+     * @return The player if found, else null.
+     */
+    @Nullable
+    public static Player getByName(@NotNull String playerName) {
+        return Bukkit.getPlayerExact(playerName);
+    }
+
+    /**
+     * Get a {@link Player} based on player UUID.
+     *
+     * @param playerUuid    UUID of a player.
+     * @return The player if found, else null.
+     */
+    @Nullable
+    public static Player getByUuid(@NotNull String playerUuid) {
+        if (!UUID_REGEX.matcher(playerUuid).matches()) {
+            return null;
+        }
+        UUID uuid;
+        try {
+            uuid = UUID.fromString(playerUuid);
+        } catch (Exception e) {
+            return null;
+        }
+        return getByUuid(uuid);
+    }
+
+    /**
+     * Get a {@link Player} based on playerUUID.
+     *
+     * @param playerUuid    UUID of a player.
+     * @return The player if found, else null.
+     */
+    @Nullable
+    public static Player getByUuid(@NotNull UUID playerUuid) {
+        return Bukkit.getPlayer(playerUuid);
+    }
+
+    /**
+     * Get a {@link Player} based on vanilla selectors.
+     * https://minecraft.gamepedia.com/Commands#Target_selectors
+     *
+     * @param playerSelector    A target selector, usually starts with an '@'.
+     * @param sender            Target sender for selector.
+     * @return The player if only one found, else null.
+     */
+    @Nullable
+    public static Player getBySelector(@NotNull String playerSelector,
+                                       @NotNull CommandSender sender) {
+
+        List<Player> matchedPlayers = getMultiBySelector(playerSelector, sender);
+        if (matchedPlayers == null || matchedPlayers.isEmpty()) {
+            Logging.warning("No player found with selector '%s' for %s.", playerSelector, sender.getName());
+            return null;
+        }
+        if (matchedPlayers.size() > 1) {
+            Logging.warning("Ambiguous selector result '%s' for %s (more than one player matched) - %s",
+                    playerSelector, sender.getName(), matchedPlayers.toString());
+            return null;
+        }
+        return matchedPlayers.get(0);
+    }
+
+    /**
+     * Get multiple {@link Player} based on selector.
+     * https://minecraft.gamepedia.com/Commands#Target_selectors
+     *
+     * @param playerSelector    A target selector, usually starts with an '@'.
+     * @param sender            Target sender for selector.
+     * @return A list of all the {@link Player} found.
+     */
+    @Nullable
+    public static List<Player> getMultiBySelector(@NotNull String playerSelector,
+                                                  @NotNull CommandSender sender) {
+
+        if (playerSelector.charAt(0) != '@') {
+            return null;
+        }
+        try {
+            return Bukkit.selectEntities(sender, playerSelector).stream()
+                    .filter(e -> e instanceof Player)
+                    .map(e -> ((Player) e))
+                    .collect(Collectors.toList());
+        } catch (IllegalArgumentException e) {
+            Logging.warning("An error occurred while parsing selector '%s' for %s. Is it is the correct format?",
+                    playerSelector, sender.getName());
+            e.printStackTrace();
+            return null;
+        }
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/utils/ReflectHelper.java

@@ -0,0 +1,140 @@
+package com.onarandombox.MultiverseCore.utils;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+/**
+ * Utility class used to help in doing various reflection actions.
+ */
+public class ReflectHelper {
+
+    /**
+     * Try to get the {@link Class} based on its classpath.
+     *
+     * @param classPath The target classpath.
+     * @return A {@link Class} if found, else null.
+     */
+    @Nullable
+    public static Class<?> getClass(String classPath) {
+        try {
+            return Class.forName(classPath);
+        } catch (ClassNotFoundException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Check if the {@link Class} for a give classpath is present/valid.
+     *
+     * @param classPath Target classpath.
+     * @return True if class path is a valid class, else false.
+     */
+    public static boolean hasClass(String classPath) {
+        return getClass(classPath) != null;
+    }
+
+    /**
+     * Try to get a {@link Method} from a given class.
+     *
+     * @param clazz             The class to search the method on.
+     * @param methodName        Name of the method to get.
+     * @param parameterTypes    Parameters present for that method.
+     * @param <C>               The class type.
+     * @return A {@link Method} if found, else null.
+     */
+    @Nullable
+    public static <C> Method getMethod(Class<C> clazz, String methodName, Class<?>... parameterTypes) {
+        try {
+            Method method = clazz.getDeclaredMethod(methodName, parameterTypes);
+            method.setAccessible(true);
+            return method;
+        } catch (NoSuchMethodException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Try to get a {@link Method} from a given class.
+     *
+     * @param classInstance     Instance of the class to search the method on.
+     * @param methodName        Name of the method to get.
+     * @param parameterTypes    Parameters present for that method.
+     * @param <C>               The class type.
+     * @return A {@link Method} if found, else null.
+     */
+    @Nullable
+    public static <C> Method getMethod(C classInstance, String methodName, Class<?>... parameterTypes) {
+        return getMethod(classInstance.getClass(), methodName, parameterTypes);
+    }
+
+    /**
+     * Calls a {@link Method}.
+     *
+     * @param classInstance Instance of the class responsible for the method.
+     * @param method        The method to call.
+     * @param parameters    Parameters needed when calling the method.
+     * @param <C>           The class type.
+     * @param <R>           The return type.
+     * @return Return value of the method call if any, else null.
+     */
+    @Nullable
+    public static <C, R> R invokeMethod(C classInstance, Method method, Object...parameters) {
+        try {
+            return (R) method.invoke(classInstance, parameters);
+        } catch (Exception e) {
+            return null;
+        }
+    }
+
+    /**
+     * Try to get a {@link Field} from a given class.
+     *
+     * @param clazz     The class to search the field on.
+     * @param fieldName Name of the field to get.
+     * @param <C>       The class type.
+     * @return A {@link Field} if found, else null.
+     */
+    @Nullable
+    public static <C> Field getField(Class<C> clazz, String fieldName) {
+        try {
+            Field field = clazz.getDeclaredField(fieldName);
+            field.setAccessible(true);
+            return field;
+        } catch (NoSuchFieldException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Try to get a {@link Field} from a given class.
+     *
+     * @param classInstance Instance of the class to search the field on.
+     * @param fieldName     Name of the field to get.
+     * @param <C>           The class type.
+     * @return A {@link Field} if found, else null.
+     */
+    @Nullable
+    public static <C> Field getField(C classInstance, String fieldName) {
+        return getField(classInstance.getClass(), fieldName);
+    }
+
+    /**
+     * Gets the value of an {@link Field} from an instance of the class responsible.
+     *
+     * @param classInstance Instance of the class to get the field value from.
+     * @param field         The field to get value from.
+     * @param <C>           The class type.
+     * @param <V>           The field value type.
+     * @return The field value if any, else null.
+     */
+    @Nullable
+    public static <C, V> V getFieldValue(C classInstance, Field field)  {
+        try {
+            return (V) field.get(classInstance);
+        } catch (IllegalAccessException e) {
+            return null;
+        }
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/utils/SimpleLocationManipulation.java

@@ -40,6 +40,15 @@ public class SimpleLocationManipulation implements LocationManipulation {
         orientationInts.put("w", 90);
         orientationInts.put("nw", 135);
 
+        orientationInts.put("north", 180);
+        orientationInts.put("northeast", 225);
+        orientationInts.put("east", 270);
+        orientationInts.put("southeast", 315);
+        orientationInts.put("south", 0);
+        orientationInts.put("southwest", 45);
+        orientationInts.put("west", 90);
+        orientationInts.put("northwest", 135);
+
         // "freeze" the map:
         ORIENTATION_INTS = Collections.unmodifiableMap(orientationInts);
         // END CHECKSTYLE-SUPPRESSION: MagicNumberCheck

src/main/java/com/onarandombox/MultiverseCore/utils/WorldManager.java

@@ -36,19 +36,20 @@ import java.io.File;
 import java.io.FilenameFilter;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
 import java.util.Set;
 import java.util.Stack;
-import java.util.Arrays;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.logging.Level;
-import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 /**
  * Public facing API to add/remove Multiverse worlds.
@@ -59,6 +60,7 @@ public class WorldManager implements MVWorldManager {
     private final WorldPurger worldPurger;
     private final Map<String, MultiverseWorld> worlds;
     private Map<String, WorldProperties> worldsFromTheConfig;
+    private Set<String> defaultWorldNames;
     private FileConfiguration configWorlds = null;
     private Map<String, String> defaultGens;
     private String firstSpawn;
@@ -130,7 +132,7 @@ public class WorldManager implements MVWorldManager {
         }
 
         // Check for valid world name
-        if (!(isValidWorldName(oldName) && isValidWorldName(newName))) {
+        if (!(WorldNameChecker.isValidWorldName(oldName) && WorldNameChecker.isValidWorldName(oldName))) {
             return false;
         }
 
@@ -238,7 +240,9 @@ public class WorldManager implements MVWorldManager {
             return false;
         }
 
-        if (!isValidWorldName(name)) {
+        if (!WorldNameChecker.isValidWorldName(name)) {
+            Logging.warning("Invalid world name '" + name + "'");
+            Logging.warning("World name should not contain spaces or special characters!");
             return false;
         }
 
@@ -381,6 +385,11 @@ public class WorldManager implements MVWorldManager {
      */
     @Override
     public boolean unloadWorld(String name, boolean unloadBukkit) {
+        if (this.isDefaultWorld(name)) {
+            Logging.warning("You cannot unload the default worlds.");
+            Logging.warning("Default worlds on your server are: %s", this.defaultWorldNames);
+            return false;
+        }
         if (this.worlds.containsKey(name)) {
             this.worldsFromTheConfig.get(name).cacheVirtualProperties();
             if (unloadBukkit && this.unloadWorldFromBukkit(name, true)) {
@@ -424,21 +433,6 @@ public class WorldManager implements MVWorldManager {
         }
     }
 
-    /**
-     * Check if the world name is allowed
-     *
-     * @param name   Name of the world
-     * @return True if the world world name is valid based on regex
-     */
-    private boolean isValidWorldName(String name) {
-        if (!worldNamePattern.matcher(name).matches()) {
-            Logging.warning("Invalid world name '" + name + "'");
-            Logging.warning("World name should not contain spaces or special characters!");
-            return false;
-        }
-        return true;
-    }
-
     private void brokenWorld(String name) {
         Logging.severe("The world '" + name + "' could NOT be loaded because it contains errors and is probably corrupt!");
         Logging.severe("Try using Minecraft Region Fixer to repair your world! '" + name + "'");
@@ -630,6 +624,14 @@ public class WorldManager implements MVWorldManager {
      */
     @Override
     public MultiverseWorld getMVWorld(String name) {
+        return this.getMVWorld(name, true);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public MultiverseWorld getMVWorld(String name, boolean checkAliases) {
         if (name == null) {
             return null;
         }
@@ -637,7 +639,7 @@ public class WorldManager implements MVWorldManager {
         if (world != null) {
             return world;
         }
-        return this.getMVWorldByAlias(name);
+        return (checkAliases) ? this.getMVWorldByAlias(name) : null;
     }
 
     /**
@@ -646,7 +648,7 @@ public class WorldManager implements MVWorldManager {
     @Override
     public MultiverseWorld getMVWorld(World world) {
         if (world != null) {
-            return this.getMVWorld(world.getName());
+            return this.getMVWorld(world.getName(), false);
         }
         return null;
     }
@@ -671,7 +673,15 @@ public class WorldManager implements MVWorldManager {
      */
     @Override
     public boolean isMVWorld(final String name) {
-        return (this.worlds.containsKey(name) || isMVWorldAlias(name));
+        return this.isMVWorld(name, true);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean isMVWorld(final String name, boolean checkAliases) {
+        return this.worlds.containsKey(name) || (checkAliases && this.isMVWorldAlias(name));
     }
 
     /**
@@ -704,6 +714,7 @@ public class WorldManager implements MVWorldManager {
     public void loadDefaultWorlds() {
         this.ensureConfigIsPrepared();
         List<World> myWorlds = this.plugin.getServer().getWorlds();
+        this.defaultWorldNames = new HashSet<>(myWorlds.size());
         for (World w : myWorlds) {
             String name = w.getName();
             if (!worldsFromTheConfig.containsKey(name)) {
@@ -711,9 +722,15 @@ public class WorldManager implements MVWorldManager {
                 if (this.defaultGens.containsKey(name)) {
                     generator = this.defaultGens.get(name);
                 }
-                this.addWorld(name, w.getEnvironment(), String.valueOf(w.getSeed()), w.getWorldType(), w.canGenerateStructures(), generator);
+                if (!this.addWorld(name, w.getEnvironment(), String.valueOf(w.getSeed()), w.getWorldType(), w.canGenerateStructures(), generator)) {
+                    Logging.warning("Error loading default world '%s'!", w.getName());
+                    continue;
+                }
             }
+            this.defaultWorldNames.add(name);
         }
+        this.defaultWorldNames = Collections.unmodifiableSet(this.defaultWorldNames);
+        Logging.fine("Loaded default worlds: %s", this.defaultWorldNames);
     }
 
     private void ensureConfigIsPrepared() {
@@ -723,6 +740,21 @@ public class WorldManager implements MVWorldManager {
         }
     }
 
+    @Override
+    public boolean isDefaultWorld(MultiverseWorld world) {
+        return world != null && this.isDefaultWorld(world.getName());
+    }
+
+    @Override
+    public boolean isDefaultWorld(String worldName) {
+        return this.defaultWorldNames != null && this.defaultWorldNames.contains(worldName);
+    }
+
+    @Override
+    public Collection<String> getDefaultWorldNames() {
+        return this.defaultWorldNames;
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -953,4 +985,21 @@ public class WorldManager implements MVWorldManager {
 		}
 		return false;
 	}
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+	public Collection<String> getPotentialWorlds() {
+        File worldContainer = this.plugin.getServer().getWorldContainer();
+        if (worldContainer == null) {
+            return Collections.emptyList();
+        }
+        return Arrays.stream(worldContainer.listFiles())
+                .filter(File::isDirectory)
+                .filter(folder -> !this.isMVWorld(folder.getName(), false))
+                .filter(WorldNameChecker::isValidWorldFolder)
+                .map(File::getName)
+                .collect(Collectors.toList());
+    }
 }

src/main/java/com/onarandombox/MultiverseCore/utils/WorldNameChecker.java

@@ -0,0 +1,159 @@
+package com.onarandombox.MultiverseCore.utils;
+
+import org.bukkit.Bukkit;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.regex.Pattern;
+
+/**
+ * <p>Utility class in helping to check the status of a world name and it's associated world folder.</p>
+ *
+ * <p>Note this is for preliminary checks and better command output. A valid result will suggest but not
+ * 100% determine that a world name can be created, loaded or imported.</p>
+ */
+public class WorldNameChecker {
+
+    private static final Pattern WORLD_NAME_PATTERN = Pattern.compile("[a-zA-Z0-9/._-]+");
+    private static final Set<String> BLACKLIST_NAMES = Collections.unmodifiableSet(new HashSet<String>() {{
+        add("plugins");
+        add("logs");
+        add("cache");
+        add("crash-reports");
+    }});
+
+    /**
+     * Checks if a world name is valid.
+     *
+     * @param worldName The world name to check on.
+     * @return True if check result is valid, else false.
+     */
+    public static boolean isValidWorldName(@Nullable String worldName) {
+        return checkName(worldName) == NameStatus.VALID;
+    }
+
+    /**
+     * Checks the current validity status of a world name.
+     *
+     * @param worldName The world name to check on.
+     * @return The resulting name status.
+     */
+    @NotNull
+    public static NameStatus checkName(@Nullable String worldName) {
+        if (BLACKLIST_NAMES.contains(worldName)) {
+            return NameStatus.BLACKLISTED;
+        }
+        if (worldName == null || !WORLD_NAME_PATTERN.matcher(worldName).matches()) {
+            return NameStatus.INVALID_CHARS;
+        }
+        return NameStatus.VALID;
+    }
+
+    /**
+     * Checks if a world name has a valid world folder.
+     *
+     * @param worldName The world name to check on.
+     * @return True if check result is valid, else false.
+     */
+    public static boolean isValidWorldFolder(@Nullable String worldName) {
+        return checkFolder(worldName) == FolderStatus.VALID;
+    }
+
+    /**
+     * Checks if a world folder is valid.
+     *
+     * @param worldFolder   The world folder to check on.
+     * @return True if check result is valid, else false.
+     */
+    public static boolean isValidWorldFolder(@Nullable File worldFolder) {
+        return checkFolder(worldFolder) == FolderStatus.VALID;
+    }
+
+    /**
+     * Checks the current folder status for a world name.
+     *
+     * @param worldName The world name to check on.
+     * @return The resulting folder status.
+     */
+    @NotNull
+    public static FolderStatus checkFolder(@Nullable String worldName) {
+        if (worldName == null) {
+            return FolderStatus.DOES_NOT_EXIST;
+        }
+        File worldFolder = new File(Bukkit.getWorldContainer(), worldName);
+        return checkFolder(worldFolder);
+    }
+
+    /**
+     * Checks the current folder status.
+     *
+     * @param worldFolder   The world folder to check on.
+     * @return The resulting folder status.
+     */
+    @NotNull
+    public static FolderStatus checkFolder(@Nullable File worldFolder) {
+        if (worldFolder == null || !worldFolder.exists() || !worldFolder.isDirectory()) {
+            return FolderStatus.DOES_NOT_EXIST;
+        }
+        if (!folderHasDat(worldFolder)) {
+            return FolderStatus.NOT_A_WORLD;
+        }
+        return FolderStatus.VALID;
+    }
+
+    /**
+     * A very basic check to see if a folder has a level.dat file. If it does, we can safely assume
+     * it's a world folder.
+     *
+     * @param worldFolder   The File that may be a world.
+     * @return True if it looks like a world, else false.
+     */
+    private static boolean folderHasDat(@NotNull File worldFolder) {
+        File[] files = worldFolder.listFiles((file, name) -> name.toLowerCase().endsWith(".dat"));
+        return files != null && files.length > 0;
+    }
+
+    /**
+     * Result after checking validity of world name.
+     */
+    public enum NameStatus {
+        /**
+         * Name is valid.
+         */
+        VALID,
+
+        /**
+         * Name not valid as it contains invalid characters.
+         */
+        INVALID_CHARS,
+
+        /**
+         * Name not valid as it is deemed blacklisted.
+         */
+        BLACKLISTED
+    }
+
+    /**
+     * Result after checking validity of world folder.
+     */
+    public enum FolderStatus {
+        /**
+         * Folder is valid.
+         */
+        VALID,
+
+        /**
+         * Folder exist, but contents in it doesnt look like a world.
+         */
+        NOT_A_WORLD,
+
+        /**
+         * Folder does not exist.
+         */
+        DOES_NOT_EXIST
+    }
+}

src/test/java/com/onarandombox/MultiverseCore/TestEntryFeeConversion.java

@@ -50,6 +50,10 @@ public class TestEntryFeeConversion {
         WorldProperties props = new WorldProperties(config);
         assertNull(props.entryfee.getCurrency());
 
+        entryFee.put("currency", 0);
+        props = new WorldProperties(config);
+        assertNull(props.entryfee.getCurrency());
+
         entryFee.put("currency", 1);
         props = new WorldProperties(config);
         assertEquals(Material.STONE, props.entryfee.getCurrency());

src/test/java/com/onarandombox/MultiverseCore/utils/TestInstanceCreator.java

@@ -214,11 +214,18 @@ public class TestInstanceCreator {
             serverfield.set(core, mockServer);
 
             // Set buscript
-            Buscript buscript = PowerMockito.spy(new Buscript(core));
+            Buscript buscript;
             Field buscriptfield = MultiverseCore.class.getDeclaredField("buscript");
             buscriptfield.setAccessible(true);
+
+            try {
+                buscript = PowerMockito.spy(new Buscript(core));
+                when(buscript.getPlugin()).thenReturn(core);
+            } catch (NullPointerException e) {
+                buscript = null;
+            }
+
             buscriptfield.set(core, buscript);
-            when(buscript.getPlugin()).thenReturn(core);
 
             // Set worldManager
             WorldManager wm = PowerMockito.spy(new WorldManager(core));