code: public CaseInsensitiveString getDirectParentName() {
          String stringPath = path();
          if (stringPath == null) {
              return null;
          }
          int index = stringPath.lastIndexOf(DELIMITER);
          return index == -1 ? path : new CaseInsensitiveString(stringPath.substring(index + 1, stringPath.length()));
      }
docs: cache parent name if required (like ancestor). currently used only for UI.