I was about to suggest this. :) And one advantage of using joda time is that version 1.6 is already included as a dependency of drools.
--- On Tue, 2/23/10, Jason Smith <jsm...@infotrustgroup.com> wrote: > From: Jason Smith <jsm...@infotrustgroup.com> > Subject: Re: [rules-users] AGE problem > To: "Rules Users List" <rules-users@lists.jboss.org> > Date: Tuesday, February 23, 2010, 7:45 AM > Hey, I haven't been following this > thread, but you can use Joda Time to get much better, easier > results. For instance, you can add 1 month to a > DateTime by using a new Period("P1M") [that is, a period of > 1 month] - all done according to ISO8601 standards, so it > works flawlessly, including adjustments for things like > daylight savings time (so you don't have to think about it > much). > > In business, we live and die by precise time > calculations. Think of it as being like a check > writing program that "estimates" a salary, and then pays the > employee that amount. Get your torches and > pitchforks! > > Jason Smith > ________________________________________ > From: rules-users-boun...@lists.jboss.org > [rules-users-boun...@lists.jboss.org] > On Behalf Of Pavel Tavoda [pavel.tav...@gmail.com] > Sent: Tuesday, February 23, 2010 1:30 AM > To: Rules Users List > Subject: Re: [rules-users] AGE problem > > Try to do this in bank application. People come 1 hour > after they date > expired and try to charge them for sooner withdrawal > because you > calculate with 365.25 not 365 days. You will be kicked, > believe me. > > Pavel > > > 2010/2/23 Wolfgang Laun <wolfgang.l...@gmail.com>: > > On Tue, Feb 23, 2010 at 8:07 AM, djb <dbrownel...@hotmail.com> > wrote: > >> > >> I think though that the majority of uses for a > rules engine is in a > >> business > >> context, where they don't use astronomical time. > >> > >> If the doctor's orders are: > >> "You cannot get out of bed for 2 months" > >> > >> This means 59 days if he told you February 1st, > and it means 62 days if he > >> told you July 1st. > >> > > > > This is a particularly bad example, because doctors > can't say that - at > > least not one I'd trust ;-) > > > > I'm arguing that you cannot expect a computer program > to relieve you from > > the burden of defining what you mean by a "duration of > one year" (or month). > > Some legal rules require a person to have a certain > age, and it is (for > > humans) > > more convenient to decide this on a person's birthday > YMD plus an increment > > in the Y number. If your application requires > you to use an increment in > > the year > > component of the YMDhms representation of a point in > time, then you are > > indeed stuck with Calendar and the resulting overhead. > (Memoizing > > the results of YMDhms +/- n years might speed things > up, for the usual > > price.) > > > > But many applications would be satisfied with using a > fixed duration for > > a year in terms of 365 or 365.25 or some such value. > If, for instance, you > > have a library, and you must decide to move a > book into deep storage > > "if it has not been requested for more than a > year" you might calculate > > this (faster) by adding 356*24*60*60 to the clock > value of the last return. > > > > -W > > > >> So at least for me, I am going to have to work out > a plan that involves > >> GregorianCalendar. > >> > >> -- > >> View this message in context: > >> http://n3.nabble.com/AGE-problem-tp215215p354847.html > >> Sent from the Drools - User mailing list archive > at Nabble.com. > >> _______________________________________________ > >> rules-users mailing list > >> rules-users@lists.jboss.org > >> https://lists.jboss.org/mailman/listinfo/rules-users > > > > > > _______________________________________________ > > rules-users mailing list > > rules-users@lists.jboss.org > > https://lists.jboss.org/mailman/listinfo/rules-users > > > > > > _______________________________________________ > rules-users mailing list > rules-users@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ > rules-users mailing list > rules-users@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users