code: public DailyTimeIntervalScheduleBuilder onDaysOfTheWeek (final Set <DayOfWeek> onDaysOfWeek)
    {
      ValueEnforcer.notEmpty (onDaysOfWeek, "OnDaysOfWeek");
  
      m_aDaysOfWeek = onDaysOfWeek;
      return this;
    }
docs: Set the trigger to fire on the given days of the week.
  
  @param onDaysOfWeek
  a Set containing the integers representing the days of the week, per
  the values 1-7 as defined by {@link Calendar#SUNDAY} -
  {@link Calendar#SATURDAY}.
  @return the updated DailyTimeIntervalScheduleBuilder