[weld-dev] proper handling of Events for beans in inactive Contexts?

[Nicklas Karlsson]

You could use a similar construct like Seam 2 had, the
ContextualHttpServletRequest which essentially enabled the contexts and then
you did your work i an overloaded method but the problem is portability
between CDI implementations for context activation. Or if you could just
move conversation management to a servlet listener. I mailed the EG on both
issues so let's see what comes back from that direction.

On Fri, Apr 9, 2010 at 3:31 PM, Sven Linstaedt <
sven.linstaedt at googlemail.com> wrote:

> As far as I remember, conversation contexts are not available in servlet
> filters (at least in seam version 2.x). Because conversation definition is
> currently tied to JSF lifecycle, the best approach from my experience is
> avoid servlet filter (and others) and only use JSF extension points like
> phase listeners.
>
> br, Sven
>
>
> 2010/4/9 Mark Struberg <struberg at yahoo.de>
>
> Sorry, I don't really get it.
>>
>> If you have a 'transient conversation' and you like to send an event to
>> BeanX and there is no contextual instance of that BeanX already in your
>> transient conversation context, then a new one will get created and the
>> event will get received by this contextual instance.
>>
>> However, a few nanoseconds later the restoreView phase will restore the
>> ViewRoot and we find a cid=4711 there. So we will now lookup this context
>> with cid=4711 and oops, this already contains a contextual instance of BeanX
>> which DIDN'T get the event!
>>
>> So what is the transient conversation really doing? What is it for?
>>
>> Sometimes a context may return isActive() == false and this has a very
>> good reason! Doing any trickery in such cases will imo cause more problems
>> than they solve.
>>
>> LieGrue,
>> strub
>>
>> --- Pete Muir <pmuir at redhat.com> schrieb am Fr, 9.4.2010:
>>
>> > Von: Pete Muir <pmuir at redhat.com>
>> > Betreff: Re: [weld-dev] proper handling of Events for beans in inactive
>> Contexts?
>> > An: "Mark Struberg" <struberg at yahoo.de>
>> > CC: weld-dev at lists.jboss.org
>> > Datum: Freitag, 9. April, 2010 11:37 Uhr
>> > Tricky situation, and something we
>> > "fixed" in Seam by having a transient conversation always
>> > active. I have a feeling that is what CDI should do to.
>> >
>> > On 25 Mar 2010, at 16:49, Mark Struberg wrote:
>> >
>> > > Hi!
>> > >
>> > > I have the following scenario:
>> > >
>> > > *) A ServletFilter fires a UserLoggedInEvent
>> > > *) A @ConversationScoped MyBean @Observes
>> > UserLoggedInEvent with Reception.ALWAYS
>> > >
>> > > The problem here is that the Conversation is not yet
>> > 'opened' at the time the ServletFilter fires that event.
>> > Thus ConversationContext.isActive() == false and I cannot
>> > create this bean.
>> > >
>> > > A similar situation appears if you try to send an
>> > event to a @ViewScoped bean from a JSF phase where the
>> > ViewMap doesn't yet exist.
>> > >
>> > > So since there is no way to create a contextual
>> > instance, the obvious solution is to not send the
>> > notification to this very bean.
>> > >
>> > > I didn't find this covered in the spec and I don't yet
>> > see much we can do in this case. This may cause some not so
>> > obvious behaviour and user may wonder why they don't get the
>> > event.
>> > >
>> > > So, should we log some info in this case or silently
>> > swallow it?
>> > >
>> > >
>> > > txs and LieGrue,
>> > > strub
>> > >
>> > >
>> > > __________________________________________________
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>> >
>>
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-- 
---
Nik
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