[seam-issues] [JBoss JIRA] Commented: (SEAMCRON-6) Can we use @RequestScoped for @Scheduled and @Asynchronous methods? How?
Martin Kouba (JIRA)
jira-events at lists.jboss.org
Wed Aug 10 08:32:48 EDT 2011
[ https://issues.jboss.org/browse/SEAMCRON-6?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12619990#comment-12619990 ]
Martin Kouba commented on SEAMCRON-6:
I'm not sure about conversation scope, but request scope seems to me legal and pretty useful (in terms of reusing request scoped components) for both @Scheduled and @Asynchronous methods.
In Seam Cron quartz impl or custom quartz integration this could be accomplished e.g. with org.quartz.JobListener and org.jboss.weld.context.bound.BoundRequestContext (http://docs.jboss.org/weld/reference/1.1.0.Final/en-US/html/contexts.html).
> Can we use @RequestScoped for @Scheduled and @Asynchronous methods? How?
> Key: SEAMCRON-6
> URL: https://issues.jboss.org/browse/SEAMCRON-6
> Project: Seam Cron
> Issue Type: Task
> Reporter: Peter Royle
> Assignee: Peter Royle
> Fix For: 3.0.0.Alpha2
> This is one for investigation some time. It came up in this IRC chat:
> The weld reference document (page 34) states:
> The request and application scopes are also active:
> • during invocations of EJB remote methods,
> • during invocations of EJB asynchronous methods,
> • during EJB timeouts,
> • during message delivery to a message-driven bean,
> • during message delivery to a MessageListener, and
> • during web service invocations.
> So we should be able to support this, even if only for certain providers (ie: EJB)
> IRC Transcript:
> [11:10am] johnament: request scoped won't be active in a background thread.
> [11:10am] PeteRoyle: ah true cos it's threadlocal?
> [11:10am] johnament: which?
> [11:11am] PeteRoyle: request scoped implementation
> [11:11am] PeteRoyle: won't work in a background thread because the implementation of request scope uses threadlocal, is that right?
> [11:11am] johnament: its essentially an HTTP request
> [11:12am] PeteRoyle: right
> [11:12am] PeteRoyle: I think the use case is valid though, do you agree?
> [11:13am] johnament: its valid, but it breaks the CDI model, so to say
> [11:13am] johnament: because you want to make your contextual objects available outside of your context
> [11:14am] PeteRoyle: right yeah that makes sense
> [11:14am] PeteRoyle: the request might be over
> [11:14am] johnament: the only thing really available is going to be dependent or application scoped
> [11:15am] johnament: the bigger question - which request?
> [11:15am] PeteRoyle: well the one from which the @Asynch method was called - assuming we could hang onto it
> [11:15am] PeteRoyle: hang onto the request that is
> [11:16am] PeteRoyle: eg: a controller which @Injects a @RequestScoped Thing, then calls an @Asynchronous method
> [11:17am] johnament: the only way it would work is to make request scope extend through your @asynch process is over.
> [11:18am] PeteRoyle: The interceptor would have access to the correct @RequestScope. It would need to replicate it into the new thread. Would that be possible do you think?
> [11:18am] johnament: i don't know how plausible/possible that even is.
> [11:18am] PeteRoyle: yeah. I might leave that as something for investigation later. I'll JIRA it
> [11:18am] johnament: jms does this by transporting the event over JMS, but loses the context.
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