事件处理模型:

组件(事件源)不处理自己的事件,而是将事件处理托付给外部的处理实体（监听器,

这样的事件处理模型称为事件的 授权处理模型。

不同的事件，能够交由不同类型的监听器去处理

事件源:

提供订阅与取消监听者的方法，并负责维护监听者列表，发送事件给监听者

监听者:

每一个监听者实现接口来接收事件,并负责从事件源订阅与取消订阅

图示:

demo

事件源:

Context:

package com.demo.event; import java.util.ArrayList; import java.util.List; public class Context { private static List<Listener> list=new ArrayList<Listener>(); public static void addListener(Listener listener){ list.add(listener); } public static void removeListener(Listener listener){ list.remove(listener); } public static void sendNotification(Event event){ for(Listener listener:list){ listener.onChange(event); } } }

监听者:

Listener

package com.demo.event; public interface Listener { public void onChange(Event event); } MyListener

package com.demo.event; public class MyListener implements Listener { @Override public void onChange(Event event) { switch(event.getType()){ case Event.INSTALLED: System.out.println("do install..."); break; case Event.STARTED : System.out.println("do started..."); break; case Event.RESOLVED : System.out.println("do resolved..."); break; case Event.STOPPED : System.out.println("do stopped..."); break; case Event.UNRESOLVED : System.out.println("do unresolved..."); break; case Event.UNINSTALLED : System.out.println("do uninstalled..."); break; default: throw new IllegalArgumentException(); } } }

事件:

package com.demo.event; public class Event { public static final int INSTALLED =1; public static final int STARTED =2; public static final int RESOLVED =3; public static final int STOPPED =4; public static final int UNRESOLVED =5; public static final int UNINSTALLED =6; private int type ; private Object source ; public Event(int type, Object source) { this.type = type; this.source = source; } public int getType() { return type; } public Object getSource() { return source; } }

測试:

package com.demo.event; public class EventTest { /** * @param args */ public static void main(String[] args) { Listener listener=new MyListener(); //加入监听者 Context.addListener(listener); //模拟bundle安装完毕事件触发 Context.sendNotification(new Event(Event.INSTALLED, new MyBundle())); } }

转载于:https://www.cnblogs.com/bhlsheji/p/4286667.html

相关资源：Java设计模式之监听器模式实例详解