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Java-马士兵设计模式学习笔记-观察者模式-OOD 封装Listener

2023-09-27 14:24:53 时间

 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

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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