/**
 * A doubly-linked Node.  Each node contains a data element and pointers
 * to the node before and after it in the linked list.
 *
 * @author Zach Tomaszewski
 */
public class DLNode<E> {

  private E data;
  private DLNode<E> next;
  private DLNode<E> prev;

  /** Constructs a new node with the given data and links. */
  public DLNode(DLNode<E> prev, E data, DLNode<E> next) {
    this.data = data;
    this.prev = prev;
    this.next = next;
  }

  /**
   * Construct a new node with the given data.
   * Next and previous links will be null.
   */
  public DLNode(E data) {
    this(null, data, null);
  }

  /** Returns the item currently stored in this node. */
  public E getData() {
    return data;
  }

  /** Overwrites the item stored in this Node with the given data item. */
  public void setData(E data) {
    this.data = data;
  }

  /**
   * Returns the Node after this one in the linked list structure.
   * If there is no next Node, returns null.
   */
  public DLNode<E> getNext() {
    return next;
  }

  /** Causes this Node to point to the given next Node. */
  public void setNext(DLNode<E> next) {
    this.next = next;
  }

  /**
   * Return the Node before this one in the linked list, or null
   * if there is no such node.
   */
  public DLNode<E> getPrevious() {
    return prev;
  }

  /**
   * Sets the given prev node as the node before this on in the linked list.
   */
  public void setPrevious(DLNode<E> prev) {
    this.prev = prev;
  }
}