[jboss-as7-dev] Add Notification support to the domain management API

[Heiko Braun]

It makes sense if we speak about async callbacks to notification handlers. But for the polling based approached you described, there will be time T between each client poling for notifications. Now if notifications are not kept (persisted somehow, memory or otherwise) for that window clients will miss them. That's the TTL i was talking about. 


On Feb 26, 2013, at 1:09 PM, Jeff Mesnil <jmesnil at redhat.com> wrote:

> 
> Le 25 févr. 2013 à 17:47, Heiko Braun <hbraun at redhat.com> a écrit :
>> Do notification types have different TTL's? (i.e. MOTD)
> 
> I don't think that a TTL makes sense for a notification.
> 
> A notification is just a description of an event that *already occurred*. The only meaningful date you have is the timestamp of the notification (that is an approximation of the time when the event that triggered the notification occurred).
> 
> Let's take the example of resources added/removed.
> If you receive a notification RESOURCE_ADDED for the resource A with the timestamp T, the only thing you know for sure is that the resource was added at that time.
> But this does not mean that the resource still exists when you handle the notification if it has been removed in the meantime. Even in that case, the notification is still exact and you will eventually receive a RESOURCE_REMOVED notification later on in that case.
> 
> Receiving notifications trough polling or push notifications does not change that: you only receive notifications after the event occurred and you can only react to the past.
> 
> Does that make sense?
> 
> -- 
> Jeff Mesnil
> JBoss, a division of Red Hat
> http://jmesnil.net/
>