I think we should be Calendar agnostic in code and like most i18n capable systems, not expect the timestamp in the database to be Calendar-specific Postgres for instance uses Julian calendar internally. But still supports many different systems, much more than standard SQL asks for. Java similar uses long values, instead of Calendar-specific representations.
My point is, Java, Postgres (and MySQL) are well designed to work by being calendar-agnostic. Also, Joda-time<http://joda-time.sourceforge.net/apidocs/org/joda/time/chrono/package-summary.html>provides nice Chronology classes for different calendars, which we can use for localized storing, retrieving or converting For the JavaME app in one of the releases, we did have a custom calendar component. Having it display BS, Ethiopian or anything else, should be fairly easy. But yes, very few low-end Java phones are locale specific. --- Regards, Saptarshi PURKAYASTHA My Tech Blog: http://sunnytalkstech.blogspot.com You Live by CHOICE, Not by CHANCE On 13 April 2013 10:36, Jason Pickering <jason.p.picker...@gmail.com> wrote: > Hi Saptarshi, > Yes, I cannot speculate really why DHIS2 only supports the Gregorian > calendar, but this issue I think has been discussed a few times on the list > before (perhaps for other countries). > > I feel the best approach would be to store all of the data with Gregorian > dates, but what is shown through the web UI would be the calendar system of > the particular instance. I am not even sure if databases like Postgres and > MySQL (much less the operating system itself) would support non Gregorian > calendar systems. > > As for data exchange, I see no immediate need for this, but if data is > stored in Gregorian format ( I suppose the de facto international > standard), then perhaps data exchange would be somewhat easier, but this is > just speculation of course. > > Thanks for the link to the BS date picker. Does not seem to difficult to > solve at least this problem.The bigger issue as I see it would be data > entry through mobiles. At least the J2ME app uses the system calendar, and > do not think that non-Gregorian systems are even supported on any phone? > > Best regards, > Jason > > > > > > On Fri, Apr 12, 2013 at 5:16 PM, Saptarshi Purkayastha > <sun...@gmail.com>wrote: > >> Hi Jason, >> >> When you say the system currently only support Gregorian calendar, I >> wonder if that's a fact of JavaScript widgets >> But while I was writing this email, a quick search in the code base shows >> that we've instantiated Gregorian calendar at many places instead of using >> the more localized Calendar.getInstance(). The first task would be move to >> using this >> >> Secondly, is conversion between Gregorian dates and some other calendar >> really required. If data is exchanged between different systems with >> different calendars, this is important. But if we are storing a timestamp >> in database, it should be fine to store it in the locale calendar. So I am >> not too keen, unless really required to use the maps that allow co-relating >> dates between calendar systems. >> >> Thirdly, there are quite a few (and fairly easy to write new JavaScript >> calendars) to suite different locales. The care that we need to take is >> being able to retrieve the correct calendar based on the set locale. A >> simple BS calendar JS - >> http://sajanmaharjan.com.np/my-works/nepali-datepicker-ui/ >> >> --- >> Regards, >> Saptarshi PURKAYASTHA >> >> My Tech Blog: http://sunnytalkstech.blogspot.com >> You Live by CHOICE, Not by CHANCE >> >> >> On 12 April 2013 12:56, Jason Pickering <jason.p.picker...@gmail.com>wrote: >> >>> Hi Devs, >>> I have a question regarding non-Gregorian (Western) calendar systems. >>> This issue has come up in a couple of different places which I know of, >>> namely Ethiopia (Ethiopian calendar) and Afghanistan (Solar Hijri >>> calendar). Currently, the system only supports a Gregorian calendar system, >>> but I am trying to think of ways how we can support different >>> ones, specifically the Bikram Sambat (BS) calendar system used in Nepal. >>> >>> >>> There appears to be no easy way to convert between a Gregorian >>> calendar. I dug out some code here >>> <https://github.com/bahadurbaniya/Date-Converter-Bikram-Sambat-to-English-Date> >>> which >>> will convert between Gregorian dates and BS dates (but not the other way >>> around). The approach is to use a look-up table, because of the fact that >>> it seems to be difficult (if not impossible) to calculate the >>> conversion algorithmically. >>> >>> This leads me to my question. Would it be possible that we consider >>> adding a "Calendar system" to the application. The default would be >>> "Gregorian", which is currently the case. The Second alternative might be >>> "Bikram Sambat". This would require someone to prepopulate the system with >>> periods (BS months, quarters and years) which would be calculated through >>> some other means (common Lisp code >>> here<http://emr.cs.uiuc.edu/~reingold/calendar.l> which >>> may be able to do this). These would be in Gregorian periods, but instead >>> of the system calculating future periods, they would have to be >>> pre-calculated and entered/imported into the system somehow. >>> >>> The second part of this (which I think may be more difficult) is the use >>> of the JavaScript Gregorian calendar throughout the system. For data entry >>> of aggregate data, it would not to be too problematic. But for the tracker >>> module (and other places in the system), a Gregorian Javascript widget is >>> used, and it would seem to be potentially difficult to replace this. >>> >>> Could the developers comment on feasibility and possible level of effort? >>> >>> Best regards, >>> Jason >>> >>> >>> _______________________________________________ >>> Mailing list: https://launchpad.net/~dhis2-devs >>> Post to : dhis2-devs@lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~dhis2-devs >>> More help : https://help.launchpad.net/ListHelp >>> >>> >> >
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