Less duplicate code ... I think.

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

@@ -0,0 +1,35 @@
+package com.onarandombox.MultiverseCore.listeners;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.AsyncPlayerChatEvent;
+
+/**
+ * A wrapper for the {@link AsyncPlayerChatEvent}.
+ */
+public class AsyncChatEvent implements ChatEvent {
+    private final AsyncPlayerChatEvent event;
+
+    public AsyncChatEvent(AsyncPlayerChatEvent event) {
+        this.event = event;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return event.isCancelled();
+    }
+
+    @Override
+    public String getFormat() {
+        return event.getFormat();
+    }
+
+    @Override
+    public void setFormat(String s) {
+        event.setFormat(s);
+    }
+
+    @Override
+    public Player getPlayer() {
+        return event.getPlayer();
+    }
+}

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

@@ -0,0 +1,29 @@
+package com.onarandombox.MultiverseCore.listeners;
+
+import org.bukkit.entity.Player;
+
+/**
+ * A wrapper for the two chat-events in Bukkit.
+ */
+public interface ChatEvent {
+    /**
+     * @return Whether this event is cancelled.
+     */
+    boolean isCancelled();
+
+    /**
+     * @return The format.
+     */
+    String getFormat();
+
+    /**
+     * Sets the format.
+     * @param s The new format.
+     */
+    void setFormat(String s);
+
+    /**
+     * @return The player.
+     */
+    Player getPlayer();
+}

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

@@ -7,70 +7,28 @@
 
 package com.onarandombox.MultiverseCore.listeners;
 
-import com.onarandombox.MultiverseCore.MultiverseCore;
+import java.util.logging.Level;
-import com.onarandombox.MultiverseCore.api.MVWorldManager;
+
-import com.onarandombox.MultiverseCore.api.MultiverseWorld;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.player.AsyncPlayerChatEvent;
 
-import java.util.logging.Level;
+import com.onarandombox.MultiverseCore.MultiverseCore;
 
 /**
  * Multiverse's {@link org.bukkit.event.Listener} for players.
  */
-public class MVAsyncPlayerChatListener implements MVChatListener<AsyncPlayerChatEvent> {
+public class MVAsyncPlayerChatListener extends MVChatListener {
-
-    private final MultiverseCore plugin;
-    private final MVWorldManager worldManager;
-    private final MVPlayerListener playerListener;
-
     public MVAsyncPlayerChatListener(MultiverseCore plugin, MVPlayerListener playerListener) {
-        this.plugin = plugin;
+        super(plugin, playerListener);
-        this.worldManager = plugin.getMVWorldManager();
+        plugin.log(Level.FINE, "Created AsyncPlayerChatEvent listener.");
-        this.playerListener = playerListener;
-        plugin.log(Level.FINE, "Registered AsyncPlayerChatEvent listener.");
     }
 
     /**
-     * {@inheritDoc}
+     * This method is called when a player wants to chat.
+     * @param event The Event that was fired.
      */
-    @Override
     @EventHandler
     public void playerChat(AsyncPlayerChatEvent event) {
-        if (event.isCancelled()) {
+        this.playerChat(new AsyncChatEvent(event));
-            return;
-        }
-        // Check whether the Server is set to prefix the chat with the World name.
-        // If not we do nothing, if so we need to check if the World has an Alias.
-        if (plugin.getMVConfig().getPrefixChat()) {
-            String world;
-            Thread thread = Thread.currentThread();
-            if (playerListener.getWorldsLock().isLocked()) {
-                plugin.log(Level.FINEST, "worldsLock is locked when attempting to handle player chat on thread: " + thread);
-            }
-            playerListener.getWorldsLock().lock();
-            try {
-                plugin.log(Level.FINEST, "Handling player chat on thread: " + thread);
-                world = playerListener.getPlayerWorld().get(event.getPlayer().getName());
-                if (world == null) {
-                    world = event.getPlayer().getWorld().getName();
-                    playerListener.getPlayerWorld().put(event.getPlayer().getName(), world);
-                }
-            } finally {
-                playerListener.getWorldsLock().unlock();
-            }
-            String prefix = "";
-            // If we're not a MV world, don't do anything
-            if (!this.worldManager.isMVWorld(world)) {
-                return;
-            }
-            MultiverseWorld mvworld = this.worldManager.getMVWorld(world);
-            if (mvworld.isHidden()) {
-                return;
-            }
-            prefix = mvworld.getColoredWorldString();
-            String format = event.getFormat();
-            event.setFormat("[" + prefix + "]" + format);
-        }
     }
 }

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

@@ -1,18 +1,66 @@
 package com.onarandombox.MultiverseCore.listeners;
 
-import org.bukkit.event.Event;
+import java.util.logging.Level;
-import org.bukkit.event.EventHandler;
+
 import org.bukkit.event.Listener;
 
+import com.onarandombox.MultiverseCore.MultiverseCore;
+import com.onarandombox.MultiverseCore.api.MVWorldManager;
+import com.onarandombox.MultiverseCore.api.MultiverseWorld;
+
 /**
- * This interface is implemented by {@link MVPlayerChatListener} and {@link MVAsyncPlayerChatListener}.
+ * Multiverse's {@link org.bukkit.event.Listener} for players.
- * @param <E> The chat event-type.
  */
-public interface MVChatListener<E extends Event> extends Listener {
+public abstract class MVChatListener implements Listener {
+    private final MultiverseCore plugin;
+    private final MVWorldManager worldManager;
+    private final MVPlayerListener playerListener;
+
+    public MVChatListener(MultiverseCore plugin, MVPlayerListener playerListener) {
+        this.plugin = plugin;
+        this.worldManager = plugin.getMVWorldManager();
+        this.playerListener = playerListener;
+    }
+
     /**
-     * This method is called when a player wants to chat.
+     * This handles a {@link ChatEvent}.
-     * @param event The Event that was fired.
+     * @param event The {@link ChatEvent}.
      */
-    @EventHandler
+    public void playerChat(ChatEvent event) {
-    void playerChat(E event);
+        if (event.isCancelled()) {
+            return;
+        }
+        // Check whether the Server is set to prefix the chat with the World name.
+        // If not we do nothing, if so we need to check if the World has an Alias.
+        if (plugin.getMVConfig().getPrefixChat()) {
+            String world;
+            Thread thread = Thread.currentThread();
+            if (playerListener.getWorldsLock().isLocked()) {
+                plugin.log(Level.FINEST, "worldsLock is locked when attempting to handle player chat on thread: " + thread);
+            }
+            playerListener.getWorldsLock().lock();
+            try {
+                plugin.log(Level.FINEST, "Handling player chat on thread: " + thread);
+                world = playerListener.getPlayerWorld().get(event.getPlayer().getName());
+                if (world == null) {
+                    world = event.getPlayer().getWorld().getName();
+                    playerListener.getPlayerWorld().put(event.getPlayer().getName(), world);
+                }
+            } finally {
+                playerListener.getWorldsLock().unlock();
+            }
+            String prefix = "";
+            // If we're not a MV world, don't do anything
+            if (!this.worldManager.isMVWorld(world)) {
+                return;
+            }
+            MultiverseWorld mvworld = this.worldManager.getMVWorld(world);
+            if (mvworld.isHidden()) {
+                return;
+            }
+            prefix = mvworld.getColoredWorldString();
+            String format = event.getFormat();
+            event.setFormat("[" + prefix + "]" + format);
+        }
+    }
 }

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

@@ -7,27 +7,20 @@
 
 package com.onarandombox.MultiverseCore.listeners;
 
-import com.onarandombox.MultiverseCore.MultiverseCore;
+import java.util.logging.Level;
-import com.onarandombox.MultiverseCore.api.MVWorldManager;
+
-import com.onarandombox.MultiverseCore.api.MultiverseWorld;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.player.PlayerChatEvent;
 
-import java.util.logging.Level;
+import com.onarandombox.MultiverseCore.MultiverseCore;
 
 /**
  * Multiverse's {@link org.bukkit.event.Listener} for players.
  */
-public class MVPlayerChatListener implements MVChatListener<PlayerChatEvent> {
+@SuppressWarnings("deprecation") // this exists only for downwards compatibility
-
+public class MVPlayerChatListener extends MVChatListener {
-    private final MultiverseCore plugin;
-    private final MVWorldManager worldManager;
-    private final MVPlayerListener playerListener;
-
     public MVPlayerChatListener(MultiverseCore plugin, MVPlayerListener playerListener) {
-        this.plugin = plugin;
+        super(plugin, playerListener);
-        this.worldManager = plugin.getMVWorldManager();
-        this.playerListener = playerListener;
         plugin.log(Level.FINE, "Registered PlayerChatEvent listener.");
     }
 
@@ -35,43 +28,8 @@ public class MVPlayerChatListener implements MVChatListener<PlayerChatEvent> {
      * This method is called when a player wants to chat.
      * @param event The Event that was fired.
      */
-    @Override
     @EventHandler
     public void playerChat(PlayerChatEvent event) {
-        if (event.isCancelled()) {
+        this.playerChat(new NormalChatEvent(event));
-            return;
-        }
-        // Check whether the Server is set to prefix the chat with the World name.
-        // If not we do nothing, if so we need to check if the World has an Alias.
-        if (plugin.getMVConfig().getPrefixChat()) {
-            String world;
-            Thread thread = Thread.currentThread();
-            if (playerListener.getWorldsLock().isLocked()) {
-                plugin.log(Level.FINEST, "worldsLock is locked when attempting to handle player chat on thread: " + thread);
-            }
-            playerListener.getWorldsLock().lock();
-            try {
-                plugin.log(Level.FINEST, "Handling player chat on thread: " + thread);
-                world = playerListener.getPlayerWorld().get(event.getPlayer().getName());
-                if (world == null) {
-                    world = event.getPlayer().getWorld().getName();
-                    playerListener.getPlayerWorld().put(event.getPlayer().getName(), world);
-                }
-            } finally {
-                playerListener.getWorldsLock().unlock();
-            }
-            String prefix = "";
-            // If we're not a MV world, don't do anything
-            if (!this.worldManager.isMVWorld(world)) {
-                return;
-            }
-            MultiverseWorld mvworld = this.worldManager.getMVWorld(world);
-            if (mvworld.isHidden()) {
-                return;
-            }
-            prefix = mvworld.getColoredWorldString();
-            String format = event.getFormat();
-            event.setFormat("[" + prefix + "]" + format);
-        }
     }
 }

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

@@ -0,0 +1,37 @@
+package com.onarandombox.MultiverseCore.listeners;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerChatEvent;
+
+/**
+ * A wrapper for the {@link PlayerChatEvent}.
+ * @deprecated This is deprecated like the {@link PlayerChatEvent}.
+ */
+@Deprecated
+public class NormalChatEvent implements ChatEvent {
+    private final PlayerChatEvent event;
+
+    public NormalChatEvent(PlayerChatEvent event) {
+        this.event = event;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return event.isCancelled();
+    }
+
+    @Override
+    public String getFormat() {
+        return event.getFormat();
+    }
+
+    @Override
+    public void setFormat(String s) {
+        event.setFormat(s);
+    }
+
+    @Override
+    public Player getPlayer() {
+        return event.getPlayer();
+    }
+}