public CVBuffer() 
{
 
    this(DefaultChannelCapacity.get());
}

 public CVBuffer(int cap) 
{
 
    array = new Object[cap];
    mutex = new Mutex();
    notFull = new CondVar(mutex);
    notEmpty = new CondVar(mutex);
}

 public int capacity() 
{
 return array.length;
}

 public boolean offer(Object x,
    long msecs) throws InterruptedException 
{
    mutex.acquire();
    try {
      if (count == array.length) {
        notFull.timedwait(msecs);
        if (count == array.length)
          return false;
      }
      array[putPtr] = x;
      putPtr = (putPtr + 1) % array.length;
      ++count;
      notEmpty.signal();
      return true;
    }
    finally {
      mutex.release();
    }
}

 public Object peek() 
{
    try {
      mutex.acquire();
      try {
        if (count == 0) 
          return null;
        else
          return array[takePtr];
      }
      finally {
        mutex.release();
      }
    }
    catch (InterruptedException ex) {
      Thread.currentThread().interrupt();
      return null;
    }
}

 public Object poll(long msecs) throws InterruptedException 
{
    Object x = null;
    mutex.acquire();
    try {
      if (count == 0) {
        notEmpty.timedwait(msecs);
        if (count == 0)
          return null;
      }
      x = array[takePtr];
      array[takePtr] = null;
      takePtr = (takePtr + 1) % array.length;
      --count;
      notFull.signal();
    }
    finally {
      mutex.release();
    }
    return x;
}

 public  void put(Object x) throws InterruptedException 
{
    mutex.acquire();
    try {
      while (count == array.length) {
        notFull.await();
      }
      array[putPtr] = x;
      putPtr = (putPtr + 1) % array.length;
      ++count;
      notEmpty.signal();
    }
    finally {
      mutex.release();
    }
}

 public Object take() throws InterruptedException 
{
    Object x = null;
    mutex.acquire();
    try {
      while (count == 0) {
        notEmpty.await();
      }
      x = array[takePtr];
      array[takePtr] = null;
      takePtr = (takePtr + 1) % array.length;
      --count;
      notFull.signal();
    }
    finally {
      mutex.release();
    }
    return x;
}