On 05/19/2014 04:25 PM, Rafael Schloming wrote:
FWIW I tend to think using subscribe in that way is really a bit of an anti-pattern because it imposes a strict ordering requirement on the startup sequence of the various distributed components in the system. To be specific, you always have to start the broker first, the subscriber second, and the publisher third.
No, I don't think that is the case. Consider a discovery case, where there are many 'agents' up and running, and some component wants to get a list of them.
One common solution is to subscribe to some topic on which agents advertise themselves, then send a request that every agent re-announce themselves. (E.g as in the reservations example for the qpid.messaging client).
If you can be sure that the subscription is active before you send your request, you may miss announcements. So while you do indeed want to start the publisher (of the request) before the subscriber (to the announcement), these are in the same process.
--------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
