[infinispan-dev] singleton @Listeners

[Mircea Markus]

----- Original Message -----
> From: "Galder Zamarreño" <galder at redhat.com>
> To: "infinispan -Dev List" <infinispan-dev at lists.jboss.org>
> Sent: Friday, July 6, 2012 2:46:20 AM
> Subject: Re: [infinispan-dev] singleton @Listeners
>
>
> On Jun 28, 2012, at 11:26 AM, Mircea Markus wrote:
>
> > This is a problem that pops up constantly:
> > User:      "I add a listener to my distributed/replicated cache but
> > this gets invoked numOwners times - can I make that to be invoked
> > only once cluster wise?"
> > Developer: "Yes, you can! You have to do that and that..."
> >
> > What about a "singleton" attribute on the Listener? Would make the
> > reply shorter:
> > Developer: "Use @Listener(singleton=true)"
>
> Hmmm, that seems doable without any extra attributes.
>
> For a replicated cache, take the view and pick a node (consistently
>
> For a distributed cache, find the primary owner of a key.
That's pretty much how I had in mind to implement it. But I think the attribute is needed though: there are use cases in which you still want to be notified on all the owners, as you do now. OTOH if you only want a per-cluster notification you'd add this attribute to the listener.
>
> Has this been asked so often? I don't recall right now… :)
Yes, CBOE had the same issue as they needed to push updates from one cluster to the other over hotrod.
Also in this article they have to do quite a workaround to enforce uniqueness:  blog.c2b2.co.uk/2012/06/infinispan-event-push-to-tomcat.html
And there were some others :)

>
> >
> > Cheers,
> > Mircea
> >
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>
> --
> Galder Zamarreño
> Sr. Software Engineer
> Infinispan, JBoss Cache
>
>
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