[weld-dev] ApplicationScoped event fires on service invocation

[Martin Kouba]

Hi Benjanmin,

for a web application the payload of 
@Initialized(ApplicationScoped.class) must be the relevant 
ServletContext. That's why Weld is waiting for a webapp to be ready 
(implemented as 
javax.servlet.ServletContextListener.contextInitialized(ServletContextEvent)).

Martin

Dne 19.8.2016 v 14:17 Benjamin Confino napsal(a):
> We have a user scenario where we wishes to replace @Singleton @Startup
> EJB beans with CDI beans. This was attempted by observing the
> ApplicationScoped initialization event to trigger the replacement code.
>
> However, the event was fired only after the service invocation, which
> was too late. Apparently OWB fires this event much earlier.
> The CDI spec states:
>
> The /application context /is provided by a built-in context object for
> the built-in scope type
> @ApplicationScoped. The application scope is active:
> • during the service() method of any servlet in the web application,
> during the doFilter()
> method of any servlet filter and when the container calls any
> ServletContextListener,
> HttpSessionListener, AsyncListener or ServletRequestListener,
> • during any Java EE web service invocation,
> • during any remote method invocation of any EJB, during any
> asynchronous method invocation
> of any EJB, during any call to an EJB timeout method and during message
> delivery to any EJB
> message-driven bean,
> • when the disposer method or @PreDestroy callback of any bean with any
> normal scope other
> than @ApplicationScoped is called, and
> *• during **@PostConstruct **callback of any bean.*
>
> The application context is shared between all servlet requests, web
> service invocations, EJB
> remote method invocations, EJB asynchronous method invocations, EJB
> timeouts and message
> deliveries to message-driven beans that execute within the same
> application. The application
> context is destroyed when the application is shut down.
>
> An event with qualifier @Initialized(ApplicationScoped.class) is fired
> when the application
> context is initialized and an event with qualifier
> @Destroyed(ApplicationScoped.class) is fired
> when the application is destroyed. The event payload is:
> • the ServletContext if the application is a web application deployed to
> a Servlet container, or
> • any java.lang.Object for other types of application.
>
> How do you interpret "initialized"? Does it mean the event is fired only
> after the context is *active?*
>
> Is it possible to make the event firing a bit earlier, say around
> AfterDeploymentValidation?
>
> Below is the app to demonstrate the timing along with the server.xml:
>
>
>
>
> And here is the results of running it
>
>
> [AUDIT   ] CWWKE0001I: The server defaultServer has been launched.
> [AUDIT   ] CWWKE0100I: This product is licensed for development, and
> limited production use. The full license terms can be viewed here:
> https://public.dhe.ibm.com/ibmdl/export/pub/software/websphere/wasdev/license/base_ilan/ilan/16.0.0.2/lafiles/en.html
>
> [AUDIT   ] CWWKZ0058I: Monitoring dropins for applications.
> *---> ApplicationScopedExtension, AfterDeploymentValidation event
> received, before looking up and touching @ApplicationScoped dummy bean*
> *---> ApplicationScopedDummyBean, @PostConstruct init method called*
> *---> ApplicationScopedExtension, after looking up and touching
> @ApplicationScoped dummy bean*
> [AUDIT   ] CWWKT0016I: Web application available (default_host):
> http://localhost:9080/70383.180.846.test-application/
> *---> ApplicationScopedObserverBean, observed
> @Initialized(ApplicationScoped.class) event.*
> [AUDIT   ] CWWKZ0001I: Application 70383.180.846.test-application
> started in 1.165 seconds.
> [AUDIT   ] CWWKF0012I: The server installed the following features:
> [jsp-2.3, ejbLite-3.2, managedBeans-1.0, jsf-2.2, beanValidation-1.1,
> servlet-3.1, ssl-1.0, jndi-1.0, jsonp-1.0, appSecurity-2.0, jdbc-4.1,
> jaxrs-2.0, jaxrsClient-2.0, el-3.0, json-1.0, cdi-1.2,
> distributedMap-1.0, webProfile-7.0, websocket-1.1, jpa-2.1].
> [AUDIT   ] CWWKF0011I: The server defaultServer is ready to run a
> smarter planet.
>
> As you can see, the *ApplicationScopedDummyBean, @PostConstruct init
> method called*proves that the applicationContext was active before the
> event was fired. Why is this applicationscoped initialization event not
> fired earlier?
>
>
> Regards
> Benjamin
> 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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>

-- 
Martin Kouba
Software Engineer
Red Hat, Czech Republic