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//Copyright Standish, Willey, and Suchenek
//All rights reserved

package split;

/**
 *
 * @author suchenek
 */
public class QUEUE3<E> {
	List<E> front;
	List<E> rear; // points to the last element

	public void enqueue(E x)
	{
		cnt.incr();
                List<E> temp = new List<E>();
		temp.head = x;
		temp.tail = null;
                if(rear==null)
                {
                    front = temp;
                    rear = temp;
                }
                else
                {
                    rear.tail = temp;
                    rear = temp; //rear = rear.tail;
                }
	}

	public E dequeue()
	{
		cnt.incr();
                if (rear == null) return null; // queue is empty
                E toReturn = front.head;
		front = front.tail;
                if(front == null) rear = null; // dequeued the only element
                return toReturn;
	}


        public Boolean isEmpty()
    {
            return front == rear;
        }

            public void dump()
            {
                List i = front;
                System.out.print("Dump:");
                while (i!=null)
                {
                    System.out.print(i.head + " ");
                    i = i.tail;
               }
                System.out.println(" End Dump");
            }

        public QUEUE3<E> cloneAbstract()
//      Deep clone
	{
            QUEUE3<E> toReturn = new QUEUE3<E>();
            for (List<E> p = front; p !=null; p = p.tail)
            {
                toReturn.enqueue(p.head);
            }
            return toReturn;
        }

        public QUEUE3<E> clone()
//      Deep clone
	{
            QUEUE3<E> toReturn = new QUEUE3<E>();
            for (List<E> p = front; p != null; p = p.tail)
            {
                List<E> temp = new List<E> ();
                temp.head = p.head;
                temp.tail = null;
                if (toReturn.rear == null)
                {
                    toReturn.front = temp;
                    toReturn.rear = temp;
                }
                else
                {
                    toReturn.rear.tail = temp;
                    toReturn.rear = temp;
                }
            }
            return toReturn;
        }

}