package queues;

public interface Queue<E> {
	
	/**
	 * Returns the number of elements in the queue
	 * @return number of elements in the queue
	 */
	public int size();
	
	/**
	 * Returns whether the queue is empty
	 * @return true if queue is empty, false otherwise
	 */
	public boolean isEmpty();
	
	/**
	 * Inspects the element at the front of the queue
	 * @return element at the front of the queue
	 * @exception EmptyQueueException if the queue is empty
	 */
	public E front() throws EmptyQueueException;
	
	/**
	 * Inserts an element at the rear of the queue
	 * @param element new element to be inserted
	 */
	public void enqueue (E element);
	
	/**
	 * Removes the element at the front of the queue
	 * @return element removed
	 * @exception EmptyQueueException if the queue is empty
	 */
	public E dequeue() throws EmptyQueueException;
	 

}