本文是看视频学习笔记,若有错误请指正!
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: