Re: NSTimestamp bug??
Re: NSTimestamp bug??
- Subject: Re: NSTimestamp bug??
- From: Jonathan Rochkind <email@hidden>
- Date: Mon, 5 Apr 2004 10:56:54 -0500
Figuring out how to properly do date arithmetic in WO is
confusing---there are too many date/time classes in Java already, and
then Apple adds one more, NSTimestamp. And both the Java classes
_and_ the Apple class have a history of bugs---I can never remember
the current status of such bugs in a given Java/WO version. I don't
know for sure why you are seeing the behavior you are seeing, but
given the day you are trying it is right around the US daylight
savings time switch, I suspect daylight savings time might be
implicated. (So if you want to test doing this a different way, you
might want to make sure to use the same input, so it's still right
around the DST switch, to make sure a different way is truly
different).
When I do date arithmetic, I always use Java GregorianCalendar
instead of NSTimestamp's own methods. Which at one point is what the
NSTimestamp documentation reccomended you do, but I'm not sure it
does anymore. But I seem to have had luck with it.
NSTimestamp timestamp; //assume exists
//Create a GregorianCalendar matching the timestamp value
GregorianCalendar myCalendar = new GregorianCalendar();
myCalendar.setTime(myNSTimestamp);
//go back one calendar day
myCalendar.add( GregorianCalendar.DATE, -1 );
//translate back to NSTimestamp
timestamp = new NSTimestamp( myCalendar.getTime() );
--Jonathan
At 11:25 AM -0400 4/5/04, Tom Pelaia wrote:
It appears to me that the timestampByAddingGregorianUnits() method
of NSTimestamp does not properly handle changing by day increments.
The documentation claims that the method preserves "clock time"
across daylight savings changes, but that doesn't appear to be
happening in my application. Instead when I start from 00:00 on
today (Monday) and go back one day I get 23:00 on Saturday. Has
anyone else seen this issue or does it indicate something wrong with
the system clock on our server?
thanks,
-tom
--
Tom Pelaia
SNS Project, 701 Scarboro Road, MS-6473, Oak Ridge, TN 37830
phone: (865)574-6421, fax: (865)574-6617
_______________________________________________
webobjects-dev mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/webobjects-dev
Do not post admin requests to the list. They will be ignored.
_______________________________________________
webobjects-dev mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/webobjects-dev
Do not post admin requests to the list. They will be ignored.