On 01 Feb 2013, at 10:59, Frank Shearar <[email protected]> wrote:
> On 1 February 2013 09:39, Camillo Bruni <[email protected]> wrote: >> >> On 2013-02-01, at 10:33, Otto Behrens <[email protected]> wrote: >> >>>>> We're not on 2.0 yet and are running on GemStone. Our dates are in a >>>>> local time zone currently, how do we "work" with UTC dates and make >>>>> sure the outside world see the correct date / time? >>>> >>>> Most probably you will get away with it, by only displaying dates/times in >>>> local time zones, but make sure everything internally uses UTC (without >>>> daylight >>>> saving times). >>>> >>>> So you only have to be careful with when inputting data and when >>>> displaying. >>>> Everything that is relative (like your example) will work out of the box. >>> >>> This feels painful. I suppose we'll have to hunt for Dates in the >>> system and migrate them. And then change our subclass of >>> MADateDescription (we use a date picker) to convert to & from the >>> local time zone. And then we have a few timestamps, which is indeed >>> time zone sensitive. >> >> Basically everything will work fine until the point your image crosses >> time-zones. >> Just be careful ;) I burnt my fingers more than once while fixing this mess >> :P >> >> >>> I feel the need for a timezone agnostic Date. But I suppose working >>> with time and duration may complicate things. >> >> yeah, we reached that conclusion at the point we tried to fully grasp the >> scale >> of the problem. So now we have everything internally in UTC, which >> simplifies a lot. > > Sticking with UTC everywhere internally, converting local time -> UTC > on input, and only displaying local time, is the one true way. All > else is madness. Yes, indeed the best way. However, that still does not mean that daylight saving does not exist - when it goes in and out of effect, you will see strange things that might confuse or upset end users counting in their local time zone. BTW, there is ZTimestamp in http://mc.stfx.eu/Neo that is a UTC only, second precision DateAndTime/Timestamp that can represent itself in any TZ. > frank > >>> Thanks for the help. >>> >>>>> How do I write a test for this? >>>> >>>> I presume to properly reproduce the problem you would have to change the >>>> os system-timezone >>>> during a test. Which you could achieve with OSProcess :/ >>> >>> Eeeuw, ok >>> >> >> >
