[hibernate-dev] hibernate-osgi JPA bootstrap & classloader

[Steve Ebersole]

I created the following 2 issues to track these improvements:

https://hibernate.atlassian.net/browse/HHH-9818
https://hibernate.atlassian.net/browse/HHH-9819



On Tue, May 26, 2015 at 3:57 PM, Steve Ebersole <steve at hibernate.org> wrote:

> Awesome, thanks!  So I'll investigate BundleListener...
>
> Is that the best way to know when TransactionManagers and DataSources come
> and go too?  Or is there a more specific concept for listening to an "OSGi
> service"?
>
> Also, do the containers generally handle "in-flight" requests in regards
> to TransactionManagers and DataSources on activated/deactivated?  I guess
> this is more a curiosity, since I do not see what we could do if the
> container does not manage it.
>
> On Tue, May 26, 2015 at 3:26 PM, Brett Meyer <brmeyer at redhat.com> wrote:
>
>> > I would fully expect hibernate-osgi to not directly use Bootstrap to
>> build
>> > an EntityManagerFactoryBuilder.  Bootstrap is geared toward users
>> wanting
>> > to leverage 2-phase JPA bootstrapping, not our components.  I would have
>> > expected Enterprise OSGi support to instead directly build (and possibly
>> > override) EntityManagerFactoryBuilderImpl.  I'll add that as a task for
>> > post-5.0.
>>
>> +1, makes sense.  I should have done that to begin with...
>>
>> > Because I think that is a first step in being able to better
>> > manage bundles coming and going.  Please correct me if I am wrong.
>>
>> At first glance, supporting bundles being activated/deactivated at
>> runtime may just be limited to OsgiClassLoader and an impl of OSGi's
>> "BundleListener".  HibernateBundleActivator would simply register that
>> listener during startup (BundleContext#addBundleListener), which would
>> receive the events.  As bundles are added/removed from the runtime, they'd
>> just be added/removed from OsgiClassLoader#bundles.
>>
>> > Also I'd like to start making sure that we fully support (certain) OSGi
>> services
>> > being replaced.  Especially thinking of TransactionManagers and
>> DataSources.
>>
>> +1
>>
>> >
>> >
>> > On Tue, May 26, 2015 at 10:44 AM, Brett Meyer <brmeyer at redhat.com>
>> wrote:
>> >
>> > > IIRC:
>> > >
>> > > OsgiPersistenceProvider and OsgiSessionFactoryService both need
>> *some* way
>> > > to build the OsgiClassLoader and pass it into Hibernate
>> bootstrapping.  For
>> > > the SF, that's easy: just hand OSGiClassLoaderServiceImpl to
>> > > BootstrapServiceRegistryBuilder.  For EMF, it looks like I mistakenly
>> > > overrode those Bootstrap methods -- I missed that
>> PersistenceUnitDescriptor
>> > > included the CL.  So you're probably right -- presumably you could
>> strip
>> > > 'em out and somehow use the descriptor, but you might still need the
>> > > overridden method in HibernatePersistenceProvider so that
>> > > OsgiPersistenceProvider can give you the OsgiClassLoader to use.
>> > >
>> > > > Additionally, this ClassLoader is ultimately just used to build the
>> > > > ClassLoaderService which hibernate-osgi overrides anyway.
>> > >
>> > > Right, assuming you're talking about
>> > > 'ClassLoaderHelper.overridenClassLoader'.  But the intention there
>> was to
>> > > remove that whole class ASAP -- that was just a temporary hack for
>> ORM 4,
>> > > since CL handling was still really static.  But admittedly, I'm a bit
>> out
>> > > of touch with ORM 5, so I'm not sure if that's feasible yet.
>> > >
>> > > ----- Original Message -----
>> > > > From: "Steve Ebersole" <steve at hibernate.org>
>> > > > To: "hibernate-dev" <hibernate-dev at lists.jboss.org>
>> > > > Sent: Saturday, May 23, 2015 1:49:50 PM
>> > > > Subject: [hibernate-dev] hibernate-osgi JPA bootstrap & classloader
>> > > >
>> > > > Brett,
>> > > >
>> > > > As part of HHH-7527 (Enterprise OSGi support) you had changed
>> > > > the org.hibernate.jpa.boot.spi.Bootstrap contract to basically
>> overload
>> > > > each method to additional accept a "providedClassLoader".
>> > > >
>> > > > Every one of those methods however, also accepts
>> > > > a org.hibernate.jpa.boot.spi.PersistenceUnitDescriptor which
>> exposes 2
>> > > > ClassLoader already.
>> > > >
>> > > > Additionally, this ClassLoader is ultimately just used to build the
>> > > > ClassLoaderService which hibernate-osgi overrides anyway.
>> > > >
>> > > > Just curious if I missed something.  Unless I did, it seems to me
>> that we
>> > > > really do not need these overloads on Bootstrap to support
>> Enterprise
>> > > > OSGi.  This dove-tails with a discussion from the Karaf user list
>> > > > ultimately discussing OsgiClassLoaderService and "holding bundles"
>> that
>> > > are
>> > > > being re-installed or upgraded.  Ultimately I am thinking through
>> ways to
>> > > > support being able to release OSGI bundle references from the
>> > > > OsgiClassLoaderService...
>> > > > _______________________________________________
>> > > > hibernate-dev mailing list
>> > > > hibernate-dev at lists.jboss.org
>> > > > https://lists.jboss.org/mailman/listinfo/hibernate-dev
>> > > >
>> > >
>> >
>>
>
>