C How WebLogic MDBs Leverage WebLogic JMS Extensions

The MDB deployment scenarios described in Appendix A, "Topic Deployment Scenarios." take advantage of the following JMS features:

The topicMessagesDistributionMode defines permutations of the JMS attributes SubscriptionSharingPolicy and ClientIdPolicy (set on the connection factory), to control how messages are distributed to distributed topics. WebLogic Server sets those values as shown in Table C-1.

Table C-1 Relationships Between topicMessagesDistributionMode Settings and Settings on JMS Connection Factory

topicMessagesDistributionMode SubscriptionSharingPolicy ClientIdPolicy

One-Copy-Per-Server or One-Copy-Per-Application



Compatibility (replicated distributed topics and foreign topics only)



If the settings on the connection factory are not these values, WebLogic Server overrides them and gives a warning message. If WebLogic Server cannot override the values for any reason, it throws an exception, and the MDB cannot process any messages unless the administrator changes the settings on the JMS connection factory. You cannot programmatically set these attributes on the connection factory directly. Instead, use topicMessagesDistributionMode, and the MDB deployment will set the values on the connection instances.