CommonEventFactory.java

package com.bergerkiller.bukkit.common.events;

import java.util.ArrayList;
import java.util.List;

import net.minecraft.server.BiomeMeta;
import net.minecraft.server.Entity;

import org.bukkit.World;
import org.bukkit.entity.EntityType;

import com.bergerkiller.bukkit.common.collections.InstanceBuffer;
import com.bergerkiller.bukkit.common.entity.CommonEntityType;
import com.bergerkiller.bukkit.common.internal.CommonNMS;
import com.bergerkiller.bukkit.common.reflection.FieldAccessor;
import com.bergerkiller.bukkit.common.reflection.SafeField;
import com.bergerkiller.bukkit.common.utils.CommonUtil;
import com.bergerkiller.bukkit.common.utils.LogicUtil;
import com.bergerkiller.bukkit.common.utils.WorldUtil;

/**
 * Processes server happenings and raises events accordingly
 */
public class CommonEventFactory {
	private final EntityMoveEvent entityMoveEvent = new EntityMoveEvent();
	private final List<Entity> entityMoveEntities = new ArrayList<Entity>();
	private final CreaturePreSpawnEvent creaturePreSpawnEvent = new CreaturePreSpawnEvent();
	private final FieldAccessor<Integer> biomeMetaChance = new SafeField<Integer>(BiomeMeta.class, "a");
	private final InstanceBuffer<BiomeMeta> creaturePreSpawnMobs = new InstanceBuffer<BiomeMeta>() {
		@Override
		public BiomeMeta createElement() {
			return new BiomeMeta(null, 0, 0, 0);
		}
	};

	/**
	 * Fires Entity Move events for all entities that moved on the server
	 */
	public void handleEntityMove() {
		if (!CommonUtil.hasHandlers(EntityMoveEvent.getHandlerList())) {
			return;
		}
		for (World world : WorldUtil.getWorlds()) {
			entityMoveEntities.addAll(CommonNMS.getEntities(world));
		}
		for (Entity entity : entityMoveEntities) {
			if (entity.locX != entity.lastX || entity.locY != entity.lastY || entity.locZ != entity.lastZ 
					|| entity.yaw != entity.lastYaw || entity.pitch != entity.lastPitch) {

				entityMoveEvent.setEntity(entity);
				CommonUtil.callEvent(entityMoveEvent);
			}
		}
		entityMoveEntities.clear();
	}

	/**
	 * Handles the spawning of creatures on the server
	 * 
	 * @param world
	 * @param x
	 * @param y
	 * @param z
	 * @param inputTypes to process and fire events for
	 * @return a list of mobs to spawn
	 */
	public List<BiomeMeta> handleCreaturePreSpawn(World world, int x, int y, int z, List<BiomeMeta> inputTypes) {
		// Shortcuts
		if (LogicUtil.nullOrEmpty(inputTypes) || !CommonUtil.hasHandlers(CreaturePreSpawnEvent.getHandlerList())) {
			return inputTypes;
		}

		// Start processing the elements
		creaturePreSpawnMobs.clear();
		for (BiomeMeta inputMeta : inputTypes) {
			final EntityType oldEntityType = CommonEntityType.byNMSEntityClass(inputMeta.b).entityType;

			// Set up the event
			creaturePreSpawnEvent.cancelled = false;
			creaturePreSpawnEvent.spawnLocation.setWorld(world);
			creaturePreSpawnEvent.spawnLocation.setX(x);
			creaturePreSpawnEvent.spawnLocation.setY(y);
			creaturePreSpawnEvent.spawnLocation.setZ(z);
			creaturePreSpawnEvent.spawnLocation.setYaw(0.0f);
			creaturePreSpawnEvent.spawnLocation.setPitch(0.0f);
			creaturePreSpawnEvent.entityType = oldEntityType;
			creaturePreSpawnEvent.minSpawnCount = inputMeta.c;
			creaturePreSpawnEvent.maxSpawnCount = inputMeta.d;

			// Raise it and handle spawn cancel
			if (CommonUtil.callEvent(creaturePreSpawnEvent).isCancelled() || (creaturePreSpawnEvent.minSpawnCount == 0 && creaturePreSpawnEvent.maxSpawnCount == 0)) {
				continue;
			}

			// Handle a possibly changed entity type
			final Class<?> entityClass;
			if (oldEntityType == creaturePreSpawnEvent.entityType) {
				entityClass = inputMeta.b;
			} else {
				entityClass = CommonEntityType.byEntityType(creaturePreSpawnEvent.entityType).nmsType.getType();
				// Unknown or unsupported Entity Type - ignore spawning
				if (entityClass == null) {
					continue;
				}
			}

			// Add element to buffer
			final BiomeMeta outputMeta = creaturePreSpawnMobs.add();
			outputMeta.b = entityClass;
			outputMeta.c = creaturePreSpawnEvent.minSpawnCount;
			outputMeta.d = creaturePreSpawnEvent.maxSpawnCount;
			biomeMetaChance.transfer(inputMeta, outputMeta);
		}
		return creaturePreSpawnMobs;
	}
}