Don't really have the context indeed, I haven't been looking into the
Model-Driven and had no clue where this is happening. I just think this is
more correct than doing everything within the tx demarcation. And indeed
many people don't know about the tx.begin - commit in a row thing. I also
keeps entities managed and hence still enable you to navigate association
lazily... whether or not state got flushed to the database or not. Just
wanted to share with you guys.Still my $.02, make them $.03 in the meantime
;)
On Thu, May 1, 2008 at 1:18 PM, Adam Hardy <[EMAIL PROTECTED]>
wrote:
> Alexander Snaps on 01/05/08 12:02, wrote:
>
> Entity myEntity = em.find(Entity.class, someId);
> >
> > oldValue = myEntity.getSomeField(); // this is only for further down in
> > the
> > mail ;)
> > myEntity.setSomeField(someValue);
> >
> > if(!hasError) {
> > EntityTransaction tx = em.getTransaction();
> > tx.begin();
> > tx.commit(); // Flushes state to DB
> > } else {
> > // do whatever _outside_ of any transaction, like re-ask user to
> > re-enter
> > data
> > }
> >
> > >
> > > Indeed calling the clear operation on the entity manager also results
> > > in
> > >
> > > > all managed entities becoming detached. Beyond many operations on
> > > > the current persistence context might result in the entity manager
> > > > flushing
> > > > state to the database. Yet having it behave differently because of
> > > > updating managed entities outside of the tx also sometimes have the
> > > > persistence context not behave as one would expect...
> > > >
> > > > I'm afraid I can't quite follow you there. (Use of 'beyond'?) The
> > > clear
> > > operation is exactly what I want to do - with the result you mention.
> > > This
> > > is the start of a request (HTTP param conversion and calling setters
> > > on
> > > model properties), with a new EntityManager, so anything that goes
> > > wrong
> > > should cause everything to be cleared.
> > >
> > >
> > > An example of what I mean is if now you'd query for every Entity with
> > someField == oldValue (see above), you'd still get the same instance as
> > myEntity, which would have myEntity.getSomeField().equals(oldValue) ==
> > false!
> >
>
> Yes true but you're not really making use of the struts interceptor
> framework here, which should keep from doing things like that.
>
>
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--
Alexander Snaps <[EMAIL PROTECTED]>
http://www.jroller.com/page/greenhorn
http://www.linkedin.com/in/alexandersnaps
