Remove object form list using method with parameter

Question

Im trying to remove a object from a list using a method with a specific index that I wish to remove. The tricky part here is that this list is a doublelinkedlist and when I remove a node from it, the next and previous pointer needs to be redirected to the correct nodes. Here is what I got so far, but the code does not seem to redirect the pointers correctly, I would appriciate any inputs!

 private static final class Node<T>      
  {
    private T value;
    private Node<T> previous, next;

    private Node(T value, Node<T> previous, Node<T> next) // constructor
    {
      this.value = value;
      this.previous = previous;
      this.next = next;
    }
  }

  private Node<T> head;         // first in the list
  private Node<T> tale;         // last in the list






public T remove(int index)   { 
      indexcontrol(index); // checks if legal index

      Node<T> q, p = null;

      if(index == 0)
      {
          q = head;
          head = head.next;
      }

      else
      {
          p = findNode(index-1); // finds the nodes value on place index
          q = p.next;

          p.next= q.next;
      }

      if ( q== tale) tale = p;

      T value = q.value;
      q.value = null;

      q.next = null;

      return value;

  }

Answer 1

You need to assign the previous and next pointer to the correct node.

public T remove (int index){
    if (index==0){
        //remove head
    }else if (index == size){
        //remove tail
    }
    else {
        Node<T> p = null;
        Node<T> q = null;
        Node<T> r = null;
        p = findNode(index-1); // finds the nodes previous to the node that needs to be removed
        q = p.next; //q is the node you want to remove
        r = q.next; //r is the node next to the node you want to remove

        p.next = r;
        r.previous = p;

        //you can explicitly delete the node, but GC will collect anyway. 
        q.next = null;
        q.previous = null;
        T value = q.value;
        q.value = null;
        return value;
    }
}

Answer 2

You can see the source code of java.util.LinkedList, then you will know how to implement it.

Answer 3

It seems that in else statement you change only one pointer, when you should be changing two of them. Should be something like this:

prevNode.next = origNode.next;
nextNode.prev = origNode.prev;