java - getWaitQueueLength 抛出 IllegalArgumentException : Not owner

Question

我正在做并发问题作业。我有许多线程执行特定的操作，并且有一个方法决定这些线程何时可以访问资源。

所以我的类看起来像这样:

public class Boss extends ReentrantLock implements Runnable {

    Lock access = new ReentrantLock();
    Condition canTakeOff = access.newCondition();
    Condition canLand = access.newCondition();

    public void accessToLanding(){
            access.lock();
            try{
                if(getWaitQueueLength(canTakeOff) > 0){
                    canTakeOff.notifyAll();
                } else if {
                 /* some other cases */
                }
            } catch (InterruptedException e){
                e.printStackTrace();
            } finally {
                access.unlock();
            }
    }

    public void run(){
        accessToLanding();
    }

    /* Methods which are called by objects of a different class, 
    they are awaiting for the signal from accessToLanding.*/
}

我收到错误:

Exception in thread "Thread-0" java.lang.IllegalArgumentException: Not owner
at java.util.concurrent.locks.AbstractQueuedSynchronizer.getWaitQueueLength(AbstractQueuedSynchronizer.java:1789)
at java.util.concurrent.locks.ReentrantLock.getWaitQueueLength(ReentrantLock.java:720)

我检查了文档，它说当“给定条件与此锁无关”时， getWaitQueueLength 会抛出 IllegalArgumentException ，但根据我的理解，它与我的代码相关联。有人可以帮助我吗？

Answer 1

当你调用时

getWaitQueueLength(canTakeOff)

你正在打电话

this.getWaitQueueLength(canTakeOff)

其中this是您的Boss实例。尽管canTakeOff已声明有成员，但它并不属于 Boss，而是从access获取的条件

我认为您必须稍微更改上述行并使用

access.getWaitQueueLength(canTakeOff)

更多信息:Javadoc getWaitQueueLength throws IllegalArgumentException