tryRelease函数/

xhz

tryRelease函数/*
* Note that tryRelease and tryAcquire can be called by
* Conditions. So it is possible that their arguments contain
* both read and write holds that are all released during a
* condition wait and re-established in tryAcquire.
*/

protected final boolean tryRelease(int releases) {
    // 判断是否伪独占线程
    if (!isHeldExclusively())
        throw new IllegalMonitorStateException();
    // 计算释放资源后的写锁的数量
    int nextc = getState() - releases;
    boolean free = exclusiveCount(nextc) == 0; // 是否释放成功
    if (free)
        setExclusiveOwnerThread(null); // 设置独占线程为空
    setState(nextc); // 设置状态
    return free;
}
说明: 此函数用于释放写锁资源，首先会判断该线程是否为独占线程，若不为独占线程，则抛出异常，否则，计算释放资源后的写锁的数量，若为0，表示成功释放，资源不将被占用，否则，表示资源还被占用。其函数流程图如下。
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原文链接：https://pdai.tech/md/java/thread ... tReadWriteLock.html