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What is the best way to represent week of year with Joda-Time library? I'm looking something as elegant as YearMonth is for representing month of year.

Basil Bourque
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michal.kreuzman
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2 Answers2

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After some searching I found solution using Partial class for this problem.

Partial yearWeek = new Partial(
                   new DateTimeFieldType[] {DateTimeFieldType.weekyear(), 
                                            DateTimeFieldType.weekOfWeekyear()}, 
                                            new int[] {year, week});
michal.kreuzman
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    If you are using this extensively you may want to consider implementing the `YearWeek` partial as explicit final subclass of `BasePartial`, using joda's implementation of `YearMonth` as blueprint. And while on it, you could even contribute it back. :-) – benjamin Nov 27 '12 at 17:48
  • @benjamin I exactly did this, because I need it at more places in application. So I can contribute it. But is it appropriate place it here? – michal.kreuzman Nov 28 '12 at 14:02
  • I have neither contributed to JodaTime yet, but I don't think SOF is the right place to put it. The easiest way is probably to file a feature request on [jodatime's issue tracker](http://sourceforge.net/p/joda-time/bugs/) and attach your class and test sources. Then the jodatime team may descide to accept it or not to, but anyone looking for that feature may find your code and use it. – benjamin Nov 28 '12 at 15:08
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    @michal.kreuzman hi michal, i need a similar thing, did you share your code anywhere? – Marsellus Wallace Jan 09 '14 at 17:26
2

tl;dr

org.threeten.extra.YearWeek.of( 2018 , 28 )

java.time

The Joda-Time project is now in maintenance mode, with the team advising migration to the java.time classes.

org.threeten.extra.YearWeek

The java.time classes are extended by the ThreeTen-Extra project. This project includes the YearWeek class, just what you need.

Beware that "week" can have many definitions. The one used here is defined by the ISO 8601 standard, where the week # 1 contains the first Thursday of the calendar year, and Monday starts each week. So a year has either 52 or 53 weeks. A week-based year may contain a few days from the previous/succeeding calendar year around the end of December and beginning of January.

Pass the number of the week-based year, and the week number.

YearWeek yw = YearWeek.of( 2018 , 7 ) ;

Get a date within that week by specifying a day-of-week via the DayOfWeek enum.

LocalDate wednesdayOf2018W07 = yw.atDay( DayOfWeek.THURSDAY ) ;

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Basil Bourque
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