Thanks for pointing this out. Fixed, see https://issues.apache.org/ jira/browse/GERONIMO-2795.

When first reading the javadoc I was being a bit too picky and decided that "register a synchronization" meant you could only register one despite not being able to see how this would work if you had more than one jpa provider used in a tx. I see this is the same wording that tx.registerSynchronization uses so presumably the intent ought to be clear :-)

BTW I continue to be unable to find any jta 1.1 documentation other than the javadoc. Has anyone else found an actual spec? I've been looking at http://java.sun.com/products/jta/

thanks
david jencks

On Feb 4, 2007, at 12:11 PM, Craig L Russell wrote:

Hi Andrus,

On Feb 4, 2007, at 8:37 AM, Andrus Adamchik wrote:

Hi Dain,

Just got some time to write a JPA/OpenEJB integration test following your example. Everything works except for one thing. Here is my sample code:

GeronimoTransactionManagerJTA11 tm = new GeronimoTransactionManagerJTA11();
        System.setProperty(
                Context.INITIAL_CONTEXT_FACTORY,
                LocalInitialContextFactory.class.getName());

new InitialContext().bind("java:comp/ TransactionSynchronizationRegistry", tm);

EntityManagerFactory factory = ... // init code for Cayenne JTA EMF JtaEntityManagerRegistry registry = new JtaEntityManagerRegistry(tm);

        tm.begin();

        EntityManager entityManager = new JtaEntityManager(
                registry,
                factory,
                new Properties(),
                false);


        SimpleEntity e = new SimpleEntity();
        e.setProperty1("XXX");
        entityManager.persist(e);
        tm.commit(); // Nothing is saved to the DB here

Now the problem...

According to the JPA spec, ch. 5.9.2, "When EntityManagerFactory.createEntityManager is invoked, the provider must create and return a new entity manager. If a JTA transaction is active, the provider must register for synchronization notifications against the JTA transaction."

So that's what Cayenne EMF does [1], [2] via TransactionSynchronizationRegistry.registerInterposedSynchronization( ..). At a later time OpenEJB JtaEntityManager calls the same method on the registry to register a its own close operation, kicking out Cayenne EM callback. The end result is that the EntityManager is not flushed in "beforeCompletion" and nothing is saved to DB.

I suspect Geronimo TransactionImpl is to blame here. It only allows a single interposed synchronization. Is it a requirement of the JTA spec?

The intent of the registerInterposedSynchronization method is to allow any number of callbacks to be registered for synchronization.

It's a bug if only one is allowed. There is no requirement for any particular ordering among the callbacks but multiple callbacks are required to be supported.

Craig

(if it is, I couldn't find any mention of it). If everyone agrees with my assessment of the situation, I can submit a patch.

Thoughts?

Andrus


[1] https://svn.apache.org/repos/asf/cayenne/main/trunk/framework/ cayenne-jpa-unpublished/src/main/java/org/apache/cayenne/jpa/ JtaEntityManagerFactory.java [2] https://svn.apache.org/repos/asf/cayenne/main/trunk/framework/ cayenne-jpa-unpublished/src/main/java/org/apache/cayenne/jpa/ JtaEntityManager.java


On Jan 11, 2007, at 10:34 PM, Dain Sundstrom wrote:

I just committed the JtaEntityManager and JtaEntityManagerRegistry to the openejb-persistence module. You can create a JtaEntityManager with the following code:

JtaEntityManagerRegistry registry = new JtaEntityManagerRegistry (transactionSynchronizationRegistry);
EntityManager entityManager = new JtaEntityManager(registry,
        entityManagerFactory,
        properties,
        extended);

That's it. The under the covers of the JtaEntityManager a new EntityManager instance is created using the EMF for each transaction.

A single instance of the JtaEntityManagerRegistry should be shared by all JtaEntityManagers. TransactionSynchronization registry is a new interface in JTA 1.1. The Geronimo JTA 1.1 transaction manager implements this interface directly, but if you are not using that transaction manager just wrap your transaction manager with the openejb SimpleTransactionSynchronizationRegistry.

If you want to test extended entity managers (only used by stateful session beans), you will need to simulate stateful session bean construction, entrance, exit and starting of user transactions by call in the appropriate method on the JtaEntityManagerRegistry.

If you run into problems, don't hesitate to ask.

-dain



Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!


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