/** Source code example for "A Practical Introduction to Data
    Structures and Algorithm Analysis, 3rd Edition (Java)" 
    by Clifford A. Shaffer
    Copyright 2008-2011 by Clifford A. Shaffer
*/

/** List ADT */
public interface List<E> {
  /** Remove all contents from the list, so it is once again
      empty. Client is responsible for reclaiming storage
      used by the list elements. */
  public void clear();

  /** Insert an element at the current location. The client
      must ensure that the list's capacity is not exceeded.   
      @param item The element to be inserted. */
  public void insert(E item);

  /** Append an element at the end of the list. The client
      must ensure that the list's capacity is not exceeded.   
      @param item The element to be appended. */
  public void append(E item);

  /** Remove and return the current element.
      @return The element that was removed. */
  public E remove();

  /** Set the current position to the start of the list */
  public void moveToStart();

  /** Set the current position to the end of the list */
  public void moveToEnd();

  /** Move the current position one step left. No change
      if already at beginning. */
  public void prev();

  /** Move the current position one step right. No change
      if already at end. */
  public void next();

  /** @return The number of elements in the list. */
  public int length();

  /** @return The position of the current element. */
  public int currPos();

  /** Set current position.
      @param pos The position to make current. */
  public void moveToPos(int pos);

  /** @return The current element. */
  public E getValue();
}