code: private static Term getUpperTerm(String upperName) {
          String text;
          if (upperName == null) {
              text = "\uFFFF";
          } else {
              text = upperName;
          }
          return new Term(FieldNames.LOCAL_NAME, text);
      }
docs: Creates a {@link Term} for the upper bound local name.
  
  @param upperName the upper bound local name.
  @return a {@link Term} for the upper bound local name.