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