[seam-dev] is there an equivalent of Seam 2 @out in CDI / Seam 3
Pete Muir
pmuir at redhat.com
Tue Apr 5 10:26:31 EDT 2011
On 5 Apr 2011, at 09:47, Antoine Sabot-Durand wrote:
> No it's not a CP : I don't have Weld in my app and I used JBoss 6 out of the box.
> It comes from the conjunction of using
>
> @Inject
> @Any
> private Instance<OAuthServiceHandler> serviceHandlerInstances;
>
> to build list of OAuthServiceHandler beans available. And
>
> @Produces
> @Named
> @RequestScoped
> public OAuthServiceHandler getCurrentServiceHdl()
> {
> return currentServiceHdl;
> }
>
> which creates a null OAuthServiceHandler bean. This Null bean goes into serviceHandlerInstances and as my code is not secured yet against null Bean in the Instance<> iterator I've got a NPE.
> When this NPE is thrown in the @Postconstruct method it creates some kind of stack overflow (trying to recreate the bean again and again after each exception in @Postconstruct) and in the end, the system throws the strange exception : "java.lang.NoClassDefFoundError: org/jboss/weld/exceptions/WeldException"
>
> Sot I've got the following question :
>
> 1) How can I avoid produce null bean (abort bean producing when the value returned by producer method is null) ?
if (blah == null) throw new IllegalStateExeption; ? CDI provides nothing for this case.
> 2) Is there a way to use @Any with a restriction (all qualifier except this one)) ?
No. Just revisit your set logic ;-)
> 3) Shouldn't the exception be a bit more explicit on this issue ;-) ?
Can you file a JIRA issue in WELD for the stack overflow, that shouldn't happen!
Also file one for a poor error message ;-)
>
> Thanks
>
> Antoine SABOT-DURAND
>
>
> Le 4 avr. 2011 à 22:22, Jason Porter a écrit :
>
>> That looks to me like you're having CP issues. Do you have the weld jars in your archive as well as the app server?
>>
>> WRT the @Out question if you want the same kind of functionality you have to create a wrapper component and play the scope game with it that way (Conversation scoped wrapper with a setter for the actual instance).
>>
>> Hope that helps.
>>
>> Sent from my iPhone
>>
>> On Apr 4, 2011, at 15:42, Antoine Sabot-Durand <antoine at sabot-durand.net> wrote:
>>
>>> Hi Dan and Team,
>>>
>>> Sorry to go back to this subject but I don't get the expected result from @produces.
>>> In Seam social Web client example, I tried to outject currentServiceHdl in SocialClient bean like this :
>>>
>>> @Produces
>>> @Named
>>> public OAuthServiceHandler getCurrentServiceHdl()
>>> {
>>> return currentServiceHdl;
>>> }
>>>
>>> and I get the following exception when Social client is initialized (apparently in the @Postconstruct callback) from JSF call (notice that currentServiceHdl is not in the JSF view that triggers the exception only socilaClient) :
>>>
>>>
>>> java.lang.NoClassDefFoundError: org/jboss/weld/exceptions/WeldException
>>> at org.jboss.weld.bean.AbstractClassBean.defaultPostConstruct(AbstractClassBean.java:595)
>>> at org.jboss.weld.bean.ManagedBean$ManagedBeanInjectionTarget.postConstruct(ManagedBean.java:200)
>>> at org.jboss.weld.bean.ManagedBean.create(ManagedBean.java:340)
>>> at org.jboss.weld.context.AbstractContext.get(AbstractContext.java:121)
>>> at org.jboss.weld.bean.proxy.ContextBeanInstance.getInstance(ContextBeanInstance.java:99)
>>> at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:87)
>>> at org.jboss.seam.social.example.webclient.org$jboss$weld$bean-jboss$classloader:id="vfs:$$$Users$antoine$Documents$Eclipse_workspaces$seam-social$$metadata$$plugins$org$jboss$ide$eclipse$as$core$JBoss_6$0_Runtime_Server1295753022377$deploy$seam-social-web-client$war"-ManagedBean-class_org$jboss$seam$social$example$webclient$SocialClient_$$_WeldClientProxy.getServiceHandlers(org$jboss$weld$bean-jboss$classloader:id="vfs:$$$Users$antoine$Documents$Eclipse_workspaces$seam-social$$metadata$$plugins$org$jboss$ide$eclipse$as$core$JBoss_6$0_Runtime_Server1295753022377$deploy$seam-social-web-client$war"-ManagedBean-class_org$jboss$seam$social$example$webclient$SocialClient_$$_WeldClientProxy.java)
>>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>>>
>>>
>>> removing @Produces @Named make the exception disappears.
>>>
>>> Any clue ?
>>>
>>> Antoine SABOT-DURAND
>>>
>>>
>>> Le 16 mars 2011 à 23:09, Antoine Sabot-Durand a écrit :
>>>
>>>> Thanks for the douse I'm going to test this right away.
>>>>
>>>> Antoine Sabot-Durand
>>>>
>>>> Le 16 mars 2011 à 18:29, Dan Allen <dan.j.allen at gmail.com> a écrit :
>>>>
>>>>> You can create a producer that aliases a name to a property, like this:
>>>>>
>>>>> @Produces @Named
>>>>> public Hotel getHotel() { return booking.getHotel(); }
>>>>>
>>>>> #{hotel}
>>>>>
>>>>> You can also use a producer field, like so:
>>>>>
>>>>> @Produces @Named
>>>>> private Hotel hotel;
>>>>>
>>>>> #{hotel}
>>>>>
>>>>> Produces sort of turns outjection on it's head. But if you think about it, it's a better way to go about it because it's more robust to read the state of the model as it is, then try to shift the information around into variables from which to read them, as outjection did.
>>>>>
>>>>> What you can't do is use the same variable name to refer to state on two different models, unless of course your producer method does some conditional logic (saying if this screen, give this result, if this screen, give a different result). But again, that's a good thing because then tooling can actually tell you where the data is coming from.
>>>>>
>>>>> This is a key topic for the migration guide. Feel free to contribute examples of how you might solve an outjection scenario with produces. It's a good exercise anyway.
>>>>>
>>>>> -Dan
>>>>>
>>>>> On Wed, Mar 16, 2011 at 13:03, Ken Finnigan <ken at kenfinnigan.me> wrote:
>>>>> If you want the result of @Produces to be EL accessible just throw a @Named on it.
>>>>>
>>>>> Ken
>>>>>
>>>>> Sent from my iPhone
>>>>>
>>>>> On Mar 16, 2011, at 13:02, Antoine Sabot-Durand <antoine at sabot-durand.net> wrote:
>>>>>
>>>>>> For what I understand, it's not quite the same. I think it's more like @Factory, but I agree it's nearly the same and I could use it was possible to "Named" the "outjected" property in order to use it in EL...
>>>>>>
>>>>>> Antoine
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Le 16 mars 2011 à 17:54, Ken Finnigan a écrit :
>>>>>>
>>>>>>> Antoine,
>>>>>>>
>>>>>>> I'm pretty sure the equivalent for CDI is to use @Produces.
>>>>>>>
>>>>>>> Ken
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Mar 16, 2011 at 12:47 PM, Antoine Sabot-Durand <antoine at sabot-durand.net> wrote:
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I try to shorten my Expression language code and don't want to create delegate methods in my controller to access propertir of a business component.
>>>>>>>
>>>>>>> I didn't found something like @Out. Does it exists ?
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Antoine
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> seam-dev mailing list
>>>>>>> seam-dev at lists.jboss.org
>>>>>>> https://lists.jboss.org/mailman/listinfo/seam-dev
>>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Dan Allen
>>>>> Principal Software Engineer, Red Hat | Author of Seam in Action
>>>>> Registered Linux User #231597
>>>>>
>>>>> http://www.google.com/profiles/dan.j.allen#about
>>>>> http://mojavelinux.com
>>>>> http://mojavelinux.com/seaminaction
>>>>>
>>>
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>
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