加深对AQS原理的理解示例一:实现一个独占锁
/** *@Desc * 这个自定义的独占锁 只是一个简单的版本,非常粗糙,只为了加深对AQS原理理解。但还有一些列问题有待解决,比如锁的重入,锁不允许被其他线程中断等! *@Author zhangfengshi *@Date 2021/4/1 7:24 下午 *@Version 1.0 */ public class MutiLock implements Lock { public class Sync extends AbstractQueuedSynchronizer{ //是否处于独占状态 @Override public boolean isHeldExclusively(){ return getState()==1;//访问或修改同步状态 } //获取锁 @Override public boolean tryAcquire(int arg){ if(compareAndSetState(0,1)){ //设置当前线程拥有独占访问权 setExclusiveOwnerThread(Thread.currentThread()); return true; } return false; } //释放锁 @Override public boolean tryRelease(int arg){ //已经释放就抛异常 if(getState()==0){ throw new IllegalMonitorStateException(); } setExclusiveOwnerThread(null); setState(0); return true; } public Condition newCondition(){ return new ConditionObject(); } } public Sync sync=new Sync(); @Override public void lock() { sync.acquire(1); } @Override public void lockInterruptibly() throws InterruptedException { sync.acquireInterruptibly(1); } @Override public boolean tryLock() { return sync.tryAcquire(1); } @Override public boolean tryLock(long time, TimeUnit unit) throws InterruptedException { return sync.tryAcquireNanos(1, unit.toNanos(time)); } @Override public void unlock() { sync.tryRelease(1); } @Override public Condition newCondition() { return sync.newCondition(); } public boolean isLock(){ return sync.isHeldExclusively(); } }