package sequence.utility;

import exceptions.InvalidPositionException;
import position.Position;

/**
 * A simple node class for a doubly-linked list.  Each DNode has a
 * reference to a stored element, a previous node, and a next node.
 * 
 * @author Roberto Tamassia
 */
//Copyright (c) 2003 Brown University, Providence, RI
//Additional modifications and methods by xgiovio

public class DNodeIndex<E> implements Position<E> {
  private DNodeIndex<E> prev = null;
  private DNodeIndex<E> next = null;
  private E element = null;
  private int index = -1;


  public DNodeIndex(DNodeIndex<E> newPrev, DNodeIndex<E> newNext, E elem, int in_idex) {
    prev = newPrev;
    next = newNext;
    element = elem;
    index = in_idex;
  }
    public DNodeIndex(DNodeIndex<E> newPrev, DNodeIndex<E> newNext, E elem) {
        prev = newPrev;
        next = newNext;
        element = elem;
    }

  public E element() throws InvalidPositionException {
    if ((prev == null) && (next == null))
      throw new InvalidPositionException("Position is not in a list!");
    return element;
  }

  public DNodeIndex<E> getNext() { return next; }
  public DNodeIndex<E> getPrev() { return prev; }

  public void setNext(DNodeIndex<E> newNext) { next = newNext; }
  public void setPrev(DNodeIndex<E> newPrev) { prev = newPrev; }
  public void setElement(E newElement) { element = newElement; }

    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }
}