code: public DailyTimeIntervalScheduleBuilder withInterval (final int timeInterval, final EIntervalUnit unit)
    {
      if (unit == null ||
          !(unit.equals (EIntervalUnit.SECOND) || unit.equals (EIntervalUnit.MINUTE) || unit.equals (EIntervalUnit.HOUR)))
        throw new IllegalArgumentException ("Invalid repeat IntervalUnit (must be SECOND, MINUTE or HOUR).");
      _validateInterval (timeInterval);
      m_nInterval = timeInterval;
      m_eIntervalUnit = unit;
      return this;
    }
docs: Specify the time unit and interval for the Trigger to be produced.
  
  @param timeInterval
  the interval at which the trigger should repeat.
  @param unit
  the time unit (IntervalUnit) of the interval. The only intervals
  that are valid for this type of trigger are
  {@link EIntervalUnit#SECOND}, {@link EIntervalUnit#MINUTE}, and
  {@link EIntervalUnit#HOUR}.
  @return the updated DailyTimeIntervalScheduleBuilder
  @see IDailyTimeIntervalTrigger#getRepeatInterval()
  @see IDailyTimeIntervalTrigger#getRepeatIntervalUnit()