Finishing timezone support for Antville was pretty painless - all I had to do was make sure that date parsing and formatting are always done through parseTimestamp() and formatTimestamp() functions, which take in account the local weblog's localisation and timezone, if a weblog object is present in the request path. All dates are still stored in local server time. Both parseTimestamp() and formatTimestamp() are in global now, although weblog.formatTimestamp() is still there for backward compatibility - I didn't want to go through all the code - but all it does now is to forward the call to the global formatTimestamp() function.

The fact that the weblog object for date localization is always taken from the request path (i.e. path.weblog) causes one significant change: If an object from one weblog is used from within a page of another weblog or the application root area, the language and timezone from the embedding environment will be used for rendering dates, not those of the object's home weblog. In my opinion this makes sense because with timezone support, dates would not only be rendered in a strange language, but could also be a few hours off, i.e. you'd see dates in different timezones mixed together in one page. However, if this functionality is needed, it would be possible to format dates according to their home weblog by passing either the weblog or the locale and timezone to the formatTimestamp() function.

Finally, I implemented caching of java.text.SimpleDateFormat objects. These things are pretty expensive to create since the format has to be parsed each time. On the other hand, reuse is difficult because the class is not thread safe and would produce broken output if used by multiple threads at the same time. My solution is to cache them in the res.data object, using the format string such as "short", "yyyyMMdd" etc as key. front page rendering is now about 10% faster, and the gain could be even larger for pages with many dates.

Right now, the changes are still in the hns_timezone branch. I'll test some more and eventually merge changes to the main branch if that's ok.