final boolean nonfairTryAcquire(int acquires) {
    final Thread current = Thread.currentThread();
    int c = getState();
    if (c == 0) { // 0 表示锁可用
        if (compareAndSetState(0, acquires)) { // CAS获取相应数量的锁
            setExclusiveOwnerThread(current); // 记录当前线程为占用排他锁的线程，用以让该线程可以重入地再次获取
            return true;
        }
    }
    else if (current == getExclusiveOwnerThread()) { // 允许占有排他锁的线程重入
        int nextc = c + acquires;
        if (nextc < 0) // overflow
            throw new Error("Maximum lock count exceeded");
        setState(nextc); // 更新锁被获取的数量
        return true;
    }
    return false;
}