[hibernate-dev] HHH-7018 and one more change to how we serialize EntityManagerFactory instances...
steve at hibernate.org
Tue Feb 7 09:08:33 EST 2012
How is actually, physically serializing a EMF *instance* to another VM
a valid use case? Notice that the case of writing the UUID/name to the
serial stream is explicitly different that this. That approach is just
tokenizing the way to resolve the proper reference to the EMF on deser
using that UUID/name.
So what is the actual valid use case for "duplicate
EntityManagerFactory [creation]" on ser/deser? To me, on deser you
resolve the name reference if possible; if not, you resolve the UUID
reference; otherwise, you throw an error. This is exactly what we do
with SessionFactory btw in terms of ser/deser. Why is that not the
On Mon 06 Feb 2012 10:32:01 PM CST, Scott Marlow wrote:
> Feedback is welcome on a proposed change for HHH-7018
> When we serialize the EntityManagerFactory in 4.0.0, there can be
> nonserializeable objects in the EMF configuration properties (e.g.
> JTA_PLATFORM, datasource, other stuff). In most cases, we will have a
> session factory name (preferred) or persistence unit name to uniquely
> identify the EntityManagerFactory. In 4.0.1, during serialization, we
> only serialize the (hopefully) unique name.
> If a duplicate EntityManagerFactory is created (by name), no immediate
> error is given, instead we only give an error later when deserializing
> the EMF. The HibernateException thrown during deserialization will look
> "registry contains more than one (" +
> entityManagerFactorySet.size()+ ") entity manager factories: "
> + name
> If that causes issues for any application, the SESSION_FACTORY_NAME can
> be passed in from the troubled application (possibly with
> SESSION_FACTORY_NAME_IS_JNDI set to false but true is also fine).
> For the 4.1 release, I would like to take this one step further. The
> above changes, only were made for EntityManager serialization of the EM
> to EMF reference. The next step is to apply the same change to the EMF
> readObject/writeObject, such that we also allow the EMF to be serialized
> when it contains nonserializable objects. This also simplifies the EM
> serialization, as it can just use default serialization for the EMF.
> The proposed commit (to be fixed in 4.1) is at
> Feedback on the change is welcome (we are building 4.1 final middle of
> this week).
> hibernate-dev mailing list
> hibernate-dev at lists.jboss.org
steve at hibernate.org
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