AQS

小咪咪 2023-06-06 12:23 14阅读 0赞

照马士兵写的一个AQS类

package com.cocurrent.aqs;
    
    
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.AbstractQueuedSynchronizer;
    import java.util.concurrent.locks.Condition;
    import java.util.concurrent.locks.Lock;
    
    /**
     * @Author : WeiYaBo
     * @Description :
     * @Date : Created in 20:13 2019/10/11
     * @Modified By:
     */
    public class MLock implements Lock {
    
        private Sync sync = new Sync();
    
        @Override
        public void lock() {
            sync.acquire(1);
        }
    
        @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 void unlock() {
            sync.release(1);
        }
    
        @Override
        public Condition newCondition() {
            return null;
        }
    
        private class Sync extends AbstractQueuedSynchronizer {
            @Override
            protected boolean tryAcquire(int arg) {
                assert arg == 1;
                if (compareAndSetState(0, 1)) {
                    setExclusiveOwnerThread(Thread.currentThread());
                    return true;
                }
                return false;
            }
    
            @Override
            protected boolean tryRelease(int arg) {
                assert arg == 1;
                if (!isHeldExclusively()) {
                    throw new IllegalMonitorStateException();
                }
                setExclusiveOwnerThread(null);
                setState(0);
                return true;
            }
    
            @Override
            protected boolean isHeldExclusively() {
                return getExclusiveOwnerThread() == Thread.currentThread();
            }
        }
    }

ReentrantLock内也是继承了AQS重写了tryAcquire，tryRelease，isHeldExclusively三个方法

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