docs: private void computeComparableValue() {
      recomputeComparableSortValue = false;
      try {
        int type = getCompareValueType();
        switch (type) {
        case 0:
          comparableSortValue = getCompareValue0();
          break;
        case 1:
          comparableSortValue = getCompareValue1();
          break;
        case 2:
          comparableSortValue = getCompareValue2();
          break;
        default:
          comparableSortValue = null;
          break;
        }
      } catch (IOException e) {
        log.debug(e);
        comparableSortValue = null;
      }
    }