public class ArrayQueue<T> implements Queue<T> {
	private int capacity;
	private Object[] queue;
	private int ini = 0;
	private int prox = 0;

	public ArrayQueue(int capacity) {
		this.capacity = capacity;
		queue = new Object[capacity + 1];
	}

	@Override
	public void enqueue(T obj) throws QueueFullException {
		if (isFull()) {
			throw new QueueFullException();
		}

		queue[prox] = obj;
		prox = (prox + 1) % queue.length;
	}

	@Override
	public T dequeue() throws QueueEmptyException {
		if (isEmpty()) {
			throw new QueueEmptyException();
		}
		Object dequeued_obj = queue[ini];
		queue[ini] = null;
		ini = (ini + 1) % queue.length;
		return (T) dequeued_obj;
	}

	@Override
	public int size() {
		if (prox >= ini) {
			return prox - ini;
		} else {
			return queue.length - (ini - prox);
		}
	}

	@Override
	public boolean isEmpty() {
		return size() == 0;
	}

	@Override
	public boolean isFull() {
		return size() == capacity;
	}

	@Override
	public T front() throws QueueEmptyException {
		if (isEmpty()) {
			throw new QueueEmptyException();
		}

		return (T) queue[ini];
	}

	@Override
	public void empty() {
		while (!isEmpty()) {
			try {
				dequeue();
			} catch (QueueEmptyException e) {
				e.printStackTrace();
			}
		}
	}
}