Queue.java

/**
 * This is the Queue interface for the QueueList class.
 * @author Wei Zhong Tee
 * @since 8 May 2020
 */
public interface Queue<E>{



	/**	Returns true if the stack is empty; otherwise false
		@return true is stack is empty otherwise false
	*/
	public boolean isEmpty();

	/** Returns the object at the front of the queue without removing it
		@return the object at the front of the queue
		@throws NoSuchElementException
	*/
	public E front();

	/** Returns the object at the front of the queue and removes it
		so stack is one smaller
		@return the object at the front of the queue
		@throws NoSuchElementException
	*/
	public E dequeue();


	/** Pushes an item onto the rear of the queue
		@param it The object to be inserted at the rear
	*/
	public void enqueue(E it);


	/** Dumps the queue - clears it of its contents
	*/
	public void clear();


	/** Returns the number of elements in the queue
		@return size - the number of elements on the queue
	*/
	public int size();
}