public class NodeQueue<E> implements QueueADT<E> {

	protected Node<E> head;
	protected Node<E> tail;
	protected int size;

	public NodeQueue(){
		head=null;
		tail=null;
		size=0;
	}

	public void enqueue(E element) {
		Node<E> v = new Node<E>(element,tail);
		tail = v;
		size++;
	}


	public E dequeue() {
		if (isEmpty()) throw new
		EmptyQueueException("The Queue is empty. Cannot dequeue from Queue.");
		E deq = head.getElement();
		head = head.getNext();
		size--;
		return deq;
	}


	public E front() {
		if (isEmpty()) throw new
		EmptyQueueException ("The Queue is empty. Can't show the front element.");
		return head.getElement();
	}


	public int size() {
		return size;
	}


	public boolean isEmpty() {
		return head==null;
	}

}