public class LinkedListQueue<E>implements Queue<E>{
    private class Node{
       public E e;
       public Node next;
       public Node(E e,Node next){
              this.e=e;
              this.next=next; 
           }
       public  Node(){
             this(null,null);
        }
       public Node(E e){
            this(e,null);
       }
     private Node head;
     private Node tail;
     private int size;
     public LinkedListQueue(){
           head=null;
           tail=null;
           size=0;
       }
       public void enqueue(E e){
             if(tail == null){
                tail=new Node(e)'
                head=tail;
             }else{
                 tail.next=new Node(e);
                 tail=tail.next;
             }
         size++;
       }
        public E dequeue(){
             if(idEmpty()){
                 throw new IllegalArgumentException("Cannot dequeue from anempty queue");
             }
             Node returnNode=head;
             head=head.next;
             returnNode.next=null;
            if(head == null){
                 tail=null;
            }
           size--;
           return returnNode.e;
         }
          
       public E getFront(){
            if(isEmpty()){
                  throw new IllegalArgumentException("Cannot dequeue from anempty queue");
            }
            
       }    
    }
}