[seam-dev] Seam/jBPM integration within the SOA platform

[Kevin Conner]

Dan Allen wrote:
> Of course, then you must have Seam doing all calls to jBPM or else you
> will be outside of a transaction. I'm unaware of whether this was
> considered (not saying it wasn't). That explains, though, why Seam has
> the workInTransaction callbacks.

This is the configuration we are using

    <service name="persistence">
      <factory>
        <bean
class="org.jbpm.persistence.jta.JtaDbPersistenceServiceFactory">
          <field name="isTransactionEnabled"><false/></field>
          <field name="isCurrentSessionEnabled"><true/></field>
        </bean>
     </factory>
     </service>

This is similar to the seam configuration except that the
JtaDbPersistenceServiceFactory will create a JTA transaction if one does
not already exist.

The specific issue we are seeing relates more to the hibernate behaviour
rather than explicit jBPM behaviour.  The configuration in SOA is such
that we end up using a JTASessionContext within hibernate and this is
configured to close the session when the transaction terminates.  Any
subsequent transaction usage on the same session, or even manipulation
of the objects outside of the transaction, will result in the following.

>     When running a seam example on the SOA platform we were seeing an
>     exception being thrown as a result of a hibernate session being used
>     after it has previously been closed, this was a SessionException with
>     the text "Session is closed!".

The seam integration can reuse the same jBPM context in different
transactions and also pass the hibernate objects outside of the
transaction.  Both of these scenarios result in unusable context and/or
hibernate objects within the SOA environment.

	Kev

BTW The two instances of passing objects outside of the transaction
boundary were found in ProcessInstance and TaskInstance.  Wrapping the
invocation from Contexts created a transaction that also encompassed the
method invocations on those objects.

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