JAVA支持的观察者模式

JAVA支持的观察者模式，适用jdk自带的Observer、Observable

package com.wh.cms.webinfo.observer;

import java.util.Observable;
import java.util.Observer;

/**
 * 观察者
 * Created by zyb on 15/11/12.
 */
public class Watcher implements Observer {
    public Watcher(Observable o) {
        o.addObserver(this);
    }

    /**
     * 接收所有被观察者消息
     *
     * @param o
     * @param arg
     */
    @Override
    public void update(Observable o, Object arg) {
        Object obj = o.getClass();
        if (obj.equals(Watched.class)) {
            System.out.println("Watched状态发生改变：" + ((Watched) o).getWatcherState());
        } else if (obj.equals(Watched2.class)) {
            System.out.println("Watched2状态发生改变：" + ((Watched2) o).getWatcherState());
        }
    }
}

package com.wh.cms.webinfo.observer;

import java.util.Observable;

/**
 * 被观察者
 * Created by zyb on 15/11/12.
 */
public class Watched extends Observable {
    /**
     * 观察者监听状态
     */
    private String watcherState = "";

    public String getWatcherState() {
        return watcherState;
    }

    public void setWatcherState(String watcherState) {
        if (!this.watcherState.equals(watcherState)) {
            this.watcherState = watcherState;
            setChanged();//更新状态
        }
        notifyObservers(); //更新提醒
    }
}

package com.wh.cms.webinfo.observer;

import java.util.Observable;

/**
 * 被观察者
 * Created by zyb on 15/11/12.
 */
public class Watched2 extends Observable {
    /**
     * 观察者监听状态
     */
    private String watcherState = "";

    public String getWatcherState() {
        return watcherState;
    }

    public void setWatcherState(String watcherState) {
        if (!this.watcherState.equals(watcherState)) {
            this.watcherState = watcherState;
            setChanged();//更新状态
        }
        notifyObservers(); //更新提醒
    }
}

package com.wh.cms.webinfo.observer;

import java.util.Observer;

/**
 * Created by zyb on 15/11/12.
 */
public class Test {
    public static void main(String[] args) {

        //创建被观察者对象
        Watched watched = new Watched();
        Watched2 watched2 = new Watched2();

        //创建观察者对象，并将被观察者对象登记
        Observer watcher = new Watcher(watched);
        Observer watcher2 = new Watcher(watched2);

        //给被观察者状态赋值
        watched.setWatcherState("start");
        watched.setWatcherState("run");
        watched.setWatcherState("stop");
        watched.setWatcherState("hahaha");

        watched2.setWatcherState("start");
        watched2.setWatcherState("run");
        watched2.setWatcherState("stop");
        watched2.setWatcherState("hahaha");
    }
}