class BlockingQueue<T>
{
    T[] contents;
    int capacity;

    public BlockingQueue(int capacity)
    {
        contents = (T[]) new Object[capacity];
        this.capacity = capacity;
    }

    public synchronized int getCount()
    {
        for (int i = 0; i < capacity; i++)
        {
            if(contents[i] == null)
                return i;
        }

        return 0;
    }

    public synchronized void enqueue(T item) throws InterruptedException
    {
        int count = this.getCount();
        while (count == this.capacity)
            wait();

        contents[count] = item;
        notifyAll();
    }

    public synchronized T dequeue() throws InterruptedException
    {
        int count = this.getCount();
        while (count == 0)
            wait();

        T item = contents[count];

        contents[count] = null;

        notifyAll();

        return item;
    }
}