JodaTime equivalent of DateUtils.truncate()

Question

I have never used JodaTime before, but answering this question, How to get ordinal Weekdays in a Month.

I tried it and came up with this ugly code to unset all fiel

Answer 1

Use the withMillisOfDay() method to shorten the syntax.

DateTime startOfMonth = input.withDayOfMonth(1).withMillisOfDay(0);

Answer 2

Take a look at DateMidnight.

DateTime startOfMonth = new DateTime(new DateMidnight(input.withDayOfMonth(1)));

Update: 2013-08-16 by JodaStephen: Version 2.3 of Joda-Time deprecates DateMidnight as it was a very bad idea of a class.

So use:

DateTime startOfMonth = input.withDayOfMonth(1).withTimeAtStartOfDay();

Answer 3

You can use roundFloorCopy() to mimic DateUtils.truncate

Date truncateMonth = DateUtils.truncate(input, Calendar.MONTH);
-> DateTime truncateMonth = input.dayOfMonth().roundFloorCopy();

Date truncateMinute = DateUtils.truncate(input, Calendar.MINUTE);
-> DateTime truncateMinute = input.minuteOfDay().roundFloorCopy();

Date truncateHourOfDay = DateUtils.truncate(input, Calendar.HOUR_OF_DAY);
-> DateTime truncateHourOfDay = input.hourOfDay().roundFloorCopy()

Answer 4

Joda Time also supports the withFields method in the DateTime type. This can also be used to create a short syntax:

new DateTime().withDayOfMonth(1).withFields(new LocalTime(0, 0));

In production code the argument to withFields should be factored out to a constant.