Use of javax.jdo.Transaction in BMT

Question

Sections 16.1.3 and 16.1.4 of the JDO spec (version 0.95) state that the
application code with a Bean Managed Transaction has the option of
getting a Persistence Manager before a UserTransaction is opened and
managing the transaction through the javax.jdo.Transaction interface.
When I attempt this in Kodo 2.1.2 (EE), I get the following exception
thrown:
javax.jdo.JDOUserException: The global UserTransaction must be used for
begin/commit/rollback.
at
com.techtrader.modules.jdo.ee.EEPersistenceManager.begin(EEPersistenceManager.java:62)
at
com.ysoft.jdo.book.restaurant.MenuManagerImpl.getObjectsByQuery(MenuManagerImpl.java:108)
Is this the expected behavior for Kodo? If so, it appears to be a bug.
If not, then perhaps I am doing something wrong.
David Ezzio
Yankee Software

Answer 1

You're right, we don't implement that feature of the spec yet. And
unfortunately, if we do implement it, we'll break another part of the
spec in doing so. Let me explain:
In enterprise situations, there are two requirements for transaction
management:
* In container-managed EJBs, the javax.jdo.Transaction interface cannot
be used and must throw an exception on begin/commit/rollback.
* In bean-managed EJBs, the javax.jdo.Transaction interface should tie
into the gobal UserTransaction and can be used for begin/commit/rollback.
Now, the problem is, there is absolutely no way for a generic JDO
implementation without appserver-specific hooks to know whether it is
being executed from a container managed or bean managed EJB. None. So
if we allow control of the UserTransaction through the
javax.jdo.Transaction, we'd have to allow all the time, including for
container managed beans.
The good news is that most EJB containers will detect our messing with
the transaction state manually in a container-managed EJB and throw the
proper Exception themselves, so we could probably get away with this.
And in fact this is exactly what we plan to do -- go ahead and always
allow transaction management through the javax.jdo.Transaction interface
and hope containers detect errors themselves.
Well, I'm sure that was much more information than you needed :)
Anyway, expect to see this feature implemented in the next version of
the Enterprise Edition, due out next month.
-- Abe White
Kodo Product Team
David Ezzio wrote:
Sections 16.1.3 and 16.1.4 of the JDO spec (version 0.95) state that the
application code with a Bean Managed Transaction has the option of
getting a Persistence Manager before a UserTransaction is opened and
managing the transaction through the javax.jdo.Transaction interface.
When I attempt this in Kodo 2.1.2 (EE), I get the following exception
thrown:
javax.jdo.JDOUserException: The global UserTransaction must be used for
begin/commit/rollback.
at
com.techtrader.modules.jdo.ee.EEPersistenceManager.begin(EEPersistenceManager.java:62)
at
com.ysoft.jdo.book.restaurant.MenuManagerImpl.getObjectsByQuery(MenuManagerImpl.java:108)
Is this the expected behavior for Kodo? If so, it appears to be a bug.
If not, then perhaps I am doing something wrong.
David Ezzio
Yankee Software