java多线程编程--工作线程模式《java多线程编程调试模式》

一.本例来自《java多线程编程调试模式》：

题意：模拟流水线上的工人，

 工人一直在流水线上作业，零件（可看作客户端发的请求）一到达，工人就开始进行工作，无零件时工作处于等待状态

具体的业务代码有详注释：

一测试类：

package worker.thread.pattern;

public class Main {
    public static void main(String[] args) {
    	 Channel channel = new Channel(5);   // Worker Thread数量
         channel.startWorkers();
         ClientThread alice = new ClientThread("Alice", channel);
         ClientThread bobby = new ClientThread("Bobby", channel);
         ClientThread chris = new ClientThread("Chris", channel);
         alice.start();
         bobby.start();
         chris.start();

         try {
             Thread.sleep(5000);
         } catch (InterruptedException e) {
         }
         alice.stopThread();
         bobby.stopThread();
         chris.stopThread();
         channel.stopAllWorkers();
    }
}

2.客户端类：主要发送工作请求

package worker.thread.pattern;

import java.util.Random;

/**
 * 不停的发送请求给工人类
 * 
 * 1.创建请求实例，并将实例发送给管理工人线程的类
 * 
 * @author lxb
 *
 */
public class ClientThread extends Thread {

	private final Channel channel;
	private static final Random random = new Random();

	private volatile boolean terminated = false; // 停止请求标志

	public ClientThread(String name, Channel channel) {
		super(name);
		this.channel = channel;
	}

	public void run() {
		try {
			for (int i = 0; !terminated; i++) {
				try {
					Request request = new Request(getName(), i);
					channel.putRequest(request);
					Thread.sleep(random.nextInt(1000));
				} catch (InterruptedException e) {
					terminated = true;
				}
			}
		} finally {
			System.out.println(Thread.currentThread().getName()
					+ " is terminated.");
		}
	}

	public void stopThread() {
		terminated = true;
		interrupt();
	}
}

3.请求对象：

package worker.thread.pattern;

import java.util.Random;

/**
 * 请求实体类
 * @author lxb
 *
 */
public class Request {

	private final String name; //  
    private final int number;  // 
    private static final Random random = new Random();
    public Request(String name, int number) {
        this.name = name;
        this.number = number;
    }
    public void execute() {
        System.out.println(Thread.currentThread().getName() + " executes " + this);
        try {
            Thread.sleep(random.nextInt(1000));
        } catch (InterruptedException e) {
        }
    }
    public String toString() {
        return "[ Request from " + name + " No." + number + " ]";
    }
}

4.请求队列与工人线程管理类：

package worker.thread.pattern;

/**
 * 用来接受客户端线程发来的请求、将请求传递给工人线程，所以至少需要以下数据结构：
 * 1.一个队列来保存客户端发来的请求，还必须提供两个接口，一个putRequest保存请求， 另一个是取出请求takeRequest
 * 2.线程池来管理各个工人线程,这个池可以是一个线程数组，数组大小可自定义
 * 
 * @author lxb
 *
 */
public class Channel {

	private static final int MAX_REQUEST = 100; // 假设最大的请求队列值

	private final Request[] requestQueue; // 保存的请求队列

	private int tail;
	private int head;
	private int count; // 请求队列中的请求数量

	private final WorkerThread[] threadPool; // 工人线程池

	public Channel(int threads) {

		this.requestQueue = new Request[MAX_REQUEST];
		this.head = 0;
		this.count = 0;
		this.tail = 0;
		threadPool = new WorkerThread[threads];

		for (int i = 0; i < threadPool.length; i++) {
			 threadPool[i] = new WorkerThread("Worker-" + i, this);
		}
	}
	
	/**
	 * 开启工作线程
	 */
	public void startWorkers() {
		for (int i = 0; i < threadPool.length; i++) {
			threadPool[i].start();
		}
	}
	
	public void stopAllWorkers(){
		for(int i=0;i= requestQueue.length) {
			wait();
		}

		requestQueue[tail] = request;

		tail = (tail + 1) % requestQueue.length;

		count++;

		notifyAll();
	}

	public synchronized Request takeRequest() throws InterruptedException {
		while (count <= 0) {
			wait();
		}

		Request request = requestQueue[head];
		head = (head + 1) % requestQueue.length;

		count--;
		notifyAll();
		return request;
	}

}

5工人线程：

package worker.thread.pattern;

/**
 * 工作线程，处理客户端发来的具体的工作请求
 * @author lxb
 *
 */
public class WorkerThread extends Thread{

	private final Channel channel;
	private volatile boolean terminated = false;	//停止请求标志
	
	public WorkerThread(String name,Channel channel){
		super(name);
		this.channel = channel;
	}
	
	public void run() {
        try {
            while (!terminated) {
                try {                                           
                    Request request = channel.takeRequest();    
                    request.execute();                          
                } catch (InterruptedException e) {
                    terminated = true;
                }                                               
            }
        } finally {
            System.out.println(Thread.currentThread().getName() + " is terminated.");
        }
    }
    public void stopThread() {
        terminated = true;
        interrupt();
    }
}