Fixed allow-animals not applying to chunk generation.

Moved the legitimacy checking into World.addEntity for better organisation and to better account for future methods being added that control whether or not an entity should spawn.

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

@@ -249,12 +249,8 @@ public class EntityEgg extends Entity {
                             break;
                     }
 
-                    // The world we're spawning in accepts this creature
-                    boolean isAnimal = entity instanceof EntityAnimal || entity instanceof EntityWaterAnimal;
-                    if ((isAnimal && this.world.allowAnimals) || (!isAnimal && this.world.allowMonsters)) {
                     entity.setPositionRotation(this.locX, this.locY, this.locZ, this.yaw, 0.0F);
                     this.world.addEntity(entity, SpawnReason.EGG);
-                    }
                     // CraftBukkit end
                 }
             }

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

@@ -54,13 +54,6 @@ public class TileEntityMobSpawner extends TileEntity {
                         return;
                     }
 
-                    // CraftBukkit start - The world we're spawning in accepts this creature
-                    boolean isAnimal = entityliving instanceof EntityAnimal || entityliving instanceof EntityWaterAnimal;
-                    if ((isAnimal && !this.world.allowAnimals) || (!isAnimal && !this.world.allowMonsters)) {
-                        return;
-                    }
-                    // CraftBukkit end
-
                     int j = this.world.a(entityliving.getClass(), AxisAlignedBB.b((double) this.x, (double) this.y, (double) this.z, (double) (this.x + 1), (double) (this.y + 1), (double) (this.z + 1)).b(8.0D, 4.0D, 8.0D)).size();
 
                     if (j >= 6) {

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

@@ -839,6 +839,13 @@ public class World implements IBlockAccess {
 
         // CraftBukkit start
         if (entity instanceof EntityLiving && !(entity instanceof EntityPlayer)) {
+            boolean isAnimal = entity instanceof EntityAnimal || entity instanceof EntityWaterAnimal;
+            boolean isMonster = entity instanceof EntityMonster || entity instanceof EntityGhast || entity instanceof EntitySlime;
+
+            if (spawnReason == SpawnReason.NATURAL || spawnReason == SpawnReason.SPAWNER || spawnReason == SpawnReason.BED || spawnReason == SpawnReason.EGG) {
+                if (isAnimal && !allowAnimals || isMonster && !allowMonsters) return false;
+            }
+
             CreatureSpawnEvent event = CraftEventFactory.callCreatureSpawnEvent((EntityLiving) entity, spawnReason);
 
             if (event.isCancelled()) {