qpid-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Gordon Sim <g...@redhat.com>
Subject Re: how do I retrieve the subject from JMS?
Date Fri, 24 Jun 2011 14:27:09 GMT
On 06/24/2011 03:05 PM, fadams wrote:
> I'm a bit confused.
> Surely the subject has to have been set *somewhere* by the producer, after
> all I'm successfully subscribing to
> "qmf.default.topic/agent.ind.event.org_apache_qpid_broker.#" so the topic
> exchange would be using the subject to apply the binding.
>
> have I missed something???

It is a little confusing. The concept of subject doesn't actually exist 
in AMQP 0-10. There is the concept of a routing-key which is in many 
ways like a subject, especially when using topics. However the exact 
correspondence breaks down a little for queues. Hence we introduced a 
qpid specific variable through which a subject could be carried in a 
message.

So in your case the subscription is being mapped to a binding using a 
particular binding key. Messages received over that binding will have 
the routing key set, but in this case they don't have that special 
subject property set.

We could in these cases (i.e. where there is no qpid.subject) fall back 
to returning the routing key. That might make things less confusing (or 
possibly more?!).

---------------------------------------------------------------------
Apache Qpid - AMQP Messaging Implementation
Project:      http://qpid.apache.org
Use/Interact: mailto:users-subscribe@qpid.apache.org


Mime
View raw message