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From Gordon Sim <g...@redhat.com>
Subject Re: Subject Filtering with Queues
Date Fri, 06 Jun 2014 13:25:55 GMT
On 06/06/2014 02:17 PM, Fraser Adams wrote:
> Gordon,
> Re "However, I am not sure whether the selector can select on the
> subject/routing-key"
> The spout and drain examples I posted earlier actually do work (using
> qpidd, I've not tried it with the Java Broker to be fair), but those
> were examples using AMQP 0.10
> e.g.
> ./drain -b localhost -f \
> "queue1; {create: receiver, link: {name: test-link, selector:
> \"qpid.subject='tim'\"}}"
> as you can see this is specifying a selector testing the qpid.subject
> property equals tim, which in AMQP 0.10 gets set automagically when I do
> ./spout -b localhost --content "Hello World" "queue1/tim"
> Because the subject (in AMQP 0.10) actually gets automagically mapped to
> qpid.subject (essentially an application property) this all does
> actually hang together with AMQP 0.10 using qpidd and qpid::messaging
> without "any handling of that as a special value"

Right, my point was your are matching against the qpid.subject 
application property which is populated automatically by qpid messaging 
clients (but wouldn't necessarily be for others, not sure what the 0-10 
JMS client does for example).

> With AMQP 1.0 subject is an "immutable property" not an "application
> property" so uses its own accessor (you of course know this better than
> most :-)) so would need some code in the selector implementation to
> explicitly expose it for matching.

Right, and at present that isn't there as far as I can tell (though I 
may just be missing it).

> You might well be right that the JavaBroker would reject this as invalid
> as a selector, I've been bitten by my use of hyphens in property names
> being rejected, but the qpid.subject definitely worked for me the last
> time I tried it on qpidd.

Ah yes, it was hyphens you had mentioned. I suspect the '.' may also be 
a problem, since its not a valid char in a java identifier.

> Although not part of the JMS selector specification I do actually think
> that being able to use the subject as a pseudo-property for message
> selectors is pretty useful and something that I suspect most people
> might "intuitively" expect to be able to do.

I very much agree.

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