code: public void addOrderBy(String fieldName, boolean sortAscending)
      {
          if (fieldName != null)
          {
              _getOrderby().add(new FieldHelper(fieldName, sortAscending));
          }
      }
docs: Adds a field for orderBy
  @param  fieldName the field name to be used
  @param  sortAscending true for ASCENDING, false for DESCENDING
  @deprecated use QueryByCriteria#addOrderBy