[Mulgara-dev] XSD Date/Time Corruption reproducible

[Eric Brown]

Hi Paul,

On Jan 25, 2007, at 12:27 PM, Paul Gearon wrote:

> I was about to comment that a one hour difference was too big a  
> coincidence to ignore the possibility of a timezone (or DST)  
> issue.  This is despite the fact that other observed differences  
> have been significantly different.
>
> I was also going to comment that the relevant code is in:
> src/jar/store-stringpool/java/org/mulgara/store/stringpool/xa/ 
> SPDateTimeImpl.java
>
> But then I thought it was just too lazy of me to not look at the  
> code myself before posting.
>
> The problem would seem to be in encoding/decoding, so I tried  
> pulling the relevant java files out, and into a test area where I  
> could look at them in peace.  I then wrote a test class, and found  
> the following:
>
> String datestring = "1981-04-26T02:56:00";
> System.out.println("Normal form:  " + datestring);
> SPDateTimeImpl dti = SPDateTimeImpl.newInstance(datestring);
> System.out.println("Lexical form: " + dti.getLexicalForm());
>
> Gives the following output:
> Normal form:  1981-04-26T02:56:00
> Lexical form: 1981-04-26T03:56:00
>
> Gak.
>
> When I change the original string to "1981-04-26T03:56:00" then the  
> output becomes:
> Normal form:  1981-04-26T03:56:00
> Lexical form: 1981-04-26T03:56:00
>
> Double Gak.
>
> After looking at the internal data structures, I narrowed it down  
> the parser in newInstance.  Unfortunately, the bug here is in a  
> third party date parser from Mouse Pushers (which I'd never heard  
> of before today).  If you try the following code:
>
> Date date = DateParser.parse(
>         "1981-04-26T02:56:00.000",
>         "yyyy-MM-dd'T'HH:mm:ss.SSS",
>         Locale.getDefault());
> System.println(date.toString());
>
> Then the output is:
> Sun Apr 26 03:56:00 CDT 1981
>
> Note that the hour has changed from 2 to 3.  It doesn't get changed  
> when the time starts at 3:56.  I suspect you will find that all of  
> your problem dates will show up incorrectly from this parser.
>
> So it's not Mulgara's fault!!!  :-)
>
> Unfortunately, there is no more recent version of this parsing  
> library, so we either have to debug the source code ourselves  
> ( http://www.mousepushers.com/java.html) or else we find/write  
> another date parser.  Anyway, I'm *supposed* to be working, so I  
> have to leave it here until tonight.

You might want to look at joda. It seems very complete and under  
active development. Don't know about performance.

http://joda-time.sourceforge.net/

Cheers,
Eric

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