[weld-dev] Question about conversations scope initilization obeserver

Tue Jan 28 10:54:47 EST 2020

Thank you Matej, 

I will report this info back to my client, hopefully they will be 
satisfied with this answer. 

Best regards
Benjamin

From:   Matej Novotny <manovotn at redhat.com>
To:     Benjamin Confino <BENJAMIC at uk.ibm.com>
Cc:     Takayuki T Ishii <EBB0F3L at jp.ibm.com>, weld-dev at lists.jboss.org
Date:   28/01/2020 15:03
Subject:        [EXTERNAL] Re: [weld-dev] Question about conversations 
scope initilization     obeserver

Hello,

I think I know what is the "problem" here.
Weld uses lazy conversation init - that means we don't activate context 
until you try and access a conversation scoped bean.

Now, in your example, the ConversationBean tries to begin() a 
conversation, then calls the bean (which initializes the context and 
notifies the observer).
However, in the situation where you try and pass in a non-existing 
conversation, the invocation to conversation.begin()[1] will blow up with 
NonExistingConversationException and
you will jump right into the catch block[2] where you begin a conversation 
with given ID, but you no longer invoke the bean, hence the context won't 
get activated.
Try adding the `bean.getMsg()` call to the catch block and see if that 
helps.

Note that CDI spec sets no requirements on how/when to activate the 
conversation context, so the lazy behaviour is compliant with spec (and 
this is also why you saw no such test in TCKs).

Regards
Matej

_________________________________________________________________________________
[1] 
https://urldefense.proofpoint.com/v2/url?u=https-3A__gist.github.com_manovotn_b9e9fde25ab77b5e481d5b34edf02b0c-23file-2Dconversationbean-2Djava-2DL4&d=DwICaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=hl8XiFr1UrTSgyXVc4KO_i51sM3Gyhlu1KZ4TkyseEQ&m=uvdQf1sxR6VmxxDyV0JaOkEISRIJR3-N8dd2BXxazMQ&s=2TlH_k5wLmD8CYWrNh6BC2oYQwPs04gBfwJZ7yGgTjo&e= 

[2] 
https://urldefense.proofpoint.com/v2/url?u=https-3A__gist.github.com_manovotn_b9e9fde25ab77b5e481d5b34edf02b0c-23file-2Dconversationbean-2Djava-2DL10-2DL16&d=DwICaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=hl8XiFr1UrTSgyXVc4KO_i51sM3Gyhlu1KZ4TkyseEQ&m=uvdQf1sxR6VmxxDyV0JaOkEISRIJR3-N8dd2BXxazMQ&s=sjRD4J8rN0Vi9ZLoAC6sQ9x0WiJ96YjwVmefVelXceU&e= 

----- Original Message -----
> From: "Benjamin Confino" <BENJAMIC at uk.ibm.com>
> To: "Matej Novotny" <manovotn at redhat.com>
> Cc: "Takayuki T Ishii" <EBB0F3L at jp.ibm.com>, weld-dev at lists.jboss.org
> Sent: Tuesday, January 28, 2020 12:06:14 PM
> Subject: RE: [weld-dev] Question about conversations scope initilization 
         obeserver
> 
> Hello
> 
> Thanks for the link. I had a look but I couldn't find any TCK tests
> checking to see if an observer method will catch the new
> ConversationContext being created for the "new transient conversation". 
To
> check if a new conversation was activated I created an entirely fresh
> server and ran the test application on it, the behaviour was the same, 
the
> first url I pinged on this new server ended with "cid=" and the observer
> didn't . Normally I've just been restarting the old server but 
restarting
> frequently.
> 
> I've attached the recreate you requested. it consists of the three 
classes
> attached to my previous email as well as a minimal html page. To run it
> load it onto your server and ping
> 
https://urldefense.proofpoint.com/v2/url?u=http-3A__localhost-3A9080_ConversationContextTest_index.xhtml&d=DwICaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=hl8XiFr1UrTSgyXVc4KO_i51sM3Gyhlu1KZ4TkyseEQ&m=uvdQf1sxR6VmxxDyV0JaOkEISRIJR3-N8dd2BXxazMQ&s=OvJ-n1itv_FHZczFGtGTVn8L-4U7bv921PgvTBYisfA&e= 
 to see the
> observer fire, and
> 
https://urldefense.proofpoint.com/v2/url?u=http-3A__localhost-3A9080_ConversationContextTest_index.xhtml-3Fcid-3D99999&d=DwICaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=hl8XiFr1UrTSgyXVc4KO_i51sM3Gyhlu1KZ4TkyseEQ&m=uvdQf1sxR6VmxxDyV0JaOkEISRIJR3-N8dd2BXxazMQ&s=IUIJSEejwSp_M36ux_W_THun4lDX62tuS5uT76Pq1N4&e= 
 to see
> the observer fail to fire.
> 
> Best regards
> Benjamin
> 
> 
> 
> From:   Matej Novotny <manovotn at redhat.com>
> To:     Benjamin Confino <BENJAMIC at uk.ibm.com>
> Cc:     weld-dev at lists.jboss.org, Takayuki T Ishii <EBB0F3L at jp.ibm.com>
> Date:   27/01/2020 11:39
> Subject:        [EXTERNAL] Re: [weld-dev] Question about conversations
> scope initilization     obeserver
> 
> 
> 
> Hello,
> 
> I'd start by pointing you to CDI TCK as that's a good starting point to
> see what's covered.
> For your question, that would be this test -
> 
https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_eclipse-2Dee4j_cdi-2Dtck_blob_master_impl_src_main_java_org_jboss_cdi_tck_tests_context_conversation_ClientConversationContextTest.java-23L344-2DL349&d=DwICaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=hl8XiFr1UrTSgyXVc4KO_i51sM3Gyhlu1KZ4TkyseEQ&m=LuqfrtLLuJH86SKffsaBnDrxGJkBeoRqjz2EMS6K9mM&s=EO58wz7fGAjoo_qGMInGkEU8QMORj_W6IiAR-CM1WF4&e=

> 
> And possibly few more in the same test class.
> 
> As for the linked classes - your `ConversationBean` is listening for
> @Initialized event. Can you verify that a new conversation was activated
> for your request instead of verifying that context was activated?
> E.g. check IDs or something along those lines? I suppose that will hold
> true and in that case it works just as spec requires it to.
> From the top of my head I don't really know how we activate/deactivate
> ConversationContext, I'd need to dig that up, but looking at CDI spec, 
it
> doesn't mandate that it is activated every time again and it could 
already
> be active for given request.
> Plus from just the classes you linked, I cannot know if you test this 
with
> no existing conversation or maybe with some long running one before you
> try to send a request for non-existing one...and so on.
> So if the above doesn't is not enough to answer your question, then 
we're
> going to need a complete reproducer so that we both talk about the same
> scenario :)
> 
> Matej
> 
> ----- Original Message -----
> > From: "Benjamin Confino" <BENJAMIC at uk.ibm.com>
> > To: weld-dev at lists.jboss.org
> > Cc: "Takayuki T Ishii" <EBB0F3L at jp.ibm.com>
> > Sent: Monday, January 27, 2020 11:42:14 AM
> > Subject: [weld-dev] Question about conversations scope initilization
> obeserver
> > 
> > Hello
> > 
> > I have a customer who's sent me a sample application, I have attached
> the
> > source to it below.
> > 
> > When the customer visits index.xhtml they see the following output:
> > 
> > Conversation initialized.
> > Conversation begun. cid:1 , timeout:3600000
> > Conversation destroyed. cid:1
> > 
> > However when they append "?cdi=" or a non-existnant identifier like
> > "?cdi=10000" to the url they do not see "Conversation initialized."
> > 
> > The CDI spec says that: If the propagated conversation cannot be
> restored,
> > the container must associate the request with a new transient
> conversation
> > and throw an exception of type
> > javax.enterprise.context.NonexistentConversationException.
> > 
> > I'm wondering if this should apply here? Or would it only apply if the
> cid
> > pointed to an existing conversation that could not be restored? And is
> there
> > anything in the spec that covers this specific situation?
> > 
> > Unless stated otherwise above:
> > IBM United Kingdom Limited - Registered in England and Wales with 
number
> > 741598.
> > Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
> 3AU
> > 
> > _______________________________________________
> > weld-dev mailing list
> > weld-dev at lists.jboss.org
> > 
> 
https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.jboss.org_mailman_listinfo_weld-2Ddev&d=DwICaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=hl8XiFr1UrTSgyXVc4KO_i51sM3Gyhlu1KZ4TkyseEQ&m=LuqfrtLLuJH86SKffsaBnDrxGJkBeoRqjz2EMS6K9mM&s=ptwSTb9inzN42wgy9ctxUbuZO9ho6NYWekXQCURzWL4&e=

> 
> 
> 
> 
> 
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 
3AU
> 

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
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