Question

Is it possible to persist a generic field?

I have this property on an Entity class

...
private T payload;
...

T extends EventMessagePayload

and

public interface StringPayload extends EventMessagePayload{ 
    String getPayload();
}

In my application i persist the field only when is of String type and during the save operation all works great.

When I read the object instead JPA try to create a String object but instead is a StringPaylod. Is there a way to intercept the creation and handle the object marshalling?

Answer 1

JPA itself does not allow this, but your JPA implementation might allow it. We once did this with Hibernate, and it boilds down to implement your own EntityTuplizer (and a HibernateInterceptor to map your objects back to HibernateEntities).