多线程 多生产者 多消费者 交替生成不同食物 消费者交替消费不同食物

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/*
 * 多生产者     多消费者
 */
public class producer_consumer {
    public static void main(String[] args) {
        Product p = new Product();
        Thread t0 = new Thread(new Producer(p));
        Thread t1 = new Thread(new Producer(p));
        Thread t2 = new Thread(new Consumer(p));
        Thread t3 = new Thread(new Consumer(p));
        t0.start();
        t1.start();
        t2.start();
        t3.start();
    }
}

class Consumer implements Runnable {
    private Product p;

    public Consumer(Product p) {
        super();
        this.p = p;
    }

    @Override
    public void run() {
            p.get();
    }
}

class Producer implements Runnable {
    private Product p;

    public Producer(Product p) {
        super();
        this.p = p;
    }

    @Override
    public void run() {        
            p.set();
    }

}

class Product {
    private String name;
    private String color;
    boolean flag = false;

    public Product() {
        super();
    }

    private int pos;
    Lock l = new ReentrantLock();//创建一个锁对象
    Condition producer_c = l.newCondition();//创建一个生产者监视器
    Condition consumer_c = l.newCondition();//消费者监视器

    public void set() {

        while (true) {
            l.lock();//加上锁
            while (flag) {
                try {
                    producer_c.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            if (pos % 2 == 0) {
                this.setName("馒头");
                this.setColor("白色");
            } else {
                this.setName("玉米");
                this.setColor("黄色");
            }
            System.out.println(Thread.currentThread().getName()+"生产者生产============"+this.getName()+" *** "+this.getColor());
            pos++;
            flag = true;
            consumer_c.signal();//唤醒消费者
            l.unlock();//释放锁
        }
    }

    public void get() {
        while (true) {
            l.lock();
            while (!flag) {
                try {
                    consumer_c.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println(Thread.currentThread().getName() + "..消费者消费..."
                    + this.getName() + "===" + this.getColor());
            flag=false;
            producer_c.signal();//唤醒生产者
            l.unlock();
        }
    }

    public Product(String name, String color) {
        super();
        this.name = name;
        this.color = color;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

}