code: public int compare(final T first, final T second) {
      if (first.equals(second)) return 0;
      else return first.size() - second.size();
    }
docs: <p>
  compare.
  </p>
  
  @param first a T object.
  @param second a T object.
  @return equals : 0,first less then second : -1 or small , first greate then second : 1 or big