[hibernate-dev] Integrator and retrieving objects

[Scott Marlow]

I like it.  I tried to do something generically in the AS7 JPA code to 
have a protected bag of such things at the container EntityManager 
level.  Just keep in mind that AS will try to serialize the objects when 
clustering.

See 
https://github.com/jbossas/jboss-as/blob/master/jpa/src/main/java/org/jboss/as/jpa/container/AbstractEntityManager.java 



    protected void addExtension(Class cls, Object extension) {
         extensions.put(cls, extension);
     }

   public <T> T unwrap(Class<T> cls) {
         Object x = extensions.get(cls);
         if (x != null)
             return (T) x;
         return getEntityManager().unwrap(cls);
     }


Also see some unwrap tests in 
https://github.com/jbossas/jboss-as/tree/master/testsuite/integration/src/test/java/org/jboss/as/testsuite/integration/jpa/hibernate

The SFSBHibernateSession test bean is based on the generic JPA 
EntityManager.unwrap(Class) we discussed before.

Scott

On 04/05/2011 03:19 AM, Emmanuel Bernard wrote:
> In JPA and other Java specs, there is a pattern emerging where one could unwrap some objects from a common API
>
> interface EntityManager {
>    T unwrap(Class<T>  type);
> }
>
> We typically let a Session be extracted from an EntityManager
>
> Session session = entityManager.unwrap(Session.class);
>
> I wonder if we want do provide a possibility for third party Hibernate integrators to let some objects be unwrapped.
>
> FullTextSession ftSession = session.unwrap(FullTextSession.class);
> //the current approach is via some static helper method
> //FullTextSession ftSession =  Search.getFullTextSession(session);
>
> That would mean that the integration point between HSearch and Hibernate would have an unwrap method and Hibernate would delegate the unwrap calls to each integrator until a non null object is returned.
>
> It's just a thought, WDYT?
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