Hi!
The implementation of this is in EntitySynchronizationInterceptor.java.
Lennart Petersson wrote:
> Reading the EJB 1.1 spec about exception handling and can't really
> figure out what happens in a situation like this one:
>
> If an EntityBean (CMP) has changed some of its persistent fields but
> then decides to throw an appl. exception (that is before any update in
> db has been made), what happens with the changed fields in the bean
> instance?
>
> Case 1: The tx is started in the EntityBean method and the method calls
> on setRollbackOnly() before throwing the exception. I guess that the
> container rollbacks the ongoing tx and rethrows the exception. The bean
> instance in intact and can be used again. What about the fields?
The instance will be sent back to the pool, i.e. next usage of entity
will cause activation/load.
> Case 2: Same as 1 but there is no call on setRollbackOnly(). Here i
> guess that the container will attempt to commit the tx, the changed
> fields will be stored in db, and then rethrows the exception. The bean
> instance is intact and will have 'correct' field values. At least they
> are the same as in db.
Correct.
> Case 3: The tx is already started by the caller and the caller retries
> the call within the same tx. Here i guess that the container will
> rethrow the exception to the caller. The bean instance is intact. The
> caller calls the method again - but what value have the field then?
The values they had when your instance threw the initial exception. The
container will not do anything.
> Case 4: Like 3 but the caller calls setRollbackOnly() and rethrows the
> exception. Here i guess that the container will rollback the tx.
Yes.
> The
> bean instance is intact. But what about the field values?
They are considered stale and will be reloaded on next call.
> Case 5: Like 3 but the caller just rethrows the exception without
> calling setRollbackOnly(). Here i guess that the container will attempt
> to commit the tx, the changed fields will be stored in db, and then
> rethrows the exception. The bean instance is intact and will have
> 'correct' field values like in case 2.
Yes.
> My problem: I'm really worried about what values the entity fields will
> have, especially in the cases where the tx has been rolled back and no
> update done in database! Do i have to manually reset the fields to its
> originally value before throwing the appl. exception?
As above, the instance will be sent back to the pool, and thus
activated/*reloaded* on next usage.
> Any comments to this rather basic EJB question? Maybe i'm stupid but for
> the moment when i reads the spec i think that everything is a bit messy.
Is it clearer now?
/Rickard
--
Rickard �berg
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