public DailyTimeIntervalScheduleBuilder onDaysOfTheWeek(Set<Integer> onDaysOfWeek){
  if (onDaysOfWeek == null || onDaysOfWeek.size() == 0)   throw new IllegalArgumentException("Days of week must be an non-empty set.");
  for (  Integer day : onDaysOfWeek)   if (!ALL_DAYS_OF_THE_WEEK.contains(day))   throw new IllegalArgumentException("Invalid value for day of week: " + day);
  this.daysOfWeek=onDaysOfWeek;
  return this;
}

public DailyTimeIntervalScheduleBuilder onDaysOfTheWeek ( Set < Integer > onDaysOfWeek ) { if ( onDaysOfWeek == null || onDaysOfWeek . size ( ) == 0 ) throw new IllegalArgumentException ( "Days of week must be an non-empty set." ) ; for ( Integer day : onDaysOfWeek ) if ( ! ALL_DAYS_OF_THE_WEEK . contains ( day ) ) throw new IllegalArgumentException ( "Invalid value for day of week: " + day ) ; this . daysOfWeek = onDaysOfWeek ; return this ; }
set the trigger to fire on the given days of the week .
