how can I stop a specific thead in semaphore in java?

Question

I have implemented producer and consumer problem with semaphore. I need a way that when there is no product for consuming , the current thread wait until a producer produce a product. please guide me.

Answer 1

Check out Java's BlockingQueue, it already supports this behavior.

Code taken from the JavaDoc linked above, as an example:

class Producer implements Runnable {
    private final BlockingQueue queue;
    Producer(BlockingQueue q) { queue = q; }
    public void run() {
        try {
           while (true) { queue.put(produce()); }
        } catch (InterruptedException ex) { ... handle ...}
      }
    Object produce() { ... }
}

class Consumer implements Runnable {
  private final BlockingQueue queue;
  Consumer(BlockingQueue q) { queue = q; }
  public void run() {
    try {
      while (true) { consume(queue.take()); }
    } catch (InterruptedException ex) { ... handle ...}
  }
  void consume(Object x) { ... }
}

class Setup {
  void main() {
    BlockingQueue q = new SomeQueueImplementation();
    Producer p = new Producer(q);
    Consumer c1 = new Consumer(q);
    Consumer c2 = new Consumer(q);
    new Thread(p).start();
    new Thread(c1).start();
    new Thread(c2).start();
  }
}