[Design of JBoss ESB] - Re: Features of JBoss Messaaging Message Bridge present in E
by dsmiley
In my case, neither end of the queues are a JBoss Messaging implementation but I'm not convinced at all that even in that case, it settles the issue.
What will happen in the ESB if the destination queue is unavailable or the ESB crashes suddently? Obviously some error and/or exception would end up being logged but what would the state of the service & message be? This is where those QoS options for the bridge come in and I don't know which, in-effect, are the case for the ESB. If the ESB acknowledges message from the JMS gateway before any action processing begins, then your are offering QOS_AT_MOST_ONCE semantics. A quick look at JmsEndpoint.java suggests to me that is what is happening but I'd appreciate confirmation on this matter from JBoss. If you don't acknowledge until the service is done, then you are offering QOS_DUPLICATES_OK semantics. That in particular is the level I'd like if I could get it but it appears I'm SOL for now. Finally, if you do the whole thing under JCA then you offer QOS_ONCE_AND_ONLY_ONCE. I see that there are configuration options reflecting that the JMS gateway is transacted, but there appears to be no follow-through in the JMSRouter to get an end-to-end transaction. I'm not an expert on this matter so perhaps it's really there but I just don't know it.
For my needs... I definitely don't want the message being lost.
A related question i have is what if an action produces an exception... what happens then? I'm hoping there's some built-in retry mechanism.
This is something that should be prominently documented because it's an important matter for enterprise middle ware, IMO.
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16 years, 3 months