jsr372-experts@javaserverfaces-spec-public.java.net

[jsr372-experts] Re: [527-InjectFacesContext] Support and review

From: manfred riem <manfred.riem_at_oracle.com>
Date: Mon, 06 Oct 2014 10:10:38 -0500

Hi Arjan,

Can you verify if the proxying works properly by writing some tests that
exercise the injection of the FacesContext using @Inject into the
managed beans using following scope types (@RequestScoped,
@SessionScoped, @FlowScoped, @ViewScoped, @ApplicationScoped)?

If we can verify that all are working as expected I think from a
developer perspective this is enough. For any of the other corner use
cases I think we should push back for now, unless someone wants to
spearhead the work on that. Any takers?

Thanks!
Manfred

On 9/25/14, 4:56 PM, arjan tijms wrote:
> Hi,
>
> On Thu, Sep 25, 2014 at 6:58 PM, Neil Griffin
> <neil.griffin_at_portletfaces.org <mailto:neil.griffin_at_portletfaces.org>>
> wrote:
>
> The JSF Portlet Bridge will make beans annotated with
> javax.faces.bean.RequestScoped survive from the ACTION_PHASE to
> the RENDER_PHASE.
>
> But CDI does not do that. If a JSF portlet developer annotates a
> bean with javax.enterprise.context.RequestScoped, then CDI creates
> a new bean in both the ACTION_PHASE and RENDER_PHASE.
>
>
> I have to admit I know almost nothing about Portlets, but if I
> understand correctly this is thus a general problem
> with javax.enterprise.context.RequestScoped and Portlets, and not
> specifically with injecting a request scoped FacesContext, right?
>
> But in this case would it really matter? If a single CDI request scope
> does not survive beyond the Portlet action phase and into the render
> phase, then there would simply be one additional call to
> FacesContext#getCurrentInstance if the proxy is referenced again in
> the render phase, right? This then grabs the current FacesContext
> according to the existing JSF rules and all should be right again. Or
> am I missing something obvious?
>
> If there is a successor to JSR 329, then one of the requirements
> for that new JSR *might* be to re-define the behavior
> of javax.enterprise.context.RequestScoped.
>
>
> Just wondering, but isn't JSR 329 specifically designed for
> interoperability with JSF 1.2 only?
>
> Kind regards,
> Arjan
>
>
> On Sep 25, 2014, at 12:36 PM, Leonardo Uribe
> <leonardo.uribe_at_irian.at <mailto:leonardo.uribe_at_irian.at>> wrote:
>
>> Hi
>>
>> I know that the trick using @RequestScoped works, but
>> Is there a 1-1 relationship between FacesContext lifecycle
>> and the request lifecycle? That works fine on servlets but
>> it doesn't on portlets (action request / render request).
>>
>> It is possible to imagine other scenarios where this
>> assumption just fail. In my opinion, we should take the
>> long route, create a CDI scope and use that scope to
>> store the producer, so it get the right instance. After all
>> JSF should be in control of FacesContext lifecycle.
>>
>> regards,
>>
>> Leonardo Uribe
>>
>>
>> 2014-09-25 11:02 GMT-05:00 arjan tijms <arjan.tijms_at_gmail.com
>> <mailto:arjan.tijms_at_gmail.com>>:
>>> Hi,
>>>
>>> On Thu, Sep 25, 2014 at 4:32 PM, Edward Burns
>>> <edward.burns_at_oracle.com <mailto:edward.burns_at_oracle.com>> wrote:
>>>> Arjan, can you take the action item to investigate this and
>>>> report back
>>>> to the group? Such investigations and reports are the bread
>>>> and butter
>>>> of expert group membership and really add significant value
>>>> because the
>>>> results the produce are so actionable.
>>>
>>> I took a quick look, and the results are rather interesting.
>>>
>>> First of all, the feature is described here:
>>> http://docs.jboss.org/seam/3/servlet/latest/reference/en-US/html/injectablerefs.html#injectablerefs.http_servlet_request
>>>
>>> The producer was created by CDI wizards Dan Allen and Nicklas
>>> Karlsson, and for the HttpServletRequest it looks as follows:
>>>
>>> @Produces
>>> @Typed(HttpServletRequest.class)
>>> @RequestScoped
>>> protected HttpServletRequest getHttpServletRequest() {
>>> return holder.getHttpServletRequest();
>>> }
>>>
>>> See:
>>> http://grepcode.com/file/repository.jboss.org/nexus/content/repositories/releases/org.jboss.seam.servlet/seam-servlet/3.1.0.Beta2/org/jboss/seam/servlet/http/ImplicitHttpServletObjectsProducer.java?av=f
>>>
>>> The holder is an application scoped bean, which has as its main goal
>>> to collect and hold on to among others the HttpServletRequest via a
>>> thread local. Collection happens via a CDI event and the listeners
>>> stores the request object into TLS via a wrapper. Abbreviated it's:
>>>
>>> protected void requestInitialized(@Observes @Initialized final
>>> InternalServletRequestEvent e) {
>>> ServletRequest req = e.getServletRequest();
>>> // code omitted
>>> requestCtx.set(new HttpServletRequestContext(req));
>>> }
>>>
>>> See:
>>> http://grepcode.com/file/repository.jboss.org/nexus/content/repositories/releases/org.jboss.seam.servlet/seam-servlet/3.1.0.Beta2/org/jboss/seam/servlet/event/ImplicitServletObjectsHolder.java#70
>>>
>>> But the wrapper doesn't play a role in injection, since when the
>>> producer asks the holder for the request instance, it's unwrapped
>>> again. Abbreviated it's:
>>>
>>> public HttpServletRequest getHttpServletRequest() {
>>> // code omitted
>>> return
>>> HttpServletRequestContext.class.cast(requestCtx.get()).getRequest();
>>> }
>>>
>>> See:
>>> http://grepcode.com/file/repository.jboss.org/nexus/content/repositories/releases/org.jboss.seam.servlet/seam-servlet/3.1.0.Beta2/org/jboss/seam/servlet/event/ImplicitServletObjectsHolder.java#128
>>>
>>> So there's not a lot of magic going at all. The key seems to be that
>>> the producer itself is @RequestScoped, but the instance it produces
>>> doesn't seem to be a request scoped wrapper bean at all, just the
>>> normal instance. I do wonder a bit why they choose TLS storage
>>> instead
>>> of a request scoped bean, but that's beside the issue here.
>>>
>>> As JSF already stores the FacesContext in TLS, the entire holder
>>> construct isn't needed and seemingly the producer would only need to
>>> be annotated with @RequestScoped.
>>>
>>> Kind regards,
>>> Arjan
>
>