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生产者消费者案例的lock写法

其中涉及到了Condition的用法，简答的介绍一下：

1.Condition接口描述了可能会与锁相关的条件变量，这些变量在用法上与使用Object.wait访问的隐式监视器类似，但提供了更强大的功能。需要特别之处的是，单个lock可能会与多个Condition对象关联，为了避免兼容性问题，Condition方法的名称与对应的Object版本中的不同。

2.在Condition对象中，与wait,notify,notifyAll方法对应的分别是await,signal,signalAll

3.Condition实例实质上被绑定到一个锁上。要为特定的Lock实例获得Condition，使用newCondition()方法即可。

具体代码：

public class TestProductorAndCustomerForLock {

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

        new Thread(productor,"productor A").start();
        new Thread(productor,"productor B").start();
        new Thread(customer,"customer A").start();
        new Thread(customer,"customer B").start();
    }
}

class Clerk {
    private int productor = 0;
    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();

    //进货
    public  void get() {
        lock.lock();
        try {
            while (productor >= 1) {
                System.out.println("产品已满！");
                try {
                    condition.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println(Thread.currentThread().getName() + ":" + ++productor);
            condition.signalAll();
        }finally {
            lock.unlock();
        }
    }

    //卖货
    public  void sale() {
        lock.lock();
        try {
            while (productor <= 0) {
                System.out.println("缺货！");
                try {
                    condition.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println(Thread.currentThread().getName() + ":" + --productor);
            condition.signalAll();

        }finally {
            lock.unlock();
        }

    }
}


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();
        }
    }
}

class Customer implements Runnable{
    private Clerk clerk;

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

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

运行结果：