gamelistener.java

a java game code for java

package eatbean.event;

import eatbean.Debug;
//
import java.util.EventListener;
import java.util.Vector;

/**
 * Title:        吃豆子
 * Description:  小游戏
 * Copyright:    Copyright (c) 2002
 * Company:      Raindrop
 * @author       一无所有
 * @version 1.0
 */

/** 消息发送后立即返回,然后再由processMsg处理 */
public abstract class GameListener extends Thread implements EventListener {
	private Vector msgQueue = new Vector();
	private boolean keepRunning = true;
	public GameListener() {
	    this.start();
	}
	public final void run() {
		GameEvent msg;
		while(keepRunning) {
		    msg = getMsg();
			processMsg(msg);
		}
		while(!msgQueue.isEmpty()) {
			//处理剩余消息
			msg = (GameEvent)removeFirst(msgQueue);
			processMsg(msg);
		}
	}
	private final void processMsg(GameEvent msg) {
		if(msg == null) return;
		switch(msg.getMsgId()) {
			case GameEvent.MSG_OBJECT_EAT :
				objectEat(msg);
				break;
			case GameEvent.MSG_ACTOR_EAT :
				actorEat(msg);
				break;
			case GameEvent.MSG_STATION_DONE :
				stationDone(msg);
				break;
			default :
				if(Debug.ON) Debug.println("GameListener.processMsg() : 无法识别的消息类型");
		}
	}
	private synchronized GameEvent getMsg() {
		GameEvent result = null;
		if(msgQueue.isEmpty())
			try {
				wait(); //释放对象锁,等待notify
			} catch(Exception ex) {}
		else {
			result = (GameEvent)removeFirst(msgQueue);
		}
		return result;
	}
	public synchronized void postMsg(GameEvent msg) {
		if(!keepRunning) return;
		msgQueue.addElement(msg);
		notifyAll();    //唤醒getMsg();
	}
	public synchronized void free() {
		//有待改进
		keepRunning = false;
		notifyAll();
	}
	private Object removeFirst(Vector v) {
		Object result;
		result = v.elementAt(0);
		v.removeElementAt(0);
		return result;
	}

	/** 豆子或其他特殊对象被Fairy吃 */
	abstract protected void objectEat(GameEvent e);
	/** Fairy或Sprite对象被吃 */
	abstract protected void actorEat(GameEvent e);
	/** 所有的豆豆被吃完 */
	abstract protected void stationDone(GameEvent e);
}