Improve world name/folder checking for create and import command.

Make use of the new WorldNameChecker class.

pom.xml

@@ -27,17 +27,13 @@
             <url>https://hub.spigotmc.org/nexus/content/groups/public/</url>
         </repository>
         <repository>
-            <id>vault-repo</id>
-            <url>http://nexus.hc.to/content/repositories/pub_releases</url>
+            <id>jitpack.io</id>
+            <url>https://jitpack.io</url>
         </repository>
         <repository>
             <id>minebench-repo</id>
             <url>https://repo.minebench.de/</url>
         </repository>
-        <repository>
-            <id>CodeMC</id>
-            <url>https://repo.codemc.org/repository/maven-public</url>
-        </repository>
     </repositories>
 
     <pluginRepositories>
@@ -223,6 +219,7 @@
                             <goal>shade</goal>
                         </goals>
                         <configuration>
+                            <minimizeJar>true</minimizeJar>
                             <relocations>
                                 <relocation>
                                     <pattern>me.main__.util</pattern>
@@ -305,7 +302,7 @@
         <!-- End of SerializationConfig Dependency -->
         <!-- Start of Economy Dependency -->
         <dependency>
-            <groupId>net.milkbowl.vault</groupId>
+            <groupId>com.github.MilkBowl</groupId>
             <artifactId>VaultAPI</artifactId>
             <version>1.7</version>
             <scope>provided</scope>
@@ -325,13 +322,7 @@
         <dependency>
             <groupId>org.bstats</groupId>
             <artifactId>bstats-bukkit</artifactId>
-            <version>1.8</version>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.bukkit</groupId>
-                    <artifactId>bukkit</artifactId>
-                </exclusion>
-            </exclusions>
+            <version>2.2.1</version>
         </dependency>
         <dependency>
             <groupId>com.dumptruckman.minecraft</groupId>

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

@@ -367,7 +367,9 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
                 // 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!");
+                Logging.warning("Buscript failed to load! The script command will be disabled! " +
+                        "If you would like not to see this message, " +
+                        "use `/mv conf enablebuscript false` to disable Buscript from loading.");
             }
         }
     }
@@ -1129,12 +1131,22 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
 
     /**
      * {@inheritDoc}
-     * @deprecated This is deprecated!
+     * @deprecated This is deprecated! Do not use!
      */
     @Override
     @Deprecated
     public Boolean regenWorld(String name, Boolean useNewSeed, Boolean randomSeed, String seed) {
-        return this.worldManager.regenWorld(name, useNewSeed, randomSeed, seed);
+        return this.worldManager.regenWorld(name, useNewSeed, randomSeed, seed, false);
+    }
+
+    /**
+     * {@inheritDoc}
+     * @deprecated This is deprecated! Do not use!
+     */
+    @Override
+    @Deprecated
+    public Boolean regenWorld(String name, Boolean useNewSeed, Boolean randomSeed, String seed, Boolean keepGameRules) {
+        return this.worldManager.regenWorld(name, useNewSeed, randomSeed, seed, keepGameRules);
     }
 
     /**

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

@@ -1,7 +1,5 @@
 package com.onarandombox.MultiverseCore;
 
-import java.util.Map;
-
 import com.dumptruckman.minecraft.util.Logging;
 import com.onarandombox.MultiverseCore.api.MultiverseCoreConfig;
 import com.onarandombox.MultiverseCore.event.MVDebugModeEvent;
@@ -10,6 +8,8 @@ import me.main__.util.SerializationConfig.Property;
 import me.main__.util.SerializationConfig.SerializationConfig;
 import org.bukkit.Bukkit;
 
+import java.util.Map;
+
 /**
  * Our configuration.
  */
@@ -77,6 +77,8 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
     private volatile boolean autopurge;
     @Property
     private volatile boolean idonotwanttodonate;
+    @Property
+    private volatile boolean allowunsafeworldname;
 
     public MultiverseCoreConfiguration() {
         super();
@@ -96,7 +98,7 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
         // BEGIN CHECKSTYLE-SUPPRESSION: MagicNumberCheck
         enforceaccess = false;
         useasyncchat = true;
-        prefixchat = true;
+        prefixchat = false;
         prefixchatformat = "[%world%]%chat%";
         teleportintercept = true;
         firstspawnoverride = true;
@@ -111,6 +113,7 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
         portalsearchradius = 128;
         autopurge = true;
         idonotwanttodonate = false;
+        allowunsafeworldname = false;
         // END CHECKSTYLE-SUPPRESSION: MagicNumberCheck
     }
 
@@ -382,4 +385,14 @@ public class MultiverseCoreConfiguration extends SerializationConfig implements
     public void setShowDonateMessage(boolean showDonateMessage) {
         this.idonotwanttodonate = !showDonateMessage;
     }
+
+    @Override
+    public boolean isAllowUnsafeWorldName() {
+        return allowunsafeworldname;
+    }
+
+    @Override
+    public void setAllowUnsafeWorldName(boolean allowUnsafeWorldName) {
+        this.allowunsafeworldname = allowUnsafeWorldName;
+    }
 }

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

@@ -126,20 +126,38 @@ public interface Core {
     AnchorManager getAnchorManager();
 
     /**
-     * Used by queued commands to regenerate a world on a delay.
+     * Previously used by queued commands to regenerate a world on a delay.
+     * Do not use api method for any other purpose.
      *
-     * @param name Name of the world to regenerate
-     * @param useNewSeed If a new seed should be used
-     * @param randomSeed IF the new seed should be random
-     * @param seed The seed of the world.
+     * @param name          Name of the world to regenerate
+     * @param useNewSeed    If a new seed should be used
+     * @param randomSeed    If the new seed should be random
+     * @param seed          The seed of the world.
      *
      * @return True if success, false if fail.
      *
-     * @deprecated Use {@link MVWorldManager#regenWorld(String, boolean, boolean, String)} instead.
+     * @deprecated Use {@link MVWorldManager#regenWorld(String, boolean, boolean, String, boolean)} instead.
      */
     @Deprecated
     Boolean regenWorld(String name, Boolean useNewSeed, Boolean randomSeed, String seed);
 
+    /**
+     * Used by queued commands to regenerate a world on a delay.
+     * Do not use api method for any other purpose.
+     *
+     * @param name          Name of the world to regenerate
+     * @param useNewSeed    If a new seed should be used
+     * @param randomSeed    If the new seed should be random
+     * @param seed          The seed of the world.
+     * @param keepGameRules If GameRules should be kept on world regen.
+     *
+     * @return True if success, false if fail.
+     *
+     * @deprecated Use {@link MVWorldManager#regenWorld(String, boolean, boolean, String, boolean)} instead.
+     */
+    @Deprecated
+    Boolean regenWorld(String name, Boolean useNewSeed, Boolean randomSeed, String seed, Boolean keepGameRules);
+
     /**
      * Decrements the number of plugins that have specifically hooked into core.
      */

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}.
      *
@@ -292,15 +313,28 @@ public interface MVWorldManager {
     /**
      * Regenerates a world.
      *
-     * @param name Name of the world to regenerate
-     * @param useNewSeed If a new seed should be used
-     * @param randomSeed IF the new seed should be random
-     * @param seed The seed of the world.
+     * @param name          Name of the world to regenerate
+     * @param useNewSeed    If a new seed should be used
+     * @param randomSeed    If the new seed should be random
+     * @param seed          The seed of the world.
      *
      * @return True if success, false if fail.
      */
     boolean regenWorld(String name, boolean useNewSeed, boolean randomSeed, String seed);
 
+    /**
+     * Regenerates a world.
+     *
+     * @param name          Name of the world to regenerate
+     * @param useNewSeed    If a new seed should be used
+     * @param randomSeed    If the new seed should be random
+     * @param seed          The seed of the world.
+     * @param keepGameRules If GameRules should be kept on world regen.
+     *
+     * @return True if success, false if fail.
+     */
+    boolean regenWorld(String name, boolean useNewSeed, boolean randomSeed, String seed, boolean keepGameRules);
+
     boolean isKeepingSpawnInMemory(World world);
     
     /**
@@ -314,4 +348,11 @@ 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

@@ -239,4 +239,8 @@ public interface MultiverseCoreConfig extends ConfigurationSerializable {
      * @param idonotwanttodonate True if donation/patreon messages should be shown.
      */
     void setShowDonateMessage(boolean idonotwanttodonate);
+
+    boolean isAllowUnsafeWorldName();
+
+    void setAllowUnsafeWorldName(boolean allowUnsafeWorldName);
 }

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/CreateCommand.java

@@ -9,6 +9,7 @@ package com.onarandombox.MultiverseCore.commands;
 
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MVWorldManager;
+import com.onarandombox.MultiverseCore.utils.WorldNameChecker;
 import com.pneumaticraft.commandhandler.CommandHandler;
 import org.bukkit.ChatColor;
 import org.bukkit.World.Environment;
@@ -17,7 +18,6 @@ import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
 import org.bukkit.permissions.PermissionDefault;
 
-import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -50,7 +50,6 @@ public class CreateCommand extends MultiverseCommand {
     @Override
     public void runCommand(CommandSender sender, List<String> args) {
         String worldName = args.get(0);
-        File worldFile = new File(this.plugin.getServer().getWorldContainer(), worldName);
         String env = args.get(1);
         String seed = CommandHandler.getFlag("-s", args);
         String generator = CommandHandler.getFlag("-g", args);
@@ -67,13 +66,19 @@ public class CreateCommand extends MultiverseCommand {
             }
         }
 
+		if(!this.plugin.getMVConfig().isAllowUnsafeWorldName() && !WorldNameChecker.isValidWorldName(worldName)) {
+			sender.sendMessage(ChatColor.RED + "Multiverse cannot create the world as the world name '"
+                    + worldName + "' contains spaces or invalid characters!");
+            return;
+		}
+
         if (this.worldManager.isMVWorld(worldName)) {
             sender.sendMessage(ChatColor.RED + "Multiverse cannot create " + ChatColor.GOLD + ChatColor.UNDERLINE
                     + "another" + ChatColor.RESET + ChatColor.RED + " world named " + worldName);
             return;
         }
 
-        if (worldFile.exists()) {
+        if (WorldNameChecker.checkFolder(worldName) != WorldNameChecker.FolderStatus.DOES_NOT_EXIST) {
             sender.sendMessage(ChatColor.RED + "A Folder/World already exists with this name!");
             sender.sendMessage(ChatColor.RED + "If you are confident it is a world you can import with /mvimport");
             return;
@@ -117,4 +122,4 @@ public class CreateCommand extends MultiverseCommand {
             Command.broadcastCommandMessage(sender, "FAILED.");
         }
     }
-}
+}

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;
@@ -17,9 +17,6 @@ import org.bukkit.command.Command;
 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;
 
@@ -45,68 +42,25 @@ 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;
-    }
-    
-    private String trimWorldName(String userInput) {
-        // Removes relative paths.
-        return userInput.replaceAll("^[./\\\\]+", "");
+
+        return worldList.toString();
     }
 
     @Override
     public void runCommand(CommandSender sender, List<String> args) {
-        String worldName = trimWorldName(args.get(0));
+        String worldName = 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);
@@ -121,6 +75,12 @@ public class ImportCommand extends MultiverseCommand {
             this.showHelp(sender);
             return;
         }
+		
+        if(!this.plugin.getMVConfig().isAllowUnsafeWorldName() && !WorldNameChecker.isValidWorldName(worldName)) {
+            sender.sendMessage(ChatColor.RED + "Multiverse cannot import the world as the world name '"
+                    + worldName + "' contains spaces or invalid characters!");
+            return;
+        }
 
         // Make sure we don't already know about this world.
         if (this.worldManager.isMVWorld(worldName)) {
@@ -129,7 +89,18 @@ public class ImportCommand extends MultiverseCommand {
             return;
         }
 
-        File worldFile = new File(this.plugin.getServer().getWorldContainer(), worldName);
+        switch (WorldNameChecker.checkFolder(worldName)) {
+            case DOES_NOT_EXIST:
+                sender.sendMessage(ChatColor.RED + "FAILED.");
+                sender.sendMessage(ChatColor.RED + "That world folder does not exist. These look like worlds to me:");
+                sender.sendMessage(this.getPotentialWorldStrings());
+                return;
+            case NOT_A_WORLD:
+                sender.sendMessage(ChatColor.RED + "FAILED.");
+                sender.sendMessage(String.format("%s'%s' does not appear to be a world. It is lacking a .dat file.",
+                        ChatColor.RED, worldName));
+                return;
+        }
 
         String generator = CommandHandler.getFlag("-g", args);
         boolean useSpawnAdjust = true;
@@ -147,25 +118,18 @@ public class ImportCommand extends MultiverseCommand {
             return;
         }
 
-        if (!worldFile.exists()) {
-            sender.sendMessage(ChatColor.RED + "FAILED.");
-            String worldList = this.getPotentialWorlds();
-            sender.sendMessage("That world folder does not exist. These look like worlds to me:");
-            sender.sendMessage(worldList);
-        } else if (!checkIfIsWorld(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));
-        } else if (env == null) {
+        if (env == null) {
             sender.sendMessage(ChatColor.RED + "FAILED.");
             sender.sendMessage("That world environment did not exist.");
             sender.sendMessage("For a list of available world types, type: " + ChatColor.AQUA + "/mvenv");
+            return;
+        }
+
+        Command.broadcastCommandMessage(sender, String.format("Starting import of world '%s'...", worldName));
+        if (this.worldManager.addWorld(worldName, environment, null, null, null, generator, useSpawnAdjust)) {
+            Command.broadcastCommandMessage(sender, ChatColor.GREEN + "Complete!");
         } else {
-            Command.broadcastCommandMessage(sender, String.format("Starting import of world '%s'...", worldName));
-            if (this.worldManager.addWorld(worldName, environment, null, null, null, generator, useSpawnAdjust))
-                Command.broadcastCommandMessage(sender, ChatColor.GREEN + "Complete!");
-            else
-                Command.broadcastCommandMessage(sender, ChatColor.RED + "Failed!");
+            Command.broadcastCommandMessage(sender, ChatColor.RED + "Failed!");
         }
     }
-}
+}

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

@@ -9,12 +9,12 @@ package com.onarandombox.MultiverseCore.commands;
 
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.commandtools.queue.QueuedCommand;
+import com.pneumaticraft.commandhandler.CommandHandler;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
 import org.bukkit.permissions.PermissionDefault;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -25,8 +25,8 @@ public class RegenCommand extends MultiverseCommand {
     public RegenCommand(MultiverseCore plugin) {
         super(plugin);
         this.setName("Regenerates a World");
-        this.setCommandUsage("/mv regen" + ChatColor.GREEN + " {WORLD}" + ChatColor.GOLD + " [-s [SEED]]");
-        this.setArgRange(1, 3);
+        this.setCommandUsage("/mv regen" + ChatColor.GREEN + " {WORLD}" + ChatColor.GOLD + " [-s [SEED]] [--keep-gamerules]");
+        this.setArgRange(1, 4);
         this.addKey("mvregen");
         this.addKey("mv regen");
         this.addCommandExample("You can use the -s with no args to get a new seed:");
@@ -43,10 +43,10 @@ public class RegenCommand extends MultiverseCommand {
         boolean useseed = (!(args.size() == 1));
         boolean randomseed = (args.size() == 2 && args.get(1).equalsIgnoreCase("-s"));
         String seed = (args.size() == 3) ? args.get(2) : "";
-
+        boolean keepGamerules = CommandHandler.hasFlag("--keep-gamerules", args);
         this.plugin.getCommandQueueManager().addToQueue(new QueuedCommand(
                 sender,
-                doWorldRegen(sender, worldName, useseed, randomseed, seed),
+                doWorldRegen(sender, worldName, useseed, randomseed, seed, keepGamerules),
                 String.format("Are you sure you want to regen '%s'? You cannot undo this action.", worldName)
         ));
     }
@@ -55,10 +55,11 @@ public class RegenCommand extends MultiverseCommand {
                                   @NotNull String worldName,
                                   boolean useSeed,
                                   boolean randomSeed,
-                                  @NotNull String seed) {
+                                  @NotNull String seed,
+                                  boolean keepGamerules) {
 
         return () -> {
-            if (this.plugin.getMVWorldManager().regenWorld(worldName, useSeed, randomSeed, seed)) {
+            if (this.plugin.getMVWorldManager().regenWorld(worldName, useSeed, randomSeed, seed, keepGamerules)) {
                 sender.sendMessage(ChatColor.GREEN + "World Regenerated!");
                 return;
             }

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

@@ -19,6 +19,7 @@ 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;
@@ -29,7 +30,6 @@ import org.bukkit.permissions.PermissionDefault;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.logging.Level;
 
 /**
  * Used to teleport players.
@@ -60,7 +60,7 @@ 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);
@@ -76,22 +76,9 @@ 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/destination/DestinationFactory.java

@@ -11,16 +11,29 @@ 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. */
+/**
+ * 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 +49,59 @@ 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 +167,13 @@ public class DestinationFactory {
         this.teleportCommand.addAdditonalPermission(other);
         return true;
     }
+
+    /**
+     * Gets all the {@link MVDestination} identifiers registered.
+     *
+     * @return A collection of destination identifiers.
+     */
+    public Collection<String> getRegisteredIdentifiers() {
+        return this.destList.keySet();
+    }
 }

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

@@ -11,6 +11,7 @@ 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.utils.CompatibilityLayer;
 import org.bukkit.World;
 import org.bukkit.entity.EntityType;
 import org.bukkit.entity.Player;
@@ -18,6 +19,7 @@ import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.entity.CreatureSpawnEvent;
 import org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason;
+import org.bukkit.event.entity.EntityPortalEvent;
 import org.bukkit.event.entity.EntityRegainHealthEvent;
 import org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason;
 import org.bukkit.event.entity.FoodLevelChangeEvent;
@@ -107,4 +109,17 @@ public class MVEntityListener implements Listener {
         event.setCancelled(this.plugin.getMVWorldManager().getTheWorldPurger().shouldWeKillThisCreature(mvworld, event.getEntity()));
     }
 
+    /**
+     * Handles portal search radius adjustment.
+     * @param event The Event that was fired.
+     */
+    @EventHandler
+    public void entityPortal(EntityPortalEvent event) {
+        if (event.isCancelled() || event.getTo() == null) {
+            return;
+        }
+        if (!this.plugin.getMVConfig().isUsingDefaultPortalSearch()) {
+            CompatibilityLayer.setPortalSearchRadius(event, this.plugin.getMVConfig().getPortalSearchRadius());
+        }
+    }
 }

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

@@ -7,10 +7,6 @@
 
 package com.onarandombox.MultiverseCore.listeners;
 
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.logging.Level;
-
 import com.dumptruckman.minecraft.util.Logging;
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MVWorldManager;
@@ -35,6 +31,9 @@ import org.bukkit.event.player.PlayerQuitEvent;
 import org.bukkit.event.player.PlayerRespawnEvent;
 import org.bukkit.event.player.PlayerTeleportEvent;
 
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
 /**
  * Multiverse's {@link Listener} for players.
  */
@@ -313,16 +312,8 @@ public class MVPlayerListener implements Listener {
                     + "' was allowed to go to '" + event.getTo().getWorld().getName()
                     + "' because enforceaccess is off.");
         }
-        if (!plugin.getMVConfig().isUsingDefaultPortalSearch()) {
-            try {
-                Class.forName("org.bukkit.TravelAgent");
-                if (event.getPortalTravelAgent() != null) {
-                    event.getPortalTravelAgent().setSearchRadius(plugin.getMVConfig().getPortalSearchRadius());
-                }
-            } catch (ClassNotFoundException ignore) {
-                Logging.fine("TravelAgent not available for PlayerPortalEvent for " + event.getPlayer().getName());
-            }
-
+        if (!this.plugin.getMVConfig().isUsingDefaultPortalSearch()) {
+            CompatibilityLayer.setPortalSearchRadius(event, this.plugin.getMVConfig().getPortalSearchRadius());
         }
     }
 

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

@@ -1,32 +1,35 @@
 package com.onarandombox.MultiverseCore.utils;
 
 import com.dumptruckman.minecraft.util.Logging;
-import org.bukkit.Bukkit;
+import org.bukkit.event.entity.EntityPortalEvent;
+import org.bukkit.event.player.PlayerPortalEvent;
 import org.bukkit.event.player.PlayerRespawnEvent;
 
 import java.lang.reflect.Method;
 
 /**
- * A utility class to enable version specific minecraft features.
+ * Utility class to enable version specific minecraft features.
  */
 public class CompatibilityLayer {
 
     private static Method checkAnchorSpawn;
+    private static boolean useTravelAgent;
+    private static Method playerPortalSearchRadius;
+    private static Method entityPortalSearchRadius;
 
     /**
-     * Initialise the reflection methods.
+     * Initialise the reflection class, methods and fields.
      */
     public static void init() {
-        try {
-            checkAnchorSpawn = PlayerRespawnEvent.class.getDeclaredMethod("isAnchorSpawn");
-        } catch (NoSuchMethodException e) {
-            Logging.fine("%s does not support respawn anchors.", Bukkit.getVersion());
-        }
+        checkAnchorSpawn = ReflectHelper.getMethod(PlayerRespawnEvent.class, "isAnchorSpawn");
+        useTravelAgent = ReflectHelper.hasClass("org.bukkit.TravelAgent");
+        playerPortalSearchRadius = ReflectHelper.getMethod(PlayerPortalEvent.class, "setSearchRadius", int.class);
+        entityPortalSearchRadius = ReflectHelper.getMethod(EntityPortalEvent.class, "setSearchRadius", int.class);
     }
 
     /**
-     * Check if the respawn point is of respawn anchor type.
-     * Introduced in minecraft 1.16
+     * <p>Check if the respawn point is of respawn anchor type.</p>
+     * <p>Introduced in minecraft 1.16</p>
      *
      * @param event A player respawn event.
      * @return If the respawn location is an anchor point.
@@ -35,12 +38,69 @@ public class CompatibilityLayer {
         if (checkAnchorSpawn == null) {
             return false;
         }
-        try {
-            return (boolean) checkAnchorSpawn.invoke(event);
-        } catch (Exception e) {
-            Logging.warning("Error checking for: %s", checkAnchorSpawn);
-            e.printStackTrace();
+        Boolean result = ReflectHelper.invokeMethod(event, checkAnchorSpawn);
+        if (result == null) {
+            Logging.warning("Unable to check if spawning at respawn anchor!");
+            return false;
         }
-        return false;
+        return result;
     }
-}
+
+    /**
+     * <p>Gets if Travel Agent is supported on the server's minecraft version.</p>
+     * <p>Removed in minecraft 1.14</p>
+     *
+     * @return True if Travel Agent is supported, else false.
+     */
+    public static boolean isUseTravelAgent() {
+        return useTravelAgent;
+    }
+
+    /**
+     * <p>Sets search radius for a PlayerPortalEvent.</p>
+     *
+     * <p>Use travel agent if available, else using new PlayerPortalEvent.setSearchRadius(int) method
+     * introduced in minecraft 1.15</p>
+     *
+     * @param event         A Player Portal Event.
+     * @param searchRadius  Target search radius to set to.
+     */
+    public static void setPortalSearchRadius(PlayerPortalEvent event, int searchRadius) {
+        if (useTravelAgent) {
+            event.getPortalTravelAgent().setSearchRadius(searchRadius);
+            event.useTravelAgent(true);
+            Logging.finer("Used travel agent to set player portal search radius.");
+            return;
+        }
+        if (playerPortalSearchRadius == null) {
+            Logging.warning("Unable to set player portal search radius!");
+            return;
+        }
+        ReflectHelper.invokeMethod(event, playerPortalSearchRadius, searchRadius);
+        Logging.finer("Used new method to set player portal search radius.");
+    }
+
+    /**
+     * <p>Sets search radius for a EntityPortalEvent.</p>
+     *
+     * <p>Use travel agent if available, else using new EntityPortalEvent.setSearchRadius(int) method
+     * introduced in minecraft 1.15</p>
+     *
+     * @param event         A Entity Portal Event.
+     * @param searchRadius  Target search radius to set to.
+     */
+    public static void setPortalSearchRadius(EntityPortalEvent event, int searchRadius) {
+        if (useTravelAgent) {
+            event.getPortalTravelAgent().setSearchRadius(searchRadius);
+            event.useTravelAgent(true);
+            Logging.finer("Used travel agent to set entity portal search radius.");
+            return;
+        }
+        if (entityPortalSearchRadius == null) {
+            Logging.warning("Unable to set entity portal search radius!");
+            return;
+        }
+        ReflectHelper.invokeMethod(event, entityPortalSearchRadius, searchRadius);
+        Logging.finer("Used new method to set entity portal search radius.");
+    }
+}

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.fine("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/WorldManager.java

@@ -18,6 +18,7 @@ import com.onarandombox.MultiverseCore.api.SafeTTeleporter;
 import com.onarandombox.MultiverseCore.api.WorldPurger;
 import com.onarandombox.MultiverseCore.event.MVWorldDeleteEvent;
 import org.bukkit.Bukkit;
+import org.bukkit.GameRule;
 import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.World.Environment;
@@ -36,26 +37,24 @@ 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.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.
  */
 public class WorldManager implements MVWorldManager {
     private final MultiverseCore plugin;
-    private final Pattern worldNamePattern = Pattern.compile("[a-zA-Z0-9/._-]+");
     private final WorldPurger worldPurger;
     private final Map<String, MultiverseWorld> worlds;
     private Map<String, WorldProperties> worldsFromTheConfig;
@@ -130,7 +129,11 @@ public class WorldManager implements MVWorldManager {
         }
 
         // Check for valid world name
-        if (!(isValidWorldName(oldName) && isValidWorldName(newName))) {
+        if (!this.plugin.getMVConfig().isAllowUnsafeWorldName() && !WorldNameChecker.isValidWorldName(newName)) {
+            Logging.warning("Unable to clone world as world name '" + newName + "' is invalid.");
+            Logging.warning("World name should not contain spaces or special characters!");
+            Logging.warning("Enable allowunsafeworldname to bypass the check if you are absolutely sure this world is valid.");
+            Logging.warning("However, MV is not response of any damage to your world if you enable this option.");
             return false;
         }
 
@@ -234,11 +237,12 @@ public class WorldManager implements MVWorldManager {
     @Override
     public boolean addWorld(String name, Environment env, String seedString, WorldType type, Boolean generateStructures,
                             String generator, boolean useSpawnAdjust) {
-        if (name.equalsIgnoreCase("plugins") || name.equalsIgnoreCase("logs")) {
-            return false;
-        }
 
-        if (!isValidWorldName(name)) {
+        if (!this.plugin.getMVConfig().isAllowUnsafeWorldName() && !WorldNameChecker.isValidWorldName(name)) {
+            Logging.warning("Unable to add world as world name '" + name + "' is invalid.");
+            Logging.warning("World name should not contain spaces or special characters!");
+            Logging.warning("Enable allowunsafeworldname to bypass the check if you are absolutely sure this world is valid.");
+            Logging.warning("However, MV is not response of any damage to your world if you enable this option.");
             return false;
         }
 
@@ -385,14 +389,14 @@ public class WorldManager implements MVWorldManager {
             this.worldsFromTheConfig.get(name).cacheVirtualProperties();
             if (unloadBukkit && this.unloadWorldFromBukkit(name, true)) {
                 this.worlds.remove(name);
-                Logging.info("World '%s' was unloaded from memory.", name);
+                Logging.info("World '%s' was unloaded from Bukkit.", name);
                 return true;
             } else if (!unloadBukkit){
                 this.worlds.remove(name);
-                Logging.info("World '%s' was unloaded from memory.", name);
+                Logging.info("World '%s' was unloaded from Multiverse.", name);
                 return true;
             } else {
-                Logging.warning("World '%s' could not be unloaded. Is it a default world?", name);
+                Logging.warning("World '%s' could not be unloaded from Bukkit. Is it a default world?", name);
             }
         } else if (this.plugin.getServer().getWorld(name) != null) {
             Logging.warning("Hmm Multiverse does not know about this world but it's loaded in memory.");
@@ -424,21 +428,6 @@ 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 +619,14 @@ 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 +634,7 @@ public class WorldManager implements MVWorldManager {
         if (world != null) {
             return world;
         }
-        return this.getMVWorldByAlias(name);
+        return (checkAliases) ? this.getMVWorldByAlias(name) : null;
     }
 
     /**
@@ -646,7 +643,7 @@ 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 +668,15 @@ 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));
     }
 
     /**
@@ -894,12 +899,23 @@ public class WorldManager implements MVWorldManager {
      */
     @Override
     public boolean regenWorld(String name, boolean useNewSeed, boolean randomSeed, String seed) {
+        return regenWorld(name, useNewSeed, randomSeed, seed, false);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean regenWorld(String name, boolean useNewSeed, boolean randomSeed, String seed, boolean keepGameRules) {
         MultiverseWorld world = this.getMVWorld(name);
-        if (world == null)
+        if (world == null) {
+            Logging.warning("Unable to regen a world that does not exist!");
             return false;
+        }
 
         List<Player> ps = world.getCBWorld().getPlayers();
 
+        // Apply new seed if needed.
         if (useNewSeed) {
             long theSeed;
 
@@ -915,19 +931,64 @@ public class WorldManager implements MVWorldManager {
 
             world.setSeed(theSeed);
         }
+
         WorldType type = world.getWorldType();
 
-        if (this.deleteWorld(name, false, false)) {
-            this.doLoad(name, true, type);
-            SafeTTeleporter teleporter = this.plugin.getSafeTTeleporter();
-            Location newSpawn = world.getSpawnLocation();
-            // Send all players that were in the old world, BACK to it!
-            for (Player p : ps) {
-                teleporter.safelyTeleport(null, p, newSpawn, true);
+        // Save current GameRules if needed.
+        Map<GameRule<?>, Object> gameRuleMap = null;
+        if (keepGameRules) {
+            gameRuleMap = new HashMap<>(GameRule.values().length);
+            World CBWorld = world.getCBWorld();
+            for (GameRule<?> gameRule : GameRule.values()) {
+                // Only save if not default value.
+                Object value = CBWorld.getGameRuleValue(gameRule);
+                if (value != CBWorld.getGameRuleDefault(gameRule)) {
+                    gameRuleMap.put(gameRule, value);
+                }
             }
-            return true;
         }
-        return false;
+
+        // Do the regen.
+        if (!this.deleteWorld(name, false, false)) {
+            Logging.severe("Unable to regen world as world cannot be deleted.");
+            return false;
+        }
+        if (!this.doLoad(name, true, type)) {
+            Logging.severe("Unable to regen world as world cannot be loaded.");
+            return false;
+        }
+
+        // Get new MultiverseWorld reference.
+        world = this.getMVWorld(name);
+
+        // Load back GameRules if needed.
+        if (keepGameRules) {
+            Logging.fine("Restoring previous world's GameRules...");
+            World CBWorld = world.getCBWorld();
+            for (Map.Entry<GameRule<?>, Object> gameRuleEntry : gameRuleMap.entrySet()) {
+                if (!setGameRuleValue(CBWorld, gameRuleEntry.getKey(), gameRuleEntry.getValue())) {
+                    Logging.warning("Unable to set GameRule '%s' to '%s' on regen world.",
+                            gameRuleEntry.getKey().getName(), gameRuleEntry.getValue());
+                }
+            }
+        }
+
+        // Send all players that were in the old world, BACK to it!
+        SafeTTeleporter teleporter = this.plugin.getSafeTTeleporter();
+        Location newSpawn = world.getSpawnLocation();
+        for (Player p : ps) {
+            teleporter.safelyTeleport(null, p, newSpawn, true);
+        }
+
+        return true;
+    }
+
+    private <T> boolean setGameRuleValue(World world, GameRule<T> gameRule, Object value) {
+        try {
+            return world.setGameRule(gameRule, (T) value);
+        } catch (Exception e) {
+            return false;
+        }
     }
 
     /**
@@ -953,4 +1014,21 @@ 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/main/java/com/onarandombox/MultiverseCore/utils/metrics/MetricsHelper.java

@@ -1,11 +1,12 @@
 package com.onarandombox.MultiverseCore.utils.metrics;
 
+import org.bstats.charts.AdvancedPie;
+import org.bstats.charts.MultiLineChart;
+
 import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Consumer;
 
-import org.bstats.bukkit.Metrics;
-
 enum MetricsHelper {
     ;
 
@@ -17,16 +18,16 @@ enum MetricsHelper {
         map.put(key, count + 1);
     }
 
-    static Metrics.AdvancedPie createAdvancedPieChart(String chartId, Consumer<Map<String, Integer>> metricsFunc) {
+    static AdvancedPie createAdvancedPieChart(String chartId, Consumer<Map<String, Integer>> metricsFunc) {
         Map<String, Integer> map = new HashMap<>();
         metricsFunc.accept(map);
-        return new Metrics.AdvancedPie(chartId, () -> map);
+        return new AdvancedPie(chartId, () -> map);
     }
 
-    static Metrics.MultiLineChart createMultiLineChart(String chartId, Consumer<Map<String, Integer>> metricsFunc) {
+    static MultiLineChart createMultiLineChart(String chartId, Consumer<Map<String, Integer>> metricsFunc) {
         Map<String, Integer> map = new HashMap<>();
         metricsFunc.accept(map);
-        return new Metrics.MultiLineChart(chartId, () -> map);
+        return new MultiLineChart(chartId, () -> map);
     }
 
 }

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

@@ -30,7 +30,6 @@ import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentMatchers;
-import org.mockito.Matchers;
 import org.mockito.internal.verification.VerificationModeFactory;
 import org.powermock.core.classloader.annotations.PowerMockIgnore;
 import org.powermock.core.classloader.annotations.PrepareForTest;
@@ -38,8 +37,14 @@ import org.powermock.modules.junit4.PowerMockRunner;
 
 import java.io.File;
 
-import static junit.framework.Assert.*;
-import static org.mockito.Mockito.*;
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertNotNull;
+import static junit.framework.Assert.assertTrue;
+import static junit.framework.Assert.fail;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 @RunWith(PowerMockRunner.class)
 @PrepareForTest({ PluginManager.class, MultiverseCore.class, Permission.class, Bukkit.class, WorldManager.class,
@@ -92,7 +97,7 @@ public class TestWorldStuff {
         // Import the first world. The world folder does not exist.
         plugin.onCommand(mockCommandSender, mockCommand, "", normalArgs);
         verify(mockCommandSender).sendMessage(ChatColor.RED + "FAILED.");
-        verify(mockCommandSender).sendMessage("That world folder does not exist. These look like worlds to me:");
+        verify(mockCommandSender).sendMessage(ChatColor.RED + "That world folder does not exist. These look like worlds to me:");
 
         // We should still have no worlds.
         assertEquals(0, creator.getCore().getMVWorldManager().getMVWorlds().size());