/**
   * Check if mission with give id exists in compare list.
   *
   * @param id the id of mission to check
   * @return true if mission exists, false otherwise
   */
  public static boolean exists(long id) {
    for (CompareItem item : ITEMS) {
      if (item.getMission().getId() == id) {
        return true;
      }
    }

    return false;
  }