public Unit getPrecision() {
    ensureParsed();
    Unit result = null;
    if (isPresent(fNanosecond)) {
      result = Unit.NANOSECONDS;
    }
    else if (isPresent(fSecond)) {
      result = Unit.SECOND;
    }
    else if (isPresent(fMinute)) {
      result = Unit.MINUTE;
    }
    else if (isPresent(fHour)) {
      result = Unit.HOUR;
    }
    else if (isPresent(fDay)) {
      result = Unit.DAY;
    }
    else if (isPresent(fMonth)) {
      result = Unit.MONTH;
    }
    else if (isPresent(fYear)) {
      result = Unit.YEAR;
    }
    return result;
  }