code: public int elementCompareTo(final T element) {
          // Comparable API says throw NPE on null
          Validate.notNull(element, "Element is null");
          if (isAfter(element)) {
              return -1;
          } else if (isBefore(element)) {
              return 1;
          } else {
              return 0;
          }
      }
docs: <p>Checks where the specified element occurs relative to this range.</p>
  
  <p>The API is reminiscent of the Comparable interface returning {@code -1} if
  the element is before the range, {@code 0} if contained within the range and
  {@code 1} if the element is after the range. </p>
  
  @param element  the element to check for, not null
  @return -1, 0 or +1 depending on the element's location relative to the range