4 Replies Latest reply on Nov 10, 2003 3:04 PM by ergomy

    How to convert CMR Proxy to EJBLocalObject?

    ergomy Newbie


      I've implemented a Many to Many CMR. When I call either accessor the collection get's loaded with JBoss Proxies.

      When iterating through the collection and attempting to cast an individual proxy to the correct EJBLocalObject it fails with a ClassCast Exception.

      Couldn't find an example in the CMP manual or 3.2 Admin Manual.

      Can anyone point me in the right direction so that I can use these EJBs?

      Thanks!

        • 1. Re: How to convert CMR Proxy to EJBLocalObject?
          Raja Master

          Can you post some code or the exception ? This should be pretty standard behaviour so it shud work ;-)

          -Raj

          • 2. Re: How to convert CMR Proxy to EJBLocalObject?
            ergomy Newbie

            Thanks for your reply.. Yes, i expected that it would be straightforward and haven't had a problem implementing CMR with 1 to Many relationships. So I'm baffled and certain i've missed something simple.

            But your help will be greatly appreciated.

            Here is the code and exception...

            EJB-JAR.XML

            <ejb-relation>
            <ejb-relation-name>usergroup-user</ejb-relation-name>
            <ejb-relationship-role>
            <ejb-relationship-role-name>usergroups-have-users</ejb-relationship-role-name>
            Many
            <relationship-role-source>
            <ejb-name>TheUserGroup</ejb-name>
            </relationship-role-source>
            <cmr-field>
            <cmr-field-name>members</cmr-field-name>
            <cmr-field-type>java.util.Collection</cmr-field-type>
            </cmr-field>
            </ejb-relationship-role>
            <ejb-relationship-role>
            <ejb-relationship-role-name>users-have-usergroups</ejb-relationship-role-name>
            Many
            <relationship-role-source>
            <ejb-name>TheUser</ejb-name>
            </relationship-role-source>
            <cmr-field>
            <cmr-field-name>userGroups</cmr-field-name>
            <cmr-field-type>java.util.Collection</cmr-field-type>
            </cmr-field>
            </ejb-relationship-role>
            </ejb-relation>

            jbosscmp-jdbc.xml

            <ejb-relation>
            <ejb-relation-name>usergroup-user</ejb-relation-name>
            <relation-table-mapping>
            <table-name>user_usergroups</table-name>
            </relation-table-mapping>
            <ejb-relationship-role>
            <ejb-relationship-role-name>usergroups-have-users</ejb-relationship-role-name>
            <key-fields>
            <key-field>
            <field-name>groupId</field-name>
            <column-name>usergroup_id</column-name>
            </key-field>
            </key-fields>
            </ejb-relationship-role>
            <ejb-relationship-role>
            <ejb-relationship-role-name>users-have-usergroups</ejb-relationship-role-name>
            <key-fields>
            <key-field>
            <field-name>userId</field-name>
            <column-name>user_id</column-name>
            </key-field>
            </key-fields>
            </ejb-relationship-role>
            </ejb-relation>

            Snippet of Java inside "TheUserGroup" entity bean that is called after the bean has been loaded by finder

            Iterator users = getUsers().iterator();

            while( users.hasNext() ){

            UserEntityLocal userLocal = (UserEntityLocal)users.next();
            Globals.getTrace().traceInfo( "user - name " + userLocal.getName());

            }

            Exception that occurs when attempting to access userLocal..

            java.sql.SQLException: Unable to load to deserialize result: java.io.InvalidClassException: com.transensory.ergomy.model.MemberImpl; local class incompatible: stream classdesc serialVersionUID = 8309846566778834449, local class serialVersionUID = -2781449848339997329
            at org.jboss.ejb.plugins.cmp.jdbc.JDBCUtil.convertToObject(JDBCUtil.java:747)
            at org.jboss.ejb.plugins.cmp.jdbc.JDBCUtil.getResult(JDBCUtil.java:372)
            at org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCAbstractCMPFieldBridge.loadArgumentResults(JDBCAbstractCMPFieldBridge.java:369)
            at org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCAbstractCMPFieldBridge.loadInstanceResults(JDBCAbstractCMPFieldBridge.java:322)
            at org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadEntityCommand.execute(JDBCLoadEntityCommand.java:190)
            at org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadEntityCommand.execute(JDBCLoadEntityCommand.java:83)
            at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.loadEntity(JDBCStoreManager.java:632)
            at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.loadEntity(JDBCStoreManager.java:614)
            at org.jboss.ejb.plugins.CMPPersistenceManager.loadEntity(CMPPersistenceManager.java:386)
            at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.loadEntity(CachedConnectionInterceptor.java:353)
            at org.jboss.ejb.plugins.EntitySynchronizationInterceptor.invoke(EntitySynchronizationInterceptor.java:232)
            at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:186)
            at org.jboss.ejb.plugins.EntityReentranceInterceptor.invoke(EntityReentranceInterceptor.java:82)
            at org.jboss.ejb.plugins.EntityInstanceInterceptor.invoke(EntityInstanceInterceptor.java:174)
            at org.jboss.ejb.plugins.EntityLockInterceptor.invoke(EntityLockInterceptor.java:89)
            ....



            Thanks again!

            • 3. Re: How to convert CMR Proxy to EJBLocalObject?
              ergomy Newbie



              OOPS.. i realized that I typed in the wrong accessor call in the java snippet i posted. The "cmr-field-name" defined in the ejb-jar.xml is "members" as given in my post. My previous post had a typo in the java snippet section.. i don't call getUsers() but do call the correct accessor.. getMembers().

              Thanks,
              Ed

              • 4. Re: How to convert CMR Proxy to EJBLocalObject?
                ergomy Newbie


                SOLUTION:

                Wouldn't you know it, that shortly after posting the code I figured out the problem. The problem turned out to be unrelated to CMR altogether. It was a Class type mismatch of a blob in the User table and a field in the User Entity bean.

                Sorry if I caused you to scratch your heads.. but hopefully it might help someone else who might be mislead by the same symptoms.

                -Ed