docs: public void init(BaseField field, BaseField fldSource, DateTimeField fldStartDate, int lYears, int lMonths, int lDays, boolean bCalcIfNull)
      {
          super.init(field, fldSource, null, true, false);
          m_lYears = lYears;
          m_lMonths = lMonths;
          m_lDays = lDays;
          m_fldStartDate = fldStartDate;
          m_bCalcIfNull = bCalcIfNull;
      }