Hi, I'm trying to implement the following simple pattern using ActiveMQ: - my server maintains a "state" - my clients connect to the server, get a snapshot of the state and suscribe to updates of the state
So I need the "state snapshot + subscription" step to be atomic for each client connecting to the updates topic. So far the only solution I can think of is: - put an absolute sequence number on update messages - use separate temporary queues for state snapshot requests (like described here: http://activemq.apache.org/how-should-i-implement-request-response-with-jms.html ) - each state snapshot is tagged with the sequence number of the corresponding update - when a client connects, it suscribes first to the updates topic, then requests the snapshot state, and just discards updates that are older than the snapshot state I feel there might be a smarter solution, as strict ordering is built in the framework ? Or maybe using advisory messages ? Thanks, Julien
