Java-马士兵设计模式学习笔记-观察者模式-OOD 封装Listener

 一、概述

childe类中的是关联监听者dad的，若要再增加监听者，会很不方便，且要修改代码。好的方法是封装监听者类，用addListener()方法动态添加监听者

 

二、代码

1.Test.java

class WakenUpEvent{

	

	private long time;

	private String location;

	private Child source;

	

	public WakenUpEvent(long time, String location, Child source) {

		super();

		this.time = time;

		this.location = location;

		this.source = source;

	}



	public long getTime() {

		return time;

	}



	public void setTime(long time) {

		this.time = time;

	}



	public String getLocation() {

		return location;

	}



	public void setLocation(String location) {

		this.location = location;

	}



	public Child getSource() {

		return source;

	}



	public void setSource(Child source) {

		this.source = source;

	}

	

	

}



class Child implements Runnable {

	

	private List<WakenUpListener> wakenUpListeners = new ArrayList<WakenUpListener>();

	

	public void addWakenUpListener(WakenUpListener wul){

		wakenUpListeners.add(wul);

	}

	public void wakeUp(){

		for(int i = 0; i < wakenUpListeners.size(); i++){

			WakenUpListener l = wakenUpListeners.get(i);

			l.actionToWakenUp(new WakenUpEvent(System.currentTimeMillis(), "bed", this));

		}

	}



	@Override

	public void run() {

		try {

			Thread.sleep(3000);

		} catch (Exception e) {

			e.printStackTrace();

		}

		wakeUp();

	}

}





interface WakenUpListener {

	public void actionToWakenUp(WakenUpEvent e);

}



class Dad implements WakenUpListener {



	public void actionToWakenUp(WakenUpEvent e) {

		System.out.println("Fedd the child");

	}

	

}



class GrandFather implements WakenUpListener {



	public void actionToWakenUp(WakenUpEvent e) {

		System.out.println("抱孩子");

	}

	

}





public class Test {



	public static void main(String[] args) {

		Child c = new Child();

		c.addWakenUpListener(new Dad());

		c.addWakenUpListener(new GrandFather());

		new Thread(c).start();

	}

}

　　

三、运行结果