BoundedBlockingQueue

BoundedBlockingQueue.java

public class BoundedBlockingQueue {
  private Deque<Integer> queue;
  private Semaphore enqueue;
  private Semaphore dequeue;

  public BoundedBlockingQueue(int capacity) {
    queue = new ConcurrentLinkedDeque<>();
    enqueue = new Semaphore(capacity);
    dequeue = new Semaphore(0);
  }

  public void enqueue(int element) throws InterruptedException {
    enqueue.acquire();
    queue.add(element);
    dequeue.release();
  }

  public int dequeue() throws InterruptedException {
    dequeue.acquire();
    int val = queue.poll();
    enqueue.release();
    return val;
  }

  public int size() {
    return queue.size();
  }
}