發布者訂閱者模式之JAVA實現

 

 

 

 

1.發布者接口

package com.shoshana.publishsubscribe;

public interface IPublisher<M> {
    public void publish(SubscribePublish subscribePublish, M message, boolean isInstantMsg);
}

　　

 

2.訂閱者接口

 

package com.shoshana.publishsubscribe;

public interface ISubcriber<M> {
    public void subcribe(SubscribePublish subscribePublish);

    public void unSubcribe(SubscribePublish subscribePublish);

    public void update(String publisher, M message);
}

　　

 

3.訂閱器類

package com.shoshana.publishsubscribe;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

public class SubscribePublish<M> {
    //訂閱器名稱
    private String name;
    //訂閱器隊列容量
    final int QUEUE_CAPACITY = 20;
    //訂閱器存儲隊列
    private BlockingQueue<Msg> queue = new ArrayBlockingQueue<Msg>(QUEUE_CAPACITY);
    //訂閱者
    private List<ISubcriber> subcribers = new ArrayList<ISubcriber>();

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

    public void publish(String publisher, M message, boolean isInstantMsg) {
        if (isInstantMsg) {
            update(publisher, message);
            return;
        }
        Msg<M> m = new Msg<M>(publisher, message);
        if (!queue.offer(m)) {
            update();
        }
    }

    public void subcribe(ISubcriber subcriber) {
        subcribers.add(subcriber);
    }

    public void unSubcribe(ISubcriber subcriber) {
        subcribers.remove(subcriber);
    }

    public void update() {
        Msg m = null;
        while ((m = queue.peek()) != null) {
            this.update(m.getPublisher(), (M) m.getMsg());
        }
    }

    public void update(String publisher, M Msg) {
        for (ISubcriber subcriber : subcribers) {
            subcriber.update(publisher, Msg);
        }
    }
}

class Msg<M> {
    private String publisher;
    private M m;

    public Msg(String publisher, M m) {
        this.publisher = publisher;
        this.m = m;
    }

    public String getPublisher() {
        return publisher;
    }

    public void setPublisher(String publisher) {
        this.publisher = publisher;
    }

    public M getMsg() {
        return m;
    }

    public void setMsg(M m) {
        this.m = m;
    }
}

　

4.發布者實現類

package com.shoshana.publishsubscribe;

public class PublisherImpOne<M> implements IPublisher<M> {
    private String name;

    public PublisherImpOne(String name) {
        super();
        this.name = name;
    }

    public void publish(SubscribePublish subscribePublish, M message, boolean isInstantMsg) {
        subscribePublish.publish(this.name, message, isInstantMsg);
    }
}

　　

　

5.訂閱者實現類　

package com.shoshana.publishsubscribe;

public class SubcriberImpOne<M> implements ISubcriber<M> {
    public String name;

    public SubcriberImpOne(String name) {
        super();
        this.name = name;
    }

    public void subcribe(SubscribePublish subscribePublish) {
        subscribePublish.subcribe(this);
    }

    public void unSubcribe(SubscribePublish subscribePublish) {
        subscribePublish.unSubcribe(this);
    }

    public void update(String publisher, M message) {
        System.out.println(this.name + "收到" + publisher + "發來的消息:" + message.toString());
    }
}

　　

6.測試類

package com.shoshana.publishsubscribe;

public class SubPubTest {
    public static void main(String[] args) {
        SubscribePublish<String> subscribePublish = new SubscribePublish<String>("訂閱器");
        IPublisher<String> publisher1 = new PublisherImpOne<String>("發布者1");
        ISubcriber<String> subcriber1 = new SubcriberImpOne<String>("訂閱者1");
        ISubcriber<String> subcriber2 = new SubcriberImpOne<String>("訂閱者2");
        subcriber1.subcribe(subscribePublish);
        subcriber2.subcribe(subscribePublish);
        publisher1.publish(subscribePublish, "welcome", true);
        publisher1.publish(subscribePublish, "to", true);
        publisher1.publish(subscribePublish, "yy", false);
    }
}

測試結果:

com.shoshana.publishsubscribe.SubPubTest
訂閱者1收到發布者1發來的消息:welcome
訂閱者2收到發布者1發來的消息:welcome
訂閱者1收到發布者1發來的消息:to
訂閱者2收到發布者1發來的消息:to

Process finished with exit code 0