Jim, Pls see my comments below.
Ta Meeraj >> -----Original Message----- >> From: Jim Marino [mailto:[EMAIL PROTECTED] >> Sent: 03 October 2006 09:00 >> To: [email protected] >> Subject: Re: EJB3 (JPA) support >> >> Hi Meeraj, >> >> I checked in some minor changes to the JPA extension. I was >> thinking things would work along the following lines: >> >> - An application developer could specify a JPA persistence >> context in their assembly using an <import.jpa name="">. Does the name attribute specifies the name of the persistence unit? >> >> - JPAImportLoader would process <import.jpa> and resolve JPA >> artifacts (persistence.xml, mapping files, etc.). It may >> need the composite classloader to do this or come up with a >> better mechanism (I'm too tired to really think about it >> now). JPAImportLoader would >> also create an model of a JPA system service which would be >> used by >> constructed by JPAComponentBuilder to create a JPAAtomicComponent. >> The builder would register this system service in the parent >> (application composite) tree. >> >> - There would be an EntityManagerProcessor registered in the >> *runtime* (as opposed to the application) system tree. When >> a user component marked with @PersistenceContext is >> encountered, EntityManagerProcessor would create a property >> and populate the component type. the property would have a >> EntityManagerObjectFactory which is responsible for >> injecting entity managers on the implementation instance. >> EntityManagerProcessor would call >> resolveSystemInstance() on the parent application composite >> and get the EMF, passing it to an >> EntityManagerObjectFactory. The latter would then be set as >> the default object factory on the property. This is quite similar to how Spring does this. In Spring you can have any managed bean with instance variables of type EntityManagerFactory with the annotation @PersistenceUnit(unitName = "accountModule"). The annotation processor will scan all the persistence XML files for the specified persistence unit name and inject an entity mnager factory that will create the required entity manager. >> >> - When the user component is instantiated, the >> EntityManagerObjectFactory will call to the EMF and create >> an EntityManager. >> >> I started skeleton work to support this but most of the hard >> stuff is missing. For example, I believe we are going to >> need to figure out dependency classloading as both the >> runtime system EntityManagerProcessor and application >> components need access to JPA classes. I probably haven't >> explained this very well, but maybe you could take a look at >> the skeletal code and we could go from there? I have done an svn up and building, I should be able to come back to you by tonight (hopefully :-)) >> >> I definitely think we should draw inspiration from what >> Spring did in terms of integration. For example, we will >> probably need to figure out how to support persistence >> contexts that span more than a transaction. Once we get a >> basic working extension, we may want to look at plugging >> this into a transaction manager, which we'll need for policy support. We can specify the transaction mode (for eg, resource local or JTA) within the persistence XML. JTA would assume a transaction manager is available for lookup (jta-datasource-name property). However, lot of these things should be the concerns of the JPA implementation. >> >> Jim >> >> >> On Oct 2, 2006, at 11:51 PM, Meeraj Kunnumpurath wrote: >> >> > I will take a look Jim and try to assist, I have been doing a bit >> > recently at work with Hibernate JPA and the Spring 2.0 JPA support. >> > May >> > be we can draw some inspiration from Spring 2.0 as well. >> > >> > Ta >> > >> > -----Original Message----- >> > From: Jim Marino [mailto:[EMAIL PROTECTED] >> > Sent: 03 October 2006 07:46 >> > To: [email protected] >> > Subject: Re: EJB3 (JPA) support >> > >> > Yep. I'm working on some minor things to the JPA extension >> now and I >> > should have them checked in soon (hour or so). I'm still >> figuring out >> > how this stuff is going to work (I'm more familiar with >> the Hibernate >> > API than JPA) but perhaps when I do the check in I can >> send another >> > note describing the changes and you can have a look to see >> if it makes >> > sense, and maybe take it forward a bit? I think the >> Hibernate API one >> > should work similarly. >> > >> > Jim >> > >> > On Oct 2, 2006, at 11:36 PM, Meeraj Kunnumpurath wrote: >> > >> >> Do you mean the Hibernate session API without using the entity >> >> manager? >> >> >> >> -----Original Message----- >> >> From: Jim Marino [mailto:[EMAIL PROTECTED] >> >> Sent: 02 October 2006 20:30 >> >> To: [email protected] >> >> Subject: Re: EJB3 (JPA) support >> >> >> >> >> >> On Oct 2, 2006, at 11:35 AM, Meeraj Kunnumpurath wrote: >> >> >> >>> Jim, >> >>> >> >>> From your reply, I think the key is injecting in a >> persistence unit. >> >>> Hibernate has an EJB 3.0 implementation (both the OR >> annotations and >> >>> the entity manager). This will work pretty much the same >> as open JPA >> >>> (or any closed JPA :-), sorry couldn't resist it) >> >> Yes I think we want to have a generic integration if >> possible so we >> >> can use ClosedJPA too ;-) There may be some >> customizations we need >> >> for >> > >> >> particular vendor impls. >> >>> >> >>> May be we can have a framework that can support any JPA >> >>> implementation >> >> >> >>> make the EMF available as a system service. >> >> Yes agreed, although we may not want to say "EMF" since that may >> >> confuse people with Eclipse Modeling Framework :-) I'd >> also like to >> >> get a Hibernate integration going for people that like that API. >> >> >> >> Jim >> >> >> >>> >> >>> Ta >> >>> Meeraj >> >>> >> >>> >> >>>> From: Jim Marino <[EMAIL PROTECTED]> >> >>>> Reply-To: [email protected] >> >>>> To: [email protected] >> >>>> Subject: Re: EJB3 (JPA) support >> >>>> Date: Mon, 2 Oct 2006 10:30:20 -0700 >> >>>> >> >>>> Sure (since both you and Meeraj asked)... >> >>>> >> >>>> Basically, I think the use cases are pretty much the >> same for JPA, >> >>>> Hibernate, or JDO (not surprisingly): an application developer >> >>>> wants >> > >> >>>> to use a strongly-typed O/R mapper to persist data used >> within a >> >>>> service or composite implementation. They should be >> able to use any >> > >> >>>> of the JPA annotations to inject an entity manager onto >> a service >> >>>> instance: >> >>>> >> >>>> public class FooImpl extends Foo { >> >>>> @PersistenceUnit(name="example") >> >>>> protected EntityManager entityManager; >> >>>> >> >>>> } >> >>>> >> >>>> Hibernate would work the same way, except inject a >> Session. This >> >>>> would basically be an example of the "layering" >> approach to Java >> >>>> C&I >> > >> >>>> that we have discussed in the spec group. Under the >> covers, Tuscany >> > >> >>>> is managing instances of EntityManagerFactory as system >> services >> >>>> and >> > >> >>>> there is an annotation extension which is responsible for >> >>>> performing >> > >> >>>> the injection of EntityManager instances (non-thread-safe) onto >> >>>> component implementation instances. >> >>>> >> >>>> I would expect developers to use this approach when: >> >>>> >> >>>> - writing in Java or perhaps a "Java-friendly" language such as >> >>>> Groovy (obviously!) >> >>>> - they don't need to perform batch-oriented operations (JDBC is >> >>>> better for that) >> >>>> - they want to manipulate data in an O-O fashion as >> opposed to in a >> > >> >>>> loosely typed way or something like active record >> >>>> - they don't want to use declarative services, or they are not >> >>>> suited for an application's needs >> >>>> - they just like JPA or Hibernate for whatever reason >> >>>> >> >>>> From a non-technical perspective, this helps to embrace several >> >>>> communities by showing how their technologies are >> relevant in an >> >>>> SCA >> > >> >>>> environment. >> >>>> >> >>>> Jim >> >>>> >> >>>> >> >>>> >> >>>> >> >>>> >> >>>> >> >>>> On Oct 2, 2006, at 8:00 AM, scabooz wrote: >> >>>> >> >>>>> Hi Jim, >> >>>>> >> >>>>> This is the first time I've seen this topic discussed >> on the list. >> > >> >>>>> Apologies if I've missed it previously. Can you >> illuminate some >> >>>>> of >> > >> >>>>> your thinking behind it? I'm interested in >> understanding the use >> >>>>> cases you might be thinking of supporting, from at least the >> >>>>> perspective of the app developer. >> >>>>> >> >>>>> thanks >> >>>>> >> >>>>> Dave Booz >> >>>>> >> >>>>> >> >>>>> ----- Original Message ----- From: "Jim Marino" >> >>>>> <[EMAIL PROTECTED]> >> >>>>> To: <[email protected]> >> >>>>> Sent: Monday, October 02, 2006 3:24 AM >> >>>>> Subject: EJB3 (JPA) support >> >>>>> >> >>>>> >> >>>>>> Hi, >> >>>>>> >> >>>>>> I checked in a skeleton of EJB3 persistence support (using >> >>>>>> OpenJPA) that will leverage the system service work >> I just did. >> >>>>>> If anyone is interested in helping with this or adding in >> >>>>>> Hibernate support let me know. We may want to look >> at providing >> >>>>>> a >> > >> >>>>>> generic EJB3 JPA extension, although I'm not sure how much >> >>>>>> common >> > >> >>>>>> code would exist across implementations. >> >>>>>> >> >>>>>> Jim >> >>>>>> >> >>>>>> >> ----------------------------------------------------------------- >> >>>>>> - >> >>>>>> - >> >> >> >>>>>> -- >> >>>>>> To unsubscribe, e-mail: [EMAIL PROTECTED] >> >>>>>> For additional commands, e-mail: >> [EMAIL PROTECTED] >> >>>>> >> >>>>> >> >>>>> >> ------------------------------------------------------------------ >> >>>>> - >> >>>>> - >> >> >> >>>>> - >> >>>>> To unsubscribe, e-mail: [EMAIL PROTECTED] >> >>>>> For additional commands, e-mail: [EMAIL PROTECTED] >> >>>>> >> >>>> >> >>>> >> >>>> >> ------------------------------------------------------------------- >> >>>> - >> >>>> - >> >>>> To unsubscribe, e-mail: [EMAIL PROTECTED] >> >>>> For additional commands, e-mail: [EMAIL PROTECTED] >> >>>> >> >>> >> >>> _________________________________________________________________ >> >>> Get today's hot entertainment gossip >> http://movies.msn.com/movies/ >> >>> hotgossip >> >>> >> >>> >> >>> >> -------------------------------------------------------------------- >> >>> - >> >>> To unsubscribe, e-mail: [EMAIL PROTECTED] >> >>> For additional commands, e-mail: [EMAIL PROTECTED] >> >>> >> >> >> >> >> >> >> --------------------------------------------------------------------- >> >> To unsubscribe, e-mail: [EMAIL PROTECTED] >> >> For additional commands, e-mail: [EMAIL PROTECTED] >> >> >> >> >> >> This message has been checked for all email viruses by >> MessageLabs. >> >> >> >> >> >> >> >> >> >> ***************************************************** >> >> >> >> You can find us at www.voca.com >> >> >> >> ***************************************************** >> >> This communication is confidential and intended for the >> exclusive use >> >> of the addressee only. 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