Two servlet filters - one to do 95% of the work, the second to cleanup any thread locals.
Don On Thu, Apr 25, 2013 at 1:06 AM, Lukasz Lenart <lukaszlen...@apache.org>wrote: > Thanks MrDon :-) > > What you mean by "two filters"? > > > Regards > -- > Łukasz > + 48 606 323 122 http://www.lenart.org.pl/ > > 2013/4/24 Don Brown <donald.br...@gmail.com>: > > This all goes way back to the days of WebWork and how much they loved > > statics. WebWork basically used static singletons for everything, > causing > > a) a really complicated startup order and b) the ability to only run one > > instance of the framework. In those days (and perhaps still?) there > wasn't > > just one filter but at least two to allow proper thread-local cleanup, > > because what wasn't accessed statically was accessed statically using > thread > > locals as the means (ActionContext.getContext() for example). > > > > Therefore, with two filters that contain state that needs to be accessed > > statically, we were limited to threadlocals to track that state. When I > was > > working on it, I got it to the point that most statics were gone and we > had > > a decent injection system to avoid all the static accessors, but they > were > > still there in case you needed them. I don't know what the code is like > > now, but it sounds like perhaps it still hasn't completely gotten away > from > > statics and threadlocals. > > > > As a side note, back then (2008?) we did some profiling and found that > > actually all the thread locals were eating up a bunch of time in the > > request, so it is more than just a general "icky" sense that should drive > > their removal. > > > > Again, my knowledge is pretty dated, but that's where things came from. > > > > Don > > > > > > On Tue, Apr 23, 2013 at 7:40 PM, ppm10103 <ppm10...@163.com> wrote: > >> > >> > >> At 2013-04-24 03:44:22,"Lukasz Lenart" <lukaszlen...@apache.org> wrote: > >> > >> >2013/4/23 ppm10103 <ppm10...@163.com>: > >> >> The Dispatcher will have only one instance, > >> >> it bind to ThreadLocal is for what? > >> > > >> >For thread safety, then you can access Dispatcher from a thread > >> >without synchronisation. That's my opinion :-) > >> > > >> > > >> >Regards > >> >-- > >> >Łukasz > >> >+ 48 606 323 122 http://www.lenart.org.pl/ > >> > > >> >--------------------------------------------------------------------- > >> >To unsubscribe, e-mail: dev-unsubscr...@struts.apache.org > >> >For additional commands, e-mail: dev-h...@struts.apache.org > >> > > >> > >> Thanks for your help,but I look into the sourcecode ,the Dispatcher will > >> only be one instance, > >> so even put it in the ThreadLocal,every thead alse access the same > >> Dispatcher instance, > >> so I think it's not for thread safe,so I still want to konw it's for > what? > > > > >
