Add PlayerChangedMainHandEvent

src/main/java/org/bukkit/entity/HumanEntity.java

@@ -38,7 +38,7 @@ public interface HumanEntity extends LivingEntity, AnimalTamer, Permissible, Inv
     public Inventory getEnderChest();
 
     /**
-     * Gets the players selected main hand
+     * Gets the player's selected main hand
      *
      * @return the players main hand
      */

src/main/java/org/bukkit/event/player/PlayerChangedMainHandEvent.java

@@ -0,0 +1,39 @@
+package org.bukkit.event.player;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+import org.bukkit.inventory.MainHand;
+
+/**
+ * Called when a player changes their main hand in the client settings.
+ */
+public class PlayerChangedMainHandEvent extends PlayerEvent {
+
+    private static final HandlerList handlers = new HandlerList();
+    //
+    private final MainHand mainHand;
+
+    public PlayerChangedMainHandEvent(Player who, MainHand mainHand) {
+        super(who);
+        this.mainHand = mainHand;
+    }
+
+    /**
+     * Gets the new main hand of the player. The old hand is still momentarily
+     * available via {@link Player#getMainHand()}.
+     *
+     * @return the new {@link MainHand} of the player
+     */
+    public MainHand getMainHand() {
+        return mainHand;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+}