Hi, you are right about the samples, it is on my todo list, but I haven't got to it yet.
I've written some documentation as a result of your email. It isn't on our website yet, it needs to sync from the wiki, but you can view it here: https://cwiki.apache.org/confluence/display/ARIES/JNDIProject Alasdair On 17 September 2010 07:45, Bengt Rodehav <[email protected]> wrote: > Thanks for the clarification Alasdair, > Are there any samples/examples of "osgi:" I can look at. Do I need to add a > namespace in the persistent descriptor, deploy certain bundles etc? > Clearly, the way you describe it, "osgi:" must be preferred to "aries:". > Maybe the Aries samples should change to reflect that? > /Bengt > > 2010/9/17 Alasdair Nottingham <[email protected]> >> >> aries:services is also a JNDI lookup scheme, it works much the same way as >> osgi:service, but osgi:service returns a proxy to the target object which >> switches out the target if it changes. aries:services does not proxy, you >> get e raw object so it is a little bit less dynamic and safe. >> >> Alasdair Nottingham >> On 17 Sep 2010, at 03:10, Bengt Rodehav <[email protected]> wrote: >> >> Have I misunderstood when I use "aries:" instead of "osgi:" or is it just >> different prefixes to the same namespace? In the JPA samples I cannot see in >> the persistence descriptor what namespace "aries:" actually refers to. >> /Bengt >> >> 2010/9/17 Timothy Ward <[email protected]> >>> >>> Hi Harald, >>> >>> The Aries project aims to provide a managed programming model, and as >>> such the Aries JPA runtime is not an implementation of the JPA service >>> specification. >>> >>> As a result I'm afraid my first answer is no, Aries JPA cannot be used to >>> get unmanaged JPA support, however if you declare your persistence units to >>> use RESOURCE_LOCAL transactions then there shouldn't be a need for OpenJPA >>> to load any JTA classes. Please let me know if OpenJPA continues to complain >>> about the lack of JTA interfaces for RESOURCE_LOCAL persistence units and >>> I'll try to get that fixed. >>> >>> For your requirements you should need two bundles from the Aries JPA >>> project, the Aries JPA API bundle and the Aries JPA container bundle. You >>> will also need the Aries Util bundle, which the JPA project uses. >>> >>> For reference, the JPA container bundles provide the following support: >>> >>> jpa-api :- Core interfaces used by the Aries JPA runtime >>> and Service providers >>> jpa-container :- The core JPA container, provides managed >>> EntityManager factories for use in Application-Managed JPA >>> jpa-container-context :- JPA managed persistence context support, allows >>> for bundles to be registered as clients of a managed persistence context >>> jpa-blueprint-aries :- Integration with the aries blueprint service >>> providing a custom namespace for JPA resource injection >>> >>> >>> The Aries JPA container is loosely coupled, so it is entirely possible to >>> pick the bundles you need for the support you want, though each piece of >>> support builds upon the previous one, so it doesn't make much sense to have >>> managed persistence context support without managed persistence unit >>> support. >>> >>> There's no need to use blueprint, Declarative Services is perfectly >>> capable of retrieving EntityManagerFactory services from the service >>> registry. >>> >>> How data sources are discovered depends upon how they are configured, if >>> you use the <jta-data-source> or <non-jta-data-source> tag, then the Aries >>> JPA container will use JNDI to get the resource registered with that JNDI >>> name. In most cases you actually want to access a DataSource object in the >>> service registry, which means you need the Aries JNDI support (available as >>> a single bundle, or as separate core and URL handler bundles) which provides >>> the osgi: namespace. >>> >>> If you want to specify database driver class names in the <properties> >>> section of the persistence unit then the JPA provider needs to be able to >>> load those drivers. I do not know whether OpenJPA has support for the OSGi >>> JDBC service specification, or whether they will simply try to load the >>> driver classes, and so this may not work. >>> >>> I hope this message has been helpful, and I agree that there is >>> insufficient documentation in this area. I would be more than happy for any >>> Aries users to contribute information that they find useful so that better >>> documentation can be built. >>> >>> Regards, >>> >>> Tim >>> >>> ---------------------------------------- >>> > From: [email protected] >>> > To: [email protected] >>> > Date: Thu, 16 Sep 2010 20:31:48 +0200 >>> > Subject: OSGi JPA and JDBC Services >>> > >>> > I'm currently trying to make OpenJPA 2.0.1 work in an OSGi environment, >>> > and while looking for examples, I found a pointer to Apache Aries on the >>> > OpenJPA Users' mailing list. >>> > >>> > So I had a look at the Aries website, checked out the latest code from >>> > trunk, played around with it for a couple of hours and was left with no >>> > usable result - it sort of feels like being offered a four course meal >>> > when >>> > all you were asking for was a plate of soup, and you don't even get a >>> > spoon... >>> > >>> > All I want to do is use OpenJPA in plain old unmanaged mode and have it >>> > discover my persistence units and load classes from my application bundles >>> > without DynamicImport-Package, buddy policies or fragments. I am currently >>> > perfectly happy with Declarative Services and have no intention of >>> > converting my application to Blueprint. >>> > >>> > Can Aries be used to achieve just that? If so, what is the minimum set >>> > of Aries bundles I need to include in my application? >>> > >>> > I got as far as having my persistence unit discovered, but on creating >>> > an EntityManagerFactory, OpenJPA always complained about missing JTA >>> > support. Does Aries implement unmanaged JPA at all? (It is supported by >>> > the >>> > OSGi JPA spec, at any rate.) I can only see a call of >>> > PersistenceProvider.createContainerEntityManagerFactory() in Aries and no >>> > occurrence of createEntityManagerFactory(). On the OpenJPA side, there is >>> > some code related to OSGi classloaders, but again, this is just used for >>> > the >>> > managed factories and not for the unmanaged ones. >>> > >>> > Another question: how does the Persistence Provider discover the data >>> > source - where does the magic happen so that the lookup of >>> > osgi:service:/javax.sql.DataSource will work? Is that done by Aries alone, >>> > or does the persistence provider need to be OSGi aware in this respect? >>> > >>> > Thanks in advance for any hints! >>> > >>> > Best regards, >>> > Harald >>> > > -- Alasdair Nottingham [email protected]
