* @return the stripe that the passed key corresponds to
   */
  public abstract L get(Object key);

  /**
   * Returns the stripe at the specified index. Valid indexes are 0, inclusively, to {@code size()},
   * exclusively.
   *
   * @param index the index of the stripe to return; must be in {@code [0...size())}
   * @return the stripe at the specified index
   */