观察者模式

package cn.lxl.observe;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2011-11-11
 * Time: 15:30:25
 * To change this template use File | Settings | File Templates.
 */
//抽象主题
public interface AbstractMotif {

    public void addAbstractMotif(AbstractWatcher abstractWatcher);

    public void removeAbstractMotif(AbstractWatcher abstractWatcher);

    public void notifyAbstractMotif(String message);
}

 

package cn.lxl.observe;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2011-11-11
 * Time: 15:33:19
 * To change this template use File | Settings | File Templates.
 */
public interface AbstractWatcher {
    public void update(String message);
}

 

package cn.lxl.observe;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2011-11-11
 * Time: 15:46:47
 * To change this template use File | Settings | File Templates.
 */
public class ConWatcher implements AbstractWatcher {
    // 定义每一个观察者名字
    private String name;

    public ConWatcher(String name) {
        this.name = name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return this.name;
    }

    //接受信息
    public void update(String message) {
        System.out.println(message);
    }
}

 

package cn.lxl.observe;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2011-11-11
 * Time: 15:31:26
 * To change this template use File | Settings | File Templates.
 */
//具体主题
public class ConMotif implements AbstractMotif {
    //观察都列表
    List list = new ArrayList();

    // 增加观察者
    @Override
    public void addAbstractMotif(AbstractWatcher abstractWatcher) {
        list.add(abstractWatcher);
        ConWatcher con = (ConWatcher) abstractWatcher;
        String conName = con.getName();
        System.out.println("增加了一个新观察者..." + conName);
    }

    //删除观察者
    @Override
    public void removeAbstractMotif(AbstractWatcher abstractWatcher) {
        list.remove(abstractWatcher);
        ConWatcher con = (ConWatcher) abstractWatcher;
        String conName = con.getName();
        System.out.println("删除了一个新观察者..." + conName);
    }

    //观察者发送信息
    @Override
    public void notifyAbstractMotif(String message) {
        for (AbstractWatcher abstractWatcher : list) {
            ConWatcher con = (ConWatcher) abstractWatcher;
            String conName = con.getName();
            abstractWatcher.update("现在还有:" + conName + "在" + message);
        }
    }
}

 

package cn.lxl.observe;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2011-11-11
 * Time: 15:48:29
 * To change this template use File | Settings | File Templates.
 */
public class Test {
    public static void main(String[] args) {
        //生成一个具体的被观察对象
        ConMotif conMotif = new ConMotif();

        //生成观察者张三
        ConWatcher zsConWatcher = new ConWatcher("张三");

        //生成观察者李四
        ConWatcher lsConWatcher = new ConWatcher("李四");

        //生成观察者王五
        ConWatcher wwConWatcher = new ConWatcher("王五");

        //观察者观察具休珠对象
        conMotif.addAbstractMotif(zsConWatcher);
        conMotif.addAbstractMotif(lsConWatcher);
        conMotif.addAbstractMotif(wwConWatcher);


        conMotif.removeAbstractMotif(wwConWatcher);

        conMotif.notifyAbstractMotif("观察我");
    }
}