Extension points - Tupilizer/Instantiator/EntityMode

mveitas · **Posted:** Mon Mar 07, 2005 10:43 am

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Hibernate version:
Hibernate 3.0 rc1

I am trying to extend the Hibernate framework to allow me to read and write my own custom version of what essentially is a Map. I used to use the Interceptor just fine with Hibernate3 Beta 1, but it is not working anymore.

I did some digging to find new interfaces, Tupilizer and Instantiator. Can you provide some feedback as to how to use these and where I can plug them into the framework? I have created a Tuplizer and Instantiator for my custom objects, but can't find the place to plug them in. Is there a way to create my own EntityMode?

Code:

Configuration config = new Configuration().configure( new File( hibernateConfigFile ) );
config.setInterceptor( new MetaObjectInterceptor() );

sessionFactory = config.buildSessionFactory();

MetaKit metaKit = new MapMetaKit( null );
MetaObject metaObject = metaKit.getMetaObjectFactory().createMetaObject( metaClass );
metaObject.setProperty( "name", "Engine 611" );
metaObject.setProperty( "unitType", "Engine" );
metaObject.setProperty( "stationNumber", new Integer( 11 ) );
metaObject.setProperty( "gallonsOfWater", new Integer( 750 ) );
metaObject.setProperty( "singleAxle", Boolean.TRUE );

Session session = sessionFactory.openSession();
Session mSession = session.openSession( EntityMode.MAP );
Transaction tx = session.beginTransaction();
mSession.saveOrUpdate( metaObject );
session.flush();
tx.commit();
session.close();

steve · **Posted:** Mon Mar 07, 2005 9:23 pm

Eventually these will be extension points hopefully. Currently they are not per-se. To use them you'd really have to modify the Hibernate sources. Specifically, take a look at persister/BaseEntityPersister and tuplizer/TuplizerLookup. The easiest option would be to simply modify the MapTuplizer stuff to perform your needed functionality.

mveitas · **Posted:** Mon Mar 07, 2005 9:35 pm

I think that I have a stop gap solution until the Hibernate team makes these extension points, someday ;). Not sure if there are plans for documenting the extension points in more detail, but I think that would be a great addition to the reference docs.

The functionality that we are looking for with Hibernate to do the reading/writing of these custom objects is minimal. What I have done is to create my own Tuplizer and Instantiator, and then extend SingleTableEntityPersister to create use the custom Tuplizer that I created. So far simple reads and writes of objects work just fine. I am going to look into more complex things like components and such this week.

Great work with Hibernate 3 so far....I can't wait to start using some of the new features!

steve · **Posted:** Mon Mar 07, 2005 10:24 pm

Well there's always plans to document extension points; but like I said these are not currently intended as extension points ;)