fila node

package filas;

public class listaNode {

     Node front = null;
     Node back = null;

     public void enqueue(Node i) {
         if(front == null && back == null) {
             front = back = i;
         }else {
             back.setNext(i);
             i.setPrevious(back);
             back = i;
         }
     }

     public void dequeue() {
         if(front == null && back == null) {
             System.out.println("Lista vazia!!!!");
         }else {
             front = front.getNext();
             front.setPrevious(null);
         }
     }
}

//fila

package filas;

public class lista {
    int front = 0;
    int back = 0;
    int[] queue;
    int aux = 0;

    public lista() {
        queue = new int[4];

    }

    public void enqueue(int info) {
        if (back == 0) {
            queue[back] = info;
            back++;

            if (back == queue.length) {
                back = 0;
            }
        } else if (back == front) {
            System.out.println("Lista cheia!!!!!!");
        } else {
            queue[back] = info;
            back++;
        }
    }

    public int dequeue() {

        if (front == queue.length) {
            front = 0;
        } else if (front > back) {
            System.out.println("Lisa cheia!!!");

        } else {
            queue[front] = aux;
            queue[front] = 0;
            front++;
        }

        return aux;

    }
}

//
package filas;

public class Node {

    private int info;
    private Node next = null;
    private Node previous = null;

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }

    public Node getPrevious() {
        return previous;
    }

    public void setPrevious(Node previous) {
        this.previous = previous;
    }

    public int getInfo() {
        return info;
    }

    public void setInfo(int info) {
        this.info = info;
    }

}