Guarded Suspension 模式

Guarded Suspension 模式通过让线程等待保证线程的安全性。

实际案例

类信息概览：

类名 说明
Main.java 方法的总入口
ClientThread.java 发送请求的类
ServerThread.java 接受请求的类
RequestQueue.java 依次存放请求的类
Request.java 标识一个请求的类

定义

  • ClientThread.java
package com.github.houbb.thread.learn.easy.learn.guarded.suspension;

import java.util.Random;

public class ClientThread extends Thread {

    private final Random random;

    private final RequestQueue requestQueue;

    public ClientThread(RequestQueue requestQueue, final String name, final long seed) {
        super(name);
        this.requestQueue = requestQueue;
        random = new Random(seed);
    }

    @Override
    public void run() {
        for(int i = 0; i < 10; i++) {
            Request request = new Request("No. " + i);
            requestQueue.putRequest(request);
            System.out.println(Thread.currentThread().getName() + " put " + request);
            try {
                Thread.sleep(random.nextInt(1000));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

}
  • ServerThread.java
package com.github.houbb.thread.learn.easy.learn.guarded.suspension;

import java.util.Random;

public class ServerThread extends Thread {

    private final Random random;

    private final RequestQueue requestQueue;

    public ServerThread(RequestQueue requestQueue, final String name, final long seed) {
        super(name);
        this.requestQueue = requestQueue;
        random = new Random(seed);
    }

    @Override
    public void run() {
        for(int i = 0; i < 10; i++) {
            Request request = requestQueue.getRequest();
            System.out.println(Thread.currentThread().getName()+" get "+request);
            try {
                Thread.sleep(random.nextInt(1000));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

}
  • RequestQueue.java
package com.github.houbb.thread.learn.easy.learn.guarded.suspension;

import java.util.LinkedList;
import java.util.Queue;

public class RequestQueue {

    private Queue<Request> requestQueue = new LinkedList<>();

    /**
     * 获取一个对象
     * 1. 如果队列为空，则一直等待。
     * @return
     */
    public synchronized Request getRequest() {
        while(requestQueue.peek() == null) {
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        // Retrieves and removes the head of this queue.
        return requestQueue.remove();
    }

    /**
     * 放置一个对象
     * @param request
     */
    public synchronized void putRequest(Request request) {
        requestQueue.add(request);

        notifyAll();
    }

}
  • Request.java
package com.github.houbb.thread.learn.easy.learn.guarded.suspension;

/**
 * 请求参数
 * @version 1.0.0
 * @author bbhou
 * @since 1.0.0
 */
public class Request {

    private final String name;

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

    public String getName() {
        return name;
    }

    @Override
    public String toString() {
        return "Request{" +
                "name='" + name + '\'' +
                '}';
    }
}

测试

  • Main.java
package com.github.houbb.thread.learn.easy.learn.guarded.suspension;

public class Main {

    public static void main(String[] args) {
        RequestQueue requestQueue = new RequestQueue();
        new ClientThread(requestQueue, "CLIENT", 10000L).start();
        new ServerThread(requestQueue, "SERVER", 20000L).start();
    }

}
  • 测试结果
CLIENT put Request{name='No. 0'}
SERVER get Request{name='No. 0'}
CLIENT put Request{name='No. 1'}
SERVER get Request{name='No. 1'}
CLIENT put Request{name='No. 2'}
CLIENT put Request{name='No. 3'}
SERVER get Request{name='No. 2'}
SERVER get Request{name='No. 3'}
CLIENT put Request{name='No. 4'}
CLIENT put Request{name='No. 5'}
SERVER get Request{name='No. 4'}
CLIENT put Request{name='No. 6'}
CLIENT put Request{name='No. 7'}
SERVER get Request{name='No. 5'}
CLIENT put Request{name='No. 8'}
SERVER get Request{name='No. 6'}
CLIENT put Request{name='No. 9'}
SERVER get Request{name='No. 7'}
SERVER get Request{name='No. 8'}
SERVER get Request{name='No. 9'}

实现方式

UML & Code

UML

UML 图示如下

UML

Code

代码地址

Guarded Suspension

系列导航

多线程系列导航