GUC-13 生產者消費者案例

 

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/*
 * 生產者消費者案例：
 */
public class TestProductorAndConsumerForLock {

    public static void main(String[] args) {
        Clerk clerk = new Clerk();

        Productor pro = new Productor(clerk);
        Consumer con = new Consumer(clerk);

        new Thread(pro, "生產者 A").start();
        new Thread(con, "消費者 B").start();

//         new Thread(pro, "生產者 C").start();
//         new Thread(con, "消費者 D").start();
    }

}

class Clerk {
    private int product = 0;

    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();

    // 進貨
    public void get() {
        lock.lock();

        try {
            if (product >= 1) { // 爲了不虛假喚醒，應該老是使用在循環中。
                System.out.println("產品已滿！");

                try {
                    condition.await();
                } catch (InterruptedException e) {
                }

            }
            System.out.println(Thread.currentThread().getName() + " : "
                    + ++product);

            condition.signalAll();
        } finally {
            lock.unlock();
        }

    }

    // 賣貨
    public void sale() {
        lock.lock();

        try {
            if (product <= 0) {
                System.out.println("缺貨！");

                try {
                    condition.await();
                } catch (InterruptedException e) {
                }
            }

            System.out.println(Thread.currentThread().getName() + " : "
                    + --product);

            condition.signalAll();

        } finally {
            lock.unlock();
        }
    }
}

// 生產者
class Productor implements Runnable {

    private Clerk clerk;

    public Productor(Clerk clerk) {
        this.clerk = clerk;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            clerk.get();
        }
    }
}

// 消費者
class Consumer implements Runnable {

    private Clerk clerk;

    public Consumer(Clerk clerk) {
        this.clerk = clerk;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            clerk.sale();
        }
    }

}