Good point. Should this be addressed at the platform level?
-marina
Carlo de Wolf wrote:
> I wish to challenge the assumptions made in
> http://www.adam-bien.com/roller/abien/entry/how_to_pass_context_with.
> Not because it looks like a bad pattern, but more because it relies on
> un(der)specified behavior.
>
> Summary of the article: Context between EE layers can be passed via
> ThreadLocal.
>
> The one piece I can find in the spec only implies this behavior:
> EJB 3.1 FR 4.8.5:
> "That is, where an outbound call from a Singleton method results in a
> loopback call to the Singleton on the same thread."
>
> Given an invocation on a local view the assumption is pretty solid.
> Assuming that there is no ThreadLocal possible in a remote invocation
> coming from another VM is very solid.
>
> The weakness comes when two EARs are deployed and one calls the other
> via a remote view.
> Would this be a same thread invocation or not?
> If so, deploying the EARs on different VMs would change the semantics
> of the remote view invocation (while still being a valid assembly).
>
> So I would like to see the answers to the following be put into spec:
> - does a local view invocation imply a call on the same thread?
> - does a remote view invocation imply a call on the same thread?
>
> My answers would be: yes, no.
>
> In short: A container may or may not process a remote view invocation
> on the same thread. A portable application *must not* rely on the
> thread context of such an invocation. Local view invocation are always
> processed on the same thread.
>
> Carlo