Request for "AggegrateCollectionMapping" example.

Question

Dear all,
Did you try aggegrateCollectionMapping? Would you mind to share some example for me?
I have modified the example from the developer guide. When I execute the test program, I get the following error message:
ocal Exception Stack:
Exception [TOPLINK-0] (OracleAS TopLink - 10g (9.0.4.4) (Build 040627)): oracle.toplink.exceptions.IntegrityException
Descriptor Exceptions:
Exception [TOPLINK-153] (OracleAS TopLink - 10g (9.0.4.4) (Build 040627)): oracle.toplink.exceptions.DescriptorException
Exception Description: The reference descriptor for [com.oocl.frm.persistence.poc.test.DataValue] should be set to be an Aggregate Collection descriptor.
Mapping: oracle.toplink.mappings.AggregateCollectionMapping[dataValueList]
Descriptor: Descriptor(com.oocl.frm.persistence.poc.test.AggObject1 --> [DatabaseTable(AGGOBJECT1), DatabaseTable(AGGOBJECT1)])
Exception [TOPLINK-93] (OracleAS TopLink - 10g (9.0.4.4) (Build 040627)): oracle.toplink.exceptions.DescriptorException
Exception Description: The table [DATAVALUE] is not present in this descriptor.
Descriptor: Descriptor(com.oocl.frm.persistence.poc.test.AggObject1 --> [DatabaseTable(AGGOBJECT1), DatabaseTable(AGGOBJECT1)])
Exception [TOPLINK-41] (OracleAS TopLink - 10g (9.0.4.4) (Build 040627)): oracle.toplink.exceptions.DescriptorException
Exception Description: A non-read-only mapping must be defined for the sequence number field.
Descriptor: Descriptor(com.oocl.frm.persistence.poc.test.AggObject1 --> [DatabaseTable(AGGOBJECT1), DatabaseTable(AGGOBJECT1)])
Runtime Exceptions:
     at oracle.toplink.publicinterface.DatabaseSession.initializeDescriptors(DatabaseSession.java:425)
     at oracle.toplink.publicinterface.DatabaseSession.initializeDescriptors(DatabaseSession.java:356)
     at oracle.toplink.publicinterface.DatabaseSession.login(DatabaseSession.java:532)
     at oracle.toplink.tools.sessionmanagement.SessionManager.getSession(SessionManager.java:250)
     at oracle.toplink.tools.sessionmanagement.SessionManager.getSession(SessionManager.java:192)
     at oracle.toplink.tools.sessionmanagement.SessionManager.getSession(SessionManager.java:149)
     at com.oocl.frm.persistence.poc.pal.TopLinkSessionManager.login(TopLinkSessionManager.java:24)
     at com.oocl.frm.persistence.poc.pal.TopLinkSessionManager.getServerSession(TopLinkSessionManager.java:44)
     at com.oocl.frm.persistence.poc.pal.BasicAccessServiceProvider.addOrUpdateObject(BasicAccessServiceProvider.java:242)
     at com.oocl.frm.persistence.poc.test.PersistentArrayListTester.objCreation(PersistentArrayListTester.java:137)
     at com.oocl.frm.persistence.poc.test.PersistentArrayListTester.main(PersistentArrayListTester.java:23)
Do you have idea of them?
Thanks and regards,
William

Answer 1

Hi William,
I managed to get it to work with TopLink 10g Developer Preview 3.
There are two objects in my example, VoCsm - header, VoCsmLine - child, (similar to Invoice - Invoice Line).
First step is to create a mapping in Mapping workbench as if it would be normal 1:n relation, don't forget to specify all needed infos, like foreign key fields and so on.
Second step is to create one additional class as follows:
public class RelationsAdjuster {
     public static void adjustVoCsmLine(oracle.toplink.descriptors.ClassDescriptor pDescriptor) {
     pDescriptor.descriptorIsAggregateCollection();
     public static void adjustVoCsm(oracle.toplink.descriptors.ClassDescriptor pDescriptor) {
          OneToManyMapping vCsmLineListMapping = (OneToManyMapping) pDescriptor.getMappingForAttributeName("mCsmLineList");
          AggregateCollectionMapping vNewMapping = new AggregateCollectionMapping();
          vNewMapping.setAttributeName(vCsmLineListMapping.getAttributeName());
          vNewMapping.setUsesIndirection(vCsmLineListMapping.usesIndirection());
          vNewMapping.privateOwnedRelationship();
          vNewMapping.setSourceKeyFields(vCsmLineListMapping.getSourceKeyFields());
          vNewMapping.setTargetForeignKeyFields(vCsmLineListMapping.getTargetForeignKeyFields());                         
          vNewMapping.setReferenceClass(vCsmLineListMapping.getReferenceClass());
          pDescriptor.getMappings().remove(vCsmLineListMapping);
          pDescriptor.addMapping(vNewMapping);
Sorry for missing comments in the above code, You will have to go through it line by line and check API description for corresponding methods.
Third is to go back to Mapping Workbench and click "Select Advanced Properties" with the right mouse botton on each of these two objects. Then select "After Load" check-box and You will see one additional tab "After Load" appearing in these two mapping descriptors.
Finally go to that new tab, select the above RelationsAdjuster class and the corresponding static method. There is one more pitfall there, it's not enough to have this additional class on the classpath, You have to add it to Your mapping as if it would be a class, You want to persist, than You will be able to select the corresponding static methods from the drop-down list. After that You can remove RelationsAdjuster class from Your mapping. Hopefully this is just because of "Developer Preview".
Please note, this is just an example, it works, but this is not a production code,we don't use TopLink in production environment.
So, have fun, don't hesitate to ask me if You have some further questions.
Regards
Oleg