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From Andreas Gies <>
Subject Re: Advisory Messages -- None for Unsubscribe Durable from Topic? (etc)
Date Tue, 28 Apr 2009 06:19:10 GMT
Hi there,

you can browse the AdvisorySupport class and navigate from there to  
which objects are used to create the Advisory messages.

This having said, the architecture sounds a bit strange to me. One  
reason why you use
JMS is to decouple producers and consumers. If I understand correctly  
you are trying
to couple the producer to the fact that at least one  consumer for a  
particular topic exists.

In a publish/subscribe architecture normally a producer publishes  
events - important events
persistently and notifications non-persistently. The producer doesn't  
(shouldn't) really care
who is connected on the consumer side.

My 2 ct

On Apr 28, 2009, at 3:23 AM, dlindquist wrote:

> I've been playing with the advisory messages in ActiveMQ --  
> primarily for the
> purpose of avoiding doing the work to build a message if no-one is  
> listening
> on the topic, but also for monitoring clients.
> The advisory messages work great for this, but I seem to be missing  
> where to
> find a couple of advisory messages...
> First, I can't seem to find any message for when someone  
> unsubscribes from a
> topic (when using a durable connection).  This is a bit annoying,  
> because it
> means that I receive NO notification at all when a durable subscriber
> decides to no longer receive messages.
> Secondly, when I START receiving advisory messages, I get a nice  
> 'flood'
> that fills me in on who is listening, even if they've connected long  
> ago --
> this is great, because I don't miss anything that happened while I was
> 'away'.  Unfortunately, I only receive this type of 'catchup'  
> message for
> durable subscribers if they are currently ACTIVELY CONNECTED.  I don't
> receive anything if they are currently not connected (but are still
> 'receiving' messages anyway, because they are 'durable').
> And lastly, I can determine the subscriber ID of any subscriber  
> (including
> durables), but I can't seem to determine the CLIENT ID, even though  
> this
> seems to be an important part of a durable subscription (ie, the  
> durable
> subscriber is identified by BOTH the client id AND the subscriber id).
> Is there any way for me to determine any of these?  Or am I trying to
> completely bastardize ActiveMQ? ;-)
> TIA!
> -- 
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