Hi Martin,
My comments in blue.

Many thanks,
Emily
===========================
Emily Jiang
WebSphere Application Server Liberty Profile development, CDI Development Lead
 
MP 211, DE3A20, Winchester, Hampshire, England, SO21 2JN
Phone:  +44 (0)1962 816278  Internal: 246278

Email: emijiang@uk.ibm.com
Lotus Notes: Emily Jiang/UK/IBM@IBMGB



From:        Martin Kouba <mkouba@redhat.com>
To:        Emily Jiang/UK/IBM@IBMGB,
Cc:        cdi-dev-bounces@lists.jboss.org, cdi-dev@lists.jboss.org
Date:        10/08/2015 07:52
Subject:        Re: [cdi-dev] Clarification on the difference on Vetoed and exclude filters regarding Java EE component classes
Sent by:        cdi-dev-bounces@lists.jboss.org



Dne 7.8.2015 v 10:29 Emily Jiang napsal(a):
> Thanks Martin for your reply! Your reply confirmed my understanding of
> @Vetoed.
>
> What is the expected behaviour if I exclude my JavaEE component class in
> the filter under beans.xml? Will this cause the JavaEE component class
> being ignored by CDI or this should have the same effect as being
> annotated as @Vetoed?

This should have the same effect as @Vetoed.
<ej>
In this case, the session 12.4.1 Type discovery should be enhanced,

that is not excluded from discovery by an exclude filter as defined in Section 12.4.2, “Exclude
filters”.

should be changed to

that is not excluded from discovery by an exclude filter as defined in Section 12.4.2, “Exclude
filters”or annotated with @Vetoed (class level or package level).
<ej>
>
> "In the 12.4.2, it states: If the filter is active, and: .... then we
> say that the type is excluded from discovery."
>
> Does the above discovery mean both type and bean discovery or just bean
> discovery? If it means both type and bean discovery, the classes should
> be ignored by CDI. Please confirm.

@Veto, ProcessAnnotatedType.veto() and exclude filters are tied to Type
discovery. Moreover, the Java EE components (like servlets) are not CDI
beans and may not be vetoed at all.
<ej>
I think the @Vetoed is useful in the explicit bean discovery mode to exclude the JavaEE component classes from considering as beans. In the implicit bean archive, they are not beans anyway.

I have still further question on the following spec sections.


12.4.1. Type discovery
First the container must discover types. The container discovers:
• each Java class, interface (excluding the special kind of interface declaration annotation type)
or enum deployed in an explicit bean archive, and
• each Java class with a bean defining annotation in an implicit bean archive.
• each session bean
that is not excluded from discovery by an exclude filter as defined in Section 12.4.2, “Exclude
filters”.
12.4.3. Bean discovery
For every type in the set of discovered types (as defined in Section 12.4.1, “Type discovery”), the
container must:
• inspect the type metadata to determine if it is a bean or other Java EE component class
supporting injection, and then
• detect definition errors by validating the class and its metadata, and then
• if the class is a managed bean, session bean, or other Java EE component class supporting
injection, fire an event of type ProcessInjectionPoint for each injection point in the class, as
defined in Section 11.5.7, “ProcessInjectionPoint event”, and then
• if the class is a managed bean, session bean, or other Java EE component class supporting
injection, fire an event of type ProcessInjectionTarget, as defined in Section 11.5.8,
“ProcessInjectionTarget event”, and then


The Bean discovery stage seems to suggest it only consider the types discovered in the type discovery. Considering a @Vetoed JavaEE component class or such class in an implicit bean archive, it won't be processed in the bean discovery stage as it opts out from type discovery. Neither processInjectionPoint nor ProcessInjectionTarget events can be fired. I think it is wrong.


Another query: would the Spec require JavaEE component classes to support injection in an non bean archive?
</ej>
>
> Many thanks,
> Emily
> ===========================
> Emily Jiang
> WebSphere Application Server Liberty Profile development, CDI
> Development Lead
>
> MP 211, DE3A20, Winchester, Hampshire, England, SO21 2JN
> Phone:  +44 (0)1962 816278  Internal: 246278
>
> Email: emijiang@uk.ibm.com
> Lotus Notes: Emily Jiang/UK/IBM@IBMGB
>
>
>
>
> From: Martin Kouba <mkouba@redhat.com>
> To: Emily Jiang/UK/IBM@IBMGB, cdi-dev@lists.jboss.org,
> Date: 07/08/2015 03:40
> Subject: Re: [cdi-dev] Clarification on the difference on Vetoed and
> exclude filters regarding Java EE component classes
> Sent by: cdi-dev-bounces@lists.jboss.org
> ------------------------------------------------------------------------
>
>
>
> Dne 6.8.2015 v 15:55 Emily Jiang napsal(a):
>  > In the section 3.6. Java EE components of CDI 1.2 specification, it has
>  > the following statement:
>  >
>  > /It is safe to annotate Java EE components with //@Vetoed //to prevent
>  > them being considered beans./
>  >
>  > According to my understanding, the JavaEE component classes with @Vetoed
>  > should still support injections and *ProcessInjectionTarget*events
>  > should still be fired.
>  >
>  > In the 12.4.2, it states:
>  > /If the filter is active, and: .... then we say that the type is
>  > excluded from discovery./
>  >
>  > Does this mean if a JavaEE component class is excluded from the scan in
>  > the beans.xml, its CDI involvement should be ignored (@Inject would be
>  > ignored etc)?
>
> I don't think so. I believe the intent of "3.6. Java EE components" is
> to clarify that if a component class (e.g. a servlet class) is also
> recognized as a managed bean [1] there will be two different
> "components" in your applicaion, each managed by a different Java EE
> technology - e.g. a servlet managed by the servlet container and a CDI
> bean with servlet class in its set of bean types.
>
> The servlet has a different lifecycle, it's managed by a servlet
> container and as such must support injection (but cannot be injected, etc.).
>
> This might be confusing and therefore it's a good idea to veto the Java
> EE component classes -> there will be no CDI bean definitions based on
> the component classes.
>
> [1]
> http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#what_classes_are_beans
>
>
>  >
>  > Many thanks,
>  > Emily
>  > ===========================
>  > Emily Jiang
>  > WebSphere Application Server Liberty Profile development, CDI
>  > Development Lead
>  >
>  > MP 211, DE3A20, Winchester, Hampshire, England, SO21 2JN
>  > Phone:  +44 (0)1962 816278  Internal: 246278
>  >
>  > Email: emijiang@uk.ibm.com
>  > Lotus Notes: Emily Jiang/UK/IBM@IBMGB
>  >
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> --
> Martin Kouba
> Software Engineer
> Red Hat, Czech Republic
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--
Martin Kouba
Software Engineer
Red Hat, Czech Republic
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Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU