StdDateFormat: performance improvement of '_format(..)' method

[brenuart]

The _format(..) method creates a new GregorianCalendar instance for every invocation. Performance would be better if the calendar is reused across invocations just like what is done with the DateFormats.

Without this optimisation, the performance are roughly the same as the SimpleDateFormat. With the optimisation, the StdDateFormat becomes 300% faster...

[cowtowncoder]

Ok good to know, thank you for measuring it. It sort of makes sense as almost everything to do with date/time handling appears to be.... rather expensive. Need to figure out proper way to achieve that but hopefully is doable.

[brenuart]

Check the PR ;-)

[cowtowncoder]

Ah! Only catching up on updates :)