Start of week for locale using Joda-Time

user_39334 0
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How do you determine which day of the week is considered the “start” according to a given Locale using Joda-Time?

Point: Most countries use the international standard Monday as first day of week (!). A bunch others use Sunday (notably USA). Others apparently Saturday. Some apparently Wednesday?!

Wikipedia "Seven-day week"#Week_number

weekday calendar jodatime java
8 Answers

This is what I came up with. The startOfWeek will always be the start of a Sunday and the endOfweek will always be an end of a Saturday(Start a of Monday).

DateTime startOfWeek;
DateTime endOfWeek;
// make sure Sunday is the first day of the week, not Monday
if (dateTime.getDayOfWeek() == 7) {
    startOfWeek = dateTime.plusDays(1).weekOfWeekyear().roundFloorCopy().minusDays(1);
    endOfWeek = dateTime.plusDays(1).weekOfWeekyear().roundCeilingCopy().minusDays(1);
} else {
    startOfWeek = dateTime.weekOfWeekyear().roundFloorCopy().minusDays(1);
    endOfWeek = dateTime.weekOfWeekyear().roundCeilingCopy().minusDays(1);
}
user_57181070

Here is the Scala code to get start and end day of week dynamically.

Note:- Make sure start and end are in order for example when start day is Sunday then Monday is end day of week

def shiftWeeksBy(startDayOfWeek: Int, currentWeekDay: Int) : Int = (startDayOfWeek, currentWeekDay) match {
  case (s, c) if s <= c  | s == 1 => 0 //start day of week is Monday -OR- start day of week <= current week day
  case _ => 1
}

def getStartAndEndDays(initialTime: DateTime, startDayOfWeek: Int, endDayOfWeek: Int): (Option[DateTime], Option[DateTime]) = {
   val currentDateWeekDay = initialTime.dayOfWeek.get
   (Some(initialTime.minusWeeks(shiftWeeksBy(startDayOfWeek, currentDateWeekDay)).withDayOfWeek(startDayOfWeek).withTimeAtStartOfDay()),
       Some(initialTime.plusWeeks(shiftWeeksBy(currentDateWeekDay, endDayOfWeek)).withDayOfWeek(endDayOfWeek)))
}

Output:- For 5th Jan 2021 start day of week is Thursday and end day of week is Wednesday then week begins with 2020-12-31 and end with 2021-01-06.

scala> getStartAndEndDays(new DateTime("2021-01-05T00:00:00.000"), 4, 3)
res5: (Option[org.joda.time.DateTime], Option[org.joda.time.DateTime]) = (Some(2020-12-31T00:00:00.000+05:30),Some(2021-01-06T00:00:00.000+05:30))
user_35956180
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