How to configure MDB as Durable Subscriber

Question

          I can't seem to find any documentation on how to set up an MDB as a Durable Subscriber.
          I tried using the Edit EJB Descriptor link in the console. I then drilled down
          to Message Driven Destination. For Subscription Durability, I selected Durable.
          I clicked Apply. I also went back to the jar and pressed the Persist button to
          "Persist changes made to the Descriptor(s)".
          I check the Topic to see if there were any Durable Subscribers listed. No. I bounced
          the server. Still no.
          What am I missing? The only info I can find in the documentation about setting
          up Durable Subscriptions is via the JMS API (http://e-docs.bea.com/wls/docs61/jms/implement.html#1097632)
          Using WL v6 SP5, not clustered.
          Any help would be appreciated.
          Jim
          

Answer 1

Hi James,
          I'm unfamiliar with the console ejb xml editor. I suggest
          posting to the ejb newsgbroup, which is more familiar
          with these things. Meanwhile, the attached notes
          and the following example may help if your willing
          to hand-edit the xml.
          Tom, BEA
          <ejb-jar>
          <enterprise-beans>
          <message-driven>
          <ejb-name>exampleMessageDrivenA</ejb-name>
          <ejb-class>MessageBean</ejb-class>
          <transaction-type>Container</transaction-type>
          <message-driven-destination>
          <destination-type>javax.jms.Queue</destination-type>
          <!--
          <destination-type>javax.jms.Topic</destination-type>
          <subscription-durability>Durable</subscription-durability>
          -->
          </message-driven-destination>
          </message-driven>
          </enterprise-beans>
          <assembly-descriptor>
          <container-transaction>
          <method>
          <ejb-name>exampleMessageDrivenA</ejb-name>
          <method-name>onMessage()</method-name>
          </method>
          <trans-attribute>Required</trans-attribute>
          </container-transaction>
          </assembly-descriptor>
          </ejb-jar>
          <!-- Sample MessageDriven bean Weblogic deployment descriptor -->
          <weblogic-ejb-jar>
          <weblogic-enterprise-bean>
          <ejb-name>exampleMessageDrivenA</ejb-name>
          <message-driven-descriptor>
          <pool>
          <max-beans-in-free-pool>5</max-beans-in-free-pool>
          <initial-beans-in-free-pool>5</initial-beans-in-free-pool>
          </pool>
          <!--
          <destination-jndi-name>quotestopic</destination-jndi-name>
          -->
          <destination-jndi-name>MDBQ</destination-jndi-name>
          <!--
          <provider-url>t3://localhost:10001</provider-url>
          <connection-factory-jndi-name>cf3</connection-factory-jndi-name>
          <jms-client-id>cid444</jms-client-id>
          -->
          </message-driven-descriptor>
          <jndi-name>someid</jndi-name>
          </weblogic-enterprise-bean>
          </weblogic-ejb-jar>
          James Goodwin wrote:
          > I can't seem to find any documentation on how to set up an MDB as a Durable Subscriber.
          > I tried using the Edit EJB Descriptor link in the console. I then drilled down
          > to Message Driven Destination. For Subscription Durability, I selected Durable.
          > I clicked Apply. I also went back to the jar and pressed the Persist button to
          > "Persist changes made to the Descriptor(s)".
          >
          > I check the Topic to see if there were any Durable Subscribers listed. No. I bounced
          > the server. Still no.
          >
          > What am I missing? The only info I can find in the documentation about setting
          > up Durable Subscriptions is via the JMS API (http://e-docs.bea.com/wls/docs61/jms/implement.html#1097632)
          >
          > Using WL v6 SP5, not clustered.
          >
          > Any help would be appreciated.
          >
          > Jim
          A durable topic subscriber MDB uses its name to generate its client-id.
          Since JMS enforces uniqueness on this client-id, this means that if a durable
          subscriber MDB is deployed to multiple servers only one server will be able
          to connect. Some applications want a different behavior where
          each MDB pool on each server gets its own durable subscription.
          The MDB durable subscription id, which must be unique on its topic, comes from:
          1) <jms-client-id>MyClientID</jms-client-id>
          (the weblogic dtd)
          2) if (1) is not set then the client-id
          comes from the ejb name.
          The durable subscription is uniquely identified within a cluster by a
          combination of "connection-id" and "subscription-id". Only one active
          connection may use a particular "connection-id" within a WebLogic cluster.
          The connection id comes from:
          1) The "ClientId" attribute configured on the WebLogic connection factory.
          This defaults to null. Note that if the ClientId is set on a connection
          factory, only one connection created by the factory
          may be active at a time.
          2) If (1) is not set, then, as with the subscriber-id,
          the connection-id is derived from jms-client-id descriptor attribute:
          <jms-client-id>MyClientID</jms-client-id>
          (the weblogic dtd)
          3) If (1) and (2) are not set, then, as with the subscriber-id,
          the connection-id is derived from the ejb name.
          Work-around:
          A) Create a custom connection-factory for each server:
          1) configure "JNDIName" to the same value across all servers
          ("myMDBCF" in this example)
          2) configure "ClientId" to a unique value per server
          3) enable "UserTransactionsEnabled"
          4) enable "XAConnectionFactoryEnabled"
          5) set "AcknowledgePolicy" to "ACKNOWLEDGE_PREVIOUS"
          6) target the CF at a single WebLogic server
          (Number 5 is required for non-transactional topic MDBs)
          B) In the MDB's weblogic-ejb-jar.xml descriptor, set the MDB's connection
          factory to the JNDI name of the custom connection factories configured in
          (A). Optionally, also specify the subscriber-id via the jms-client-id
          attribute.
          <weblogic-ejb-jar>
          <weblogic-enterprise-bean>
          <ejb-name>exampleBean</ejb-name>
          <message-driven-descriptor>
          <connection-factory-jndi-name>myMDBCF</connection-factory-jndi-name>
          <jms-client-id>myClientID</jms-client-id>
          </message-driven-descriptor>
          </weblogic-enterprise-bean>
          </weblogic-ejb-jar>
          C) Target the application at the same servers that have the custom connection
          factories targeted at them.
          Notes/Limitations:
          1) If the MDB is moved from one server to another, the MDB's corresponding
          connection-factory must be moved with it.
          2) This work-around will not work if the destination is not in the same
          cluster as the MDB. (The MDB can not use the local connection factory, which
          contains the connection-id, as connection factories do not work unless they
          are in the same cluster as the destination.)
          3) This work-around will not work for non-WebLogic JMS topics.