[seam-dev] [seam-persistence] ManagedPersistenceContextExtension

[John D. Ament]

But is the select for update done inside the entitymanager object or a query
instance?  I don't think EntityManager.find(Class,Id) does any type of hold
on the object found.

John

On Sun, Jul 10, 2011 at 7:15 PM, Mark Struberg <struberg at yahoo.de> wrote:

> Stu, whenever you do a "select for update" or any manual locking, you will
> end up with an EntityManager which cannot be transfered to another node.
> Even if hibernate marks it's EntityManager Serializable, it just isn't if I
> didn't miss something!
>
> LieGrue,
> strub
>
> --- On Sun, 7/10/11, Stuart Douglas <stuart.w.douglas at gmail.com> wrote:
>
> > From: Stuart Douglas <stuart.w.douglas at gmail.com>
> > Subject: Re: [seam-dev] [seam-persistence]
> ManagedPersistenceContextExtension
> > To: "Mark Struberg" <struberg at yahoo.de>
> > Cc: seam-dev at lists.jboss.org
> > Date: Sunday, July 10, 2011, 11:07 PM
> >
> > On 11/07/2011, at 4:07 AM, Mark Struberg wrote:
> >
> > > Hi folks!
> > >
> > > While reviewing an OWB bug report, 2 questions came
> > up:
> > >
> > > a.) EnvironmentUtils#isEEEnvironment() relies on the
> > absence of 'javax.ejb.Stateless' to decide if a
> > PersitenceUnit gets injected or if you need to do it
> > yourself. I think this is an unrelieable assumption. E.g.
> > there are a few Extensions which emulate Stateless Session
> > beans via a CDI Extension by morphing them into
> > @ApplicationScoped.
> >
> > This is not ideal, but I don't think there is really any
> > portable way to detect if the environment is an EE
> > environment or not. I was originally planning to add a
> > method for configuring this, but it appears I did not get
> > around to it.
> >
> > >
> > > b.) in
> > ManagedPersistenceContextExtension#registerManagedPersistenceContext
> > you register the bean for the EntityManager as
> > passivationCapable. This is never _never_ NEVER true. The
> > EntityManager is not Serializable! There is imo no way to
> > have an EntityManager in a bean scoped other than
> > @RequestScoped or shorter (e.g. @TransactionalScoped). Any
> > other trick is not working in a portable way. This is mainly
> > caused by JPA still supporting pessimistic locking (_real_
> > locks in the database) as first class citizens.
> > >
> >
> > Without this it is not possible to have a conversation
> > scoped entity manager. The hibernate EntityManager is in
> > fact Serializable. Locks should not be a problem as long as
> > you do not attempt to serialise the EM in the middle of a
> > transaction.
> >
> > Stuart
> >
> >
> > > But I'd be happy if anyone could enlighten me and tell
> > us how it works ;)
> > >
> > > LieGrue,
> > > strub
> > > _______________________________________________
> > > seam-dev mailing list
> > > seam-dev at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/seam-dev
> >
> >
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