一个可重入Lock的实现

最新推荐文章于 2024-03-31 17:11:08 发布

转载最新推荐文章于 2024-03-31 17:11:08 发布 · 260 阅读

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本文深入探讨了自定义实现Lock接口的方法，通过一个具体的MyLock类示例，详细讲解了如何使用synchronized关键字和wait/notify机制来控制线程同步，确保资源的正确访问。

好好想想：：：

public class MyLock implements Lock{

    private boolean isLocked = false;

    private Thread lockBy = null;
    private int lockCount = 0;

    @Override
    public synchronized void lock() {
       Thread currentThread  = Thread.currentThread();
        while(isLocked &&  currentThread != lockBy)
            try{
                wait();
            }catch(InterruptedException e){
               e.printStackTrace();
            }
        isLocked = true;
        lockBy =  Thread.currentThread();
        lockCount ++;
    }

    @Override
    public void lockInterruptibly() throws InterruptedException {

    }

    @Override
    public boolean tryLock() {
        return false;
    }

    @Override
    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
        return false;
    }

    @Override
    public synchronized void unlock() {
        if(lockBy == Thread.currentThread()){
            lockCount --;
            if(lockCount == 0){
                notify();
                isLocked = false;

            }
        }


    }

    @Override
    public Condition newCondition() {
        return null;
    }
}

public class Demo9 {
    MyLock lock = new MyLock();
    public void a(){
        lock.lock();
        System.out.println("a");
        b();
        lock.unlock();
    }
    public void b(){
        lock.lock();
        System.out.println("b");
        lock.unlock();
    }

    public  static void main(String[] args){
        Demo9 demo9 = new Demo9();
        new Thread(new Runnable() {
            @Override
            public void run() {
                demo9.a();
            }
        }).start();
    }

}