Implemented World.spawnBoat(), added CraftMappable interface that defines a method to get an org.bukkit.craftbukkit.CraftEntity from implementing net.minecart.server.Entity entities, changed CraftWorld.toCraftEntity() to use this new interface for boats and minecarts.

src/main/java/net/minecraft/server/EntityBoat.java

@@ -4,6 +4,8 @@ import java.util.List;
 
 import org.bukkit.Location;
 import org.bukkit.craftbukkit.CraftBoat;
+import org.bukkit.craftbukkit.CraftEntity;
+import org.bukkit.craftbukkit.CraftMappable;
 import org.bukkit.craftbukkit.CraftMinecart;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.event.Event.Type;
@@ -13,9 +15,9 @@ import org.bukkit.event.vehicle.VehicleEnterEvent;
 import org.bukkit.event.vehicle.VehicleEntityCollisionEvent;
 import org.bukkit.event.vehicle.VehicleMoveEvent;
 
-public class EntityBoat extends Entity {
+public class EntityBoat extends Entity implements CraftMappable {
 
-    public CraftBoat boat;
+    private CraftBoat boat;
 
     public int a;
     public int b;
@@ -27,6 +29,10 @@ public class EntityBoat extends Entity {
     private double ak;
     private double al;
 
+    public CraftEntity getCraftEntity() {
+        return boat;
+    }
+
     public EntityBoat(World world) {
         super(world);
         a = 0;

src/main/java/net/minecraft/server/EntityMinecart.java

@@ -4,15 +4,17 @@ import java.util.List;
 
 import org.bukkit.Location;
 import org.bukkit.Vector;
+import org.bukkit.craftbukkit.CraftEntity;
+import org.bukkit.craftbukkit.CraftMappable;
 import org.bukkit.craftbukkit.CraftMinecart;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.event.Event.Type;
 import org.bukkit.event.vehicle.*;
 
 public class EntityMinecart extends Entity
-        implements IInventory {
+        implements IInventory, CraftMappable {
 
-    public CraftMinecart minecart;
+    private CraftMinecart minecart;
     
     private ItemStack ak[];
     public int a;
@@ -99,7 +101,11 @@ public class EntityMinecart extends Entity
     private double derailedZ = 0.5;
     private double flyingX = 0.94999998807907104;
     private double flyingY = 0.94999998807907104;
-    private double flyingZ = 0.94999998807907104;
+    private double flyingZ = 0.94999998807907104;
+
+    public CraftEntity getCraftEntity() {
+        return minecart;
+    }
 
     public EntityMinecart(World world) {
         super(world);

src/main/java/org/bukkit/craftbukkit/CraftMappable.java

@@ -0,0 +1,16 @@
+package org.bukkit.craftbukkit;
+
+/**
+ * Indicates that an object has a method to get its CraftBukkit-equivalent
+ * CraftEntity object from its Minecraft net.minecraft.server.Entity object.
+ * 
+ * @author sk89q
+ */
+public interface CraftMappable {
+    /**
+     * Gets the CraftEntity version.
+     * 
+     * @return
+     */
+    public CraftEntity getCraftEntity();
+}

src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -7,6 +7,7 @@ import java.util.Map;
 import net.minecraft.server.EntityMinecart;
 import java.util.Random;
 
+import net.minecraft.server.EntityBoat;
 import net.minecraft.server.EntityEgg;
 import net.minecraft.server.EntityLiving;
 import net.minecraft.server.EntityPlayerMP;
@@ -18,6 +19,7 @@ import net.minecraft.server.WorldServer;
 import net.minecraft.server.WorldGenTrees;
 import org.bukkit.Arrow;
 import org.bukkit.Block;
+import org.bukkit.Boat;
 import org.bukkit.Chunk;
 import org.bukkit.Location;
 import org.bukkit.Minecart;
@@ -144,6 +146,13 @@ public class CraftWorld implements World {
         return new CraftPoweredMinecart(world.getServer(), minecart);
     }
     
+    public Boat spawnBoat(Location loc) {
+        EntityBoat boat =
+            new EntityBoat(world, loc.getX(), loc.getY(), loc.getZ());
+        world.a(boat);
+        return new CraftBoat(world.getServer(), boat);
+    }
+    
     public boolean generateTree(Location loc) {
         WorldGenTrees treeGen = new WorldGenTrees();
         return treeGen.a(world, rand,
@@ -165,18 +174,12 @@ public class CraftWorld implements World {
             return new CraftPlayer(world.getServer(), (EntityPlayerMP)entity);
         } else if (entity instanceof EntitySnowball) {
             return new CraftSnowball(world.getServer(), (EntitySnowball)entity);
-        } else if (entity instanceof EntityMinecart) {
-            EntityMinecart minecart = (EntityMinecart)entity;
-            if (minecart.minecart != null) {
-                return minecart.minecart;
-            }
-            
-            return CraftMinecart.getCraftMinecart(world.getServer(),
-                    (EntityMinecart)entity);
         } else if (entity instanceof EntityPlayer) {
             return new CraftHumanEntity(world.getServer(), (EntityPlayer)entity);
         } else if (entity instanceof EntityLiving) {
             return new CraftLivingEntity(world.getServer(), (EntityLiving)entity);
+        } else if (entity instanceof CraftMappable) {
+            return ((CraftMappable)entity).getCraftEntity();
         } else {
             return null;
         }