/**
 * A simple Node class for implementing linked structures.  An
 * interesting design question is whether we permit setting of
 * fields (we could instead require the client to create a new
 * replacement node).
 *
 * @author Samuel A. Rebelsky
 * @version 1.0 of April 1999
 */
public class Node {
  // +--------+--------------------------------------------------
  // | Fields |
  // +--------+

  /** The contents of the current node. */
  protected Object contents;

  /** The next node in the list.  Set to null for empty lists. */
  protected Node next;


  // +--------------+--------------------------------------------
  // | Constructors |
  // +--------------+

  /**
   * Create a new node with specified contents and no next
   * element.
   */
  public Node(Object contents) {
    this(contents,null);
  } // Node(Object)

  /**
   * Create a new node with specified contents and specified
   * next element.  The next element can be null.
   */
  public Node(Object contents, Node next) {
    this.contents = contents;
    this.next = next;
  } // Node(Object,Node)


  // +-----------+-----------------------------------------------
  // | Accessors |
  // +-----------+

  /**
   * Get the contents of the current node.
   */
  public Object getContents() {
    return this.contents;
  } // getContents()

  /**
   * Get the next node.
   */
  public Node getNext() {
    return this.next;
  } // getNext()


  // +-----------+-----------------------------------------------
  // | Modifiers |
  // +-----------+

  /**
   * Set the contents of the current node.  Returns the old contents.
   */
  public Object setContents(Object newContents) {
    Object oldContents = this.contents;
    this.contents = newContents;
    return oldContents;
  } // setContents(Object)
 
  /**
   * Set the next node.  Returns the old next node.
   */
  public Object setNext(Node newNext) {
    Object oldNext = this.next;
    this.next = newNext;
    return oldNext;
  } // setNext(Node)

} // class Node