责任链模式

类：beater 击鼓者
package beat;

import java.util.Timer;
import java.util.TimerTask;

public class Beater {
	public static boolean stopped = false;
	private static Player firstPlayer = null;
	private Timer timer;

	class Task extends TimerTask {
		public void run() {
			stopped = true;
			System.out.println("鼓声已停");
		}
	}

	public void startBeating(int seconds) {
		timer = new Timer();
		System.out.println("开始击鼓");
		timer.schedule(new Task(), seconds);
	}

	public static void main(String[] args) {
		Beater beater = new Beater();
	    PlayerA A = new PlayerA(null);
	    A.setSuccessoer(new PlayerB(new PlayerC(new PlayerD(A))));
	    beater.startBeating(2);//计时的时间为2秒
	    firstPlayer=A;//从A开始
	    A.handle();
	}

}
抽象类：Player

package beat;

public abstract class Player {
private Player successor;
public abstract void handle();
public Player(){
	successor = null;
}
protected void setSuccessoer(Player successor){
	this.successor = successor;
}
public void next(){
	if(successor!=null){
		successor.handle();
	}else{
		System.out.println("没有下一个接替者了");
		System.exit(0);
	}
}
}

具体类：PlayerA
package beat;

public class PlayerA extends Player {
	public PlayerA(Player successor){
		this.setSuccessoer(successor);
	}
	@Override
	public void handle() {
	if(Beater.stopped){
		System.out.println("A must have a drink");
	}else{
		System.out.println("A just passed");
		next();
	}

	}

}
//以下的PlayerB,PlayerC,PlayerD省略了