《图解java多线程设计模式》中的 WorkerThread 模式

Channel：接收工作请求并将工作请求交给工人线程的类

public class Channel {
    private static final int MAX_REQUEST = 100;
    private final Request[] requestsQueue;
    private int tail;
    private int head;
    private int count;
    private final WorkerThread[] threadPool;

    public Channel(int threads){
        this.requestsQueue = new Request[MAX_REQUEST];
        this.head = 0;
        this.tail = 0;
        this.count = 0;

        threadPool = new WorkerThread[threads];
        for (int i = 0; i < threadPool.length;i++){
            threadPool[i] = new WorkerThread("worker- " + i,this);
        }
    }
    public void startWorkers(){
        for (int i = 0;i < threadPool.length;i++){
            threadPool[i].start();
        }
    }
    public synchronized void putRequest(Request request){
        while (count >= requestsQueue.length){
            try {
                wait();
            }catch (InterruptedException e){

            }
        }
        requestsQueue[tail] =request;
        tail = (tail + 1) % requestsQueue.length;
        count++;
        notifyAll();
    }
    public synchronized Request takeRequest(){
        while (count <= 0){
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        Request request = requestsQueue[head];
        head = (head + 1) %requestsQueue.length;
        count--;
        notifyAll();
        return request;
    }

}

ClientThread：表示发出工作请求的线程的类

public class ClientThread extends Thread{
    private final Channel channel;
    private static final Random radom = new Random();
    public ClientThread(String name,Channel channel){
        super(name);
        this.channel = channel;
    }
    public void run(){
        try {
            for (int i = 0;true;i++){
                Request request = new Request(getName(),i);
                channel.putRequest(request);
                Thread.sleep(radom.nextInt(1000));
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

Main：启动类

public class Main {
    public static void main(String[] args) {
        Channel channel = new Channel(5);
        channel.startWorkers();
        new ClientThread("aliex",channel).start();
        new ClientThread("bobby",channel).start();
        new ClientThread("chrix",channel).start();
    }
}

Request：表示工作请求的类

public class Request extends Thread{
    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 excute(){
        System.out.println(Thread.currentThread().getName() + " executes " + this);
        try {
            Thread.sleep(random.nextInt(1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    public String toString(){
        return " [ Request from" + name + " No. " + number + " ] ";
    }
}

WorkerThread：表示工人线程的类

public class WorkerThread extends Thread{
    private final Channel channel;
    public WorkerThread(String name,Channel channel){
        super(name);
        this.channel = channel;
    }
    public void run(){
        while (true){
            Request request = channel.takeRequest();
            request.excute();
        }
    }
}