[weld-dev] Interceptors

[Martin Kouba]

Dne 13.5.2015 v 00:27 Emily Jiang napsal(a):
> Thank you Jozef for the helpful info. I have another question on
> interceptor:
> EE7 spec states the JavaEE component classes, listed in Table EE.5-1,
> need to support interceptors. Take servlet for an example, which methods
> can be intercepted?
>
> As the servlet classes are invoked by the container, according to CDI1.2
> spec, it seems only service(ServletRequest, ServletResponse) can be
> intercepted. No other methods can be intercepted.
>
> Normally customer applications override doPost or doGet, but they cannot
> be intercepted. I cannot see any value of support interceptors on
> Servlet. Anything I missed?

The serlet container always invokes Servlet.service(ServletRequest, 
ServletResponse)() which delegates to one of those convenient methods 
(doGet() etc.) in case of javax.servlet.http.HttpServlet. So if you 
extend HttpServlet and only override doGet() it would be "intercepted" 
if you annotate the servlet class with an interceptor binding. If you 
only annotate the doGet() method an interceptor will not be invoked.

>
> On Tue, May 12, 2015 at 7:50 AM, Jozef Hartinger <jharting at redhat.com
> <mailto:jharting at redhat.com>> wrote:
>
>     On 05/11/2015 03:47 PM, Emily Jiang wrote:
>>
>>     I have a few questions on interceptors:
>>
>>     1. CDI Interceptors on cdi beans
>>     Will the interceptors share the same creational context as the
>>     bean it is associated with?
>     Yes. It is not the very same creational context but a new one with a
>     parent-child relationship to the one of the associated bean. This is
>     the same as for @Dependent dependencies
>>     Will Weld managed the cdi interceptors as well as the old-styled
>>     interceptors?
>     Yes, Weld manages interceptor bindings associated using interceptor
>     bindings as well as those associated using @Interceptors
>>     @Interceptors don't work on other cdi beans except ejb and managed
>>     beans, right?
>     "Managed bean" is ambiguous. Weld support interceptors on all CDI
>     managed beans (not on producer fields/methods nor extension-provided
>     beans).
>>
>>     2. Interceptors on ejb beans or managed beans
>>     I think the integrator needs to create these @Interceptors and cdi
>>     interceptors.
>     Yes, for EJBs and EE managed beans it is integrator's job to handle
>     those. Weld can handle @AroundConstruct interceptors if needed. I've
>     updated the docs on this topic recently:
>     https://github.com/jharting/core/blob/a1eb6194be36ded86dc9709c6767f5016fb98997/docs/reference/src/main/asciidoc/ri-spi.asciidoc#around-construct-interception
>>     Will these interceptors use the non-contextual creational context
>>     (scope @Dependent) or use the ejb or managed bean's creational
>>     context?
>     ejb or managed bean's creational context
>>
>>     Will Weld destroy the interceptors when the associated beans are
>>     destroyed or the integrator need to destroy them? This logic
>>     applicable to both cdi interceptors and @Interceptors style
>>     interceptors, right?
>     Any time the parent (bean's) creational context is destroyed, the
>     children creational contexts (interceptors') are destroyed also by Weld.
>>
>>     3. Interceptors on JavaEE components
>>     I think this interceptors are created by Weld when the JavaEE
>>     component classes are created, right? By the way, how can the
>>     container make sure to destroy the interceptors?
>     This depends on how the component classes are managed. Assuming the
>     components are managed using Weld-provided InjectionTarget then it
>     is up to the integrator to decide whether it provides interception
>     support or whether it should be provided by Weld. This can be
>     configured for each InjectionTarget individually using this builder:
>     http://docs.jboss.org/weld/javadoc/2.2/weld-spi/org/jboss/weld/manager/api/WeldInjectionTargetBuilder.html
>>
>>
>>     --
>>     Thanks
>>     Emily
>>     =================
>>     Emily Jiang
>>     ejiang at apache.org <mailto:ejiang at apache.org>
>>
>>
>>     _______________________________________________
>>     weld-dev mailing list
>>     weld-dev at lists.jboss.org  <mailto:weld-dev at lists.jboss.org>
>>     https://lists.jboss.org/mailman/listinfo/weld-dev
>
>
>
>
> --
> Thanks
> Emily
> =================
> Emily Jiang
> ejiang at apache.org <mailto:ejiang at apache.org>
>
>
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