How do you link gateway channels to non-gateway channels?

[karypid]

Hello,

This is a rather simple newbie question regarding JBossESB.

I understand that JBossESB gateway listeners convert incoming messages to JBossESB's internal format (defined in message.xsd) and then forward them to "ESB-aware" channels.

As far as I can see, services must have at least one ESB-aware listener. Otherwise deployment fails with JBossESB complaining about the lack of an ESB-aware listener. So far so good.

Now, in the jboss-esb.xml file, the only thing I'm aware of that links the gateway listeners to the non-gateway listener is the fact that they are declared within the "listeners" element as follows:

<listeners>
 <sql-listener name="SQL-Gateway"
 busidref="mySQLChannel"
 is-gateway="true"
 poll-frequency-seconds="5" />
 <fs-listener name="FS-Gateway"
 schedule-frequency="5"
 is-gateway="true"
 busidref="myFilesystemChannel" />
 <jms-listener name="JMS-Gateway"
 busidref="quickstartGwChannel" is-gateway="true" />
 <jms-listener name="helloWorld"
 busidref="quickstartEsbChannel" />
</listeners>

So, my assumption is that all non-gateway listeners forward their message to the esb-aware listener alongside which they are defined. Is that correct?

In any case, I tried to define two ESB-aware listeners (as follows) and found out that JBossESB does not complain:

<listeners>
 <sql-listener name="SQL-Gateway"
 busidref="mySQLChannel"
 is-gateway="true"
 poll-frequency-seconds="5" />
 <fs-listener name="FS-Gateway"
 schedule-frequency="5"
 is-gateway="true"
 busidref="myFilesystemChannel" />
 <jms-listener name="JMS-Gateway"
 busidref="quickstartGwChannel" is-gateway="true" />
 <jms-listener name="helloWorld"
 busidref="quickstartEsbChannel" />
 <jms-listener name="helloWorld2"
 busidref="quickstartEsbChannel2" />
</listeners>

I would've expected JBossESB to complain that there are multiple non-gateway listeners defined, but everything worked like a charm.

So, what is the logic behind this? How are the two kinds of listeners associated with each other?

[mike_ap]

I'm not an expert at this but from what I can see, the ESB will load-balance the message across all the ESB-aware listeners.

I setup a Service with a System.Println action, one gateway listener and two ESB-aware listeners. What I noticed is that if I send a bunch messages to the gateway, half of the messages would go the the 1st esb-aware listener and half of the messages would go to the other esb-aware listener.

I'm assuming this functionality is configurable somewhere.