如何用同步，等待和通知的Java监视器替换Java Semaphore的获取和发布（全部）

Question

My code works with semaphores, but I want to make this work with Java monitors: wait, notify, notifyAll and synchronized instead of acquire and release. Can anyone tell me how I can do this?

public class Track {

    private final Semaphore mutex = new Semaphore(1,true);
    private final Semaphore use = new Semaphore(1,true);

    public Track(){}

    public void gebruikWissel(String v) throws InterruptedException
    {
        mutex.acquire();
        System.out.format("Trein %s maakt gebruik van de wissel", v);
        mutex.release();
    }

    public void useTrack() throws InterruptedException
    {
        use.acquire();
    }

    public void stopUseTrack()
    {
        use.release();
    }
}

Answer 1

you can do it using synchronized and a simple internal counter, eg:

private int counter;

public synchronized void useTrack() throws InterruptedException
{
    while(counter == 1) {
      wait();
    }
    counter++;
}

public synchronized void stopUseTrack()
{
    counter--;
    notifyAll();
}

UPDATE: didn't realize this was homework. well, i hope i get a good grade!

Answer 2

I don't think you can the way your class is structured. You can't even write a useTrack() or 'stopUseTrack()' method that use synchronization, for example.

It is more common for people to go from synchronization to semaphores. Why do you think you want to go in the opposite direction.