Von: Pete Muir <pmuir(a)redhat.com&gt; Betreff: Re: [weld-dev] proper handling of Events for beans in inactive Contexts? An: "Mark Struberg" <struberg(a)yahoo.de&gt; CC: weld-dev(a)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 > > > __________________________________________________ > Do You Yahoo!? > Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. > http://mail.yahoo.com > > _______________________________________________ > weld-dev mailing list > weld-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/weld-dev

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(a)yahoo.de&gt; 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(a)redhat.com&gt; schrieb am Fr, 9.4.2010: > > > Von: Pete Muir <pmuir(a)redhat.com&gt; > > Betreff: Re: [weld-dev] proper handling of Events for beans in inactive > Contexts? > > An: "Mark Struberg" <struberg(a)yahoo.de&gt; > > CC: weld-dev(a)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 > > > > > > > > > __________________________________________________ > > > Do You Yahoo!? > > > Sie sind Spam leid? Yahoo! Mail verfügt über einen > > herausragenden Schutz gegen Massenmails. > > > http://mail.yahoo.com > > > > > > _______________________________________________ > > > weld-dev mailing list > > > weld-dev(a)lists.jboss.org > > > https://lists.jboss.org/mailman/listinfo/weld-dev > > > > > > __________________________________________________ > Do You Yahoo!? > Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz > gegen Massenmails. > http://mail.yahoo.com > > _______________________________________________ > weld-dev mailing list > weld-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/weld-dev > _______________________________________________ weld-dev mailing list weld-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/weld-dev

This was just one example! My point was that the spec should clearly define what will happen if a context is not active at the time the event get's sent. Exchange @ConversationScoped with @ViewScoepd in my example. This context is only available after the ViewMap got restored. And there is no way to move the ViewMap restoration into a ServletListener. So there will be situations where we have to deal with this situation somehow. LieGrue, strub --- Nicklas Karlsson <nickarls(a)gmail.com&gt; schrieb am Fr, 9.4.2010: Von: Nicklas Karlsson <nickarls(a)gmail.com&gt; Betreff: Re: [weld-dev] proper handling of Events for beans in inactive Contexts? An: "Sven Linstaedt" <sven.linstaedt(a)googlemail.com&gt; CC: "Mark Struberg" <struberg(a)yahoo.de&gt;, "Pete Muir" <pmuir(a)redhat.com&gt;, weld-dev(a)lists.jboss.org Datum: Freitag, 9. April, 2010 14:52 Uhr 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(a)googlemail.com&gt; 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(a)yahoo.de&gt; 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(a)redhat.com&gt; schrieb am Fr, 9.4.2010: > Von: Pete Muir <pmuir(a)redhat.com&gt; > Betreff: Re: [weld-dev] proper handling of Events for beans in inactive Contexts? > An: "Mark Struberg" <struberg(a)yahoo.de&gt; > CC: weld-dev(a)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 > > > > > > __________________________________________________ > > Do You Yahoo!? > > Sie sind Spam leid? Yahoo! Mail verfügt über einen > herausragenden Schutz gegen Massenmails. > > http://mail.yahoo.com > > > > _______________________________________________ > > weld-dev mailing list > > weld-dev(a)lists.jboss.org > > https://lists.jboss.org/mailman/listinfo/weld-dev > > __________________________________________________ Do You Yahoo!? Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. http://mail.yahoo.com _______________________________________________ weld-dev mailing list weld-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/weld-dev _______________________________________________ weld-dev mailing list weld-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/weld-dev -- --- Nik __________________________________________________ Do You Yahoo!? Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. http://mail.yahoo.com

Von: Pete Muir <pmuir(a)redhat.com&gt; Betreff: Re: [weld-dev] proper handling of Events for beans in inactive Contexts? An: "Pete Muir" <pmuir(a)redhat.com&gt; CC: "Mark Struberg" <struberg(a)yahoo.de&gt;, weld-dev(a)lists.jboss.org Datum: Freitag, 9. April, 2010 16:43 Uhr Mark has pointed out that for Reception.ALWAYS he agrees that an exception should be thrown, but that for Reception.IF_EXISTS he thinks that an exception should not be thrown. I agree this is certainly a nicer way for the programmer to work (and is semantically correct IMO). I think the spec should be clarified to state that this the case, in the meantime we will implement this in Weld. https://jira.jboss.org/jira/browse/WELD-480 On 9 Apr 2010, at 15:04, Pete Muir wrote: > I believe it's fairly clear that a ContextNotActiveException will be thrown. Hence why we are all addressing ways to get around your problem rather than what the spec requirements are ;-) > > Why do you think it isn't clear? > > On 9 Apr 2010, at 14:02, Mark Struberg wrote: > >> This was just one example! >> >> My point was that the spec should clearly define what will happen if a context is not active at the time the event get's sent. >> >> Exchange @ConversationScoped with @ViewScoepd in my example. This context is only available after the ViewMap got restored. And there is no way to move the ViewMap restoration into a ServletListener. >> >> So there will be situations where we have to deal with this situation somehow. >> >> LieGrue, >> strub >> >> --- Nicklas Karlsson <nickarls(a)gmail.com&gt; schrieb am Fr, 9.4.2010: >> >> Von: Nicklas Karlsson <nickarls(a)gmail.com&gt; >> Betreff: Re: [weld-dev] proper handling of Events for beans in inactive Contexts? >> An: "Sven Linstaedt" <sven.linstaedt(a)googlemail.com&gt; >> CC: "Mark Struberg" <struberg(a)yahoo.de&gt;, "Pete Muir" <pmuir(a)redhat.com&gt;, weld-dev(a)lists.jboss.org >> Datum: Freitag, 9. April, 2010 14:52 Uhr >> >> 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(a)googlemail.com&gt; 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(a)yahoo.de&gt; >> >> 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(a)redhat.com&gt; schrieb am Fr, 9.4.2010: >> >>> Von: Pete Muir <pmuir(a)redhat.com&gt; >>> Betreff: Re: [weld-dev] proper handling of Events for beans in inactive Contexts? >>> An: "Mark Struberg" <struberg(a)yahoo.de&gt; >>> CC: weld-dev(a)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 >>>> >>>> >>>> __________________________________________________ >>>> Do You Yahoo!? >>>> Sie sind Spam leid? Yahoo! Mail verfügt über einen >>> herausragenden Schutz gegen Massenmails. >>>> http://mail.yahoo.com >>>> >>>> _______________________________________________ >>>> weld-dev mailing list >>>> weld-dev(a)lists.jboss.org >>>> https://lists.jboss.org/mailman/listinfo/weld-dev >>> >>> >> >> __________________________________________________ >> Do You Yahoo!? >> Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. >> http://mail.yahoo.com >> >> _______________________________________________ >> weld-dev mailing list >> weld-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/weld-dev >> >> >> _______________________________________________ >> weld-dev mailing list >> weld-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/weld-dev >> >> >> >> -- >> --- >> Nik >> >> __________________________________________________ >> Do You Yahoo!? >> Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. >> http://mail.yahoo.com > > > _______________________________________________ > weld-dev mailing list > weld-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/weld-dev