On 27 January 2012 13:58, Clive D.W. Feather <[email protected]> wrote: > Stephen Colebourne said: >>> Oh? When is a month from Monday coming? What day is 4 months after the last >>> day of next month? What about the antepenultimate day of next month? >>> Explain your working in each case. >> Each of those three examples requires the day-of-week, > > The first does, but only because I didn't phrase it as "When is a month > from 30th January?", which is what I meant. > >> The point of storing data in this form is that most queries of a date >> are for year, month and day-of-month. Similarly, most sets/adds, like >> 2012-01-31 + 1month require the year, month and day-of-month. In the >> format above, those calculations are easy. > > Okay, all of those three (as amended in the first case) are of that form: > > 2012-01-30 + 1 month > 2012-02-29 + 4 months > 2012-02-27 + 4 months > > and let me add: > > 2011-02-28 + 1 year
OK, I mean easy in computation, you mean easy as in well-defined result. JSR-310 currently has a resolver plugin that you can specify to control the result. http://threeten.sourceforge.net/apidocs-2011-01-07/javax/time/calendar/DateResolvers.html The default is previous-valid: 2012-01-30 + 1 month = 2012-02-29 2012-02-29 + 4 months = 2012-06-29 2012-02-27 + 4 months = 2012-06-27 2012-02-29 + 1 year = 2013-02-28 2011-02-28 + 1 year = 2012-02-28 Stephen _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
