Updating something???

Question

Hi,
I am kind of lost with the update functionality in Toplink. any suggestion/experience for a true usage scenario is more than welcome. (by update functionality I mean update/delete/insert throughout the rest of the message as well)
Let me figure out the design structure I have on hand.
Application server (OC4J).
1 stateful session bean to collect requests from users and delegate the requests to Toplink persistence layer.
Java classes, representing db tables and relations. Defined using Toplink Mapping Workbench application, but code generation is done template-driven (outside the scope of mwb) to have customized features. But it has enough information for Toplink to be able to select/update/insert/etc operations.
I use SessionManager, ServerSession, ClientSession concepts to implement persistence layer. For update functionality I see that I must use UnitOfWork, first register objects and then do changes and call commit. but in my design, when the object arrives to the Toplink layer for update, it's assumed that the user has already made required changes (set attributes if it's an insert request) and Toplink is expected to perform this update operation on database within the context of a session-wide transaction which is external to Toplink.
so what would be the best way to make use of Toplink (UnitOfWork basically) to have update functionality implemented.
Regards.

Answer 1

Where are the objects that are being passed for update coming from?
If you are reading them, serializing them to a client, serializing them back, then updating them you can make use of the mergeClone API, or merge the changes yourself.
i.e.
public void updateObject(Object serializedObject) {
UnitOfWork uow = session.acquireUnitOfWork();
uow.mergeClone(serializedObject);
uow.commit();
If you are reading them, changing them directly without serializing them, then updating them, then you must read them through the unit of work, and simply call commit to update them.
For more information refer to the "Merging (1-52)" section in the "Foundation Library Reference Guide".