[wildfly-dev] JSF and JSP activation

[arjan tijms]

Hi,

I'm already on this list indeed ;)

Indeed, the FacesInitizalizer only does these two things unconditionally:

boolean appHasSomeJsfContent = appMayHaveSomeJsfContent(classes,
servletContext);
boolean appHasFacesServlet =
getExistingFacesServletRegistration(servletContext) != null;

As can be seen from the code, it looks at the classes provided by the
Servlet container, for a faces-config.xml in WEB-INF, and for the CDI bean
annotated with @FacesConfig (which is a single CDI lookup).

Note though that WildFly is using a somewhat older Mojarra release, so the
code is a bit different in WildFly, although not that much.

So if the application is not actually using JSF, that's all it does. And
there should not be any additional overhead. If the application does use
JSF indeed, there's overhead and that's indeed too much overhead. I've been
trying on reducing this, for instance by using a pre-parsed internal
faces-config file.

See specifically this commit:
https://github.com/javaserverfaces/mojarra/commit/0129ffe2aadb4e87f46d094159cee0910f73003a

@Stuart, I wonder what the overhead is that you see when the application is
not using JSF, and which test application you are actually using. Could it
be that you somehow have a FacesServlet or faces-config.xml etc anyway?

Kind regards,
Arjan






On Tue, Apr 3, 2018 at 7:50 AM, Guillermo González de Agüero <
z06.guillermo at gmail.com> wrote:

> This would be great to have!
>
> As for JSF activation, note that faces-config.xml nor Faces Servlet are
> required anymore. There's also a new @FacesConfig CDI qualifier on JSF 2.3
> which substitutes faces-config.
>
> Looking at FacesConfigInitializer class[1] might provide some more
> insight. I've always been puzzled with the "Initializing Mojarra" log when
> deploying a JAX-RS only app. The mentioned class supposedly should prevent
> JSF from unnecessary initializing. Perhaps some work could be done there
> which helps also other runtimes?
>
> Btw, I think he is already subscribed to the list, but I'm cc'ing Arjan
> Tijms since he's the expert on this stuff.
>
>
> Regards,
>
> Guillermo González de Agüero
>
> [1] https://github.com/javaserverfaces/mojarra/blob/
> 4ea1679838f5a6bf6899c282964ff241c020e2f9/impl/src/main/java/
> com/sun/faces/config/FacesInitializer.java
>
> El mar., 3 abr. 2018 a las 3:16, Stuart Douglas (<
> stuart.w.douglas at gmail.com>) escribió:
>
>> Hi Everyone,
>>
>> At the moment JSP and JSF are being activated for all web deployments,
>> which is relatively expensive as this involves quite a bit of class loading
>> and TLD parsing.
>>
>> To give an idea about how much time this is actually taking I did a test
>> with a large number of small servlet only deployments both with and without
>> JSF, and JSF was accounting for 20% of total deployment time even though it
>> was not actually used by any of the deployments.
>>
>> It also had a significant effect on memory usage, as the parsed TLD's are
>> retained, and are quite large.
>>
>> The root of this issue is that the spec does not define clear activation
>> criteria for these technologies. I am proposing that we formalise some
>> activation criteria, so that we can avoid activating them if they are not
>> required.
>>
>> JSP:
>>
>> For JSP I think we can use the following criteria (if either one is
>> satisfied JSP is activated):
>>
>> - The presence of a JSP file mapping in web.xml
>> - The presence of JSP files inside the deployment
>> - The presence of JSF
>>
>> One thing that does concern me is that searching for JSP files in this
>> way may be expensive in large deployments with lots of web resources. An
>> alternate approach may be to try and make JSP lazy, so class loading and
>> TLD passing does not happen until a request for a JSP file arrives.
>>
>>
>> JSF:
>>
>> This is much less clear. I think we can use the presence of one of the
>> following:
>>
>> - faces-config.xml
>> - The faces servlet in web.xml
>> - Something else?
>>
>> I am not really sure what effect this will have on backwards
>> compatibility though. If this is a compatibility problem we could add an
>> attribute to the JSF subsystem to restore the old mode.
>>
>>
>> Does this sound reasonable?
>>
>> Stuart
>>
>>
>>
>>
>> _______________________________________________
>> wildfly-dev mailing list
>> wildfly-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/wildfly-dev
>
>
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