Classbridge - "indexed embedded" polymorphic use case

darioc · **Joined:** Wed Aug 06, 2014 10:53 am **Posts:** 30

Hi All,
I'm trying to index my JournalLogItem with a linkedentity (like a IndexedEmbedded).

I'll try to show my use case with an example:

Code:

@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class AbstractEntityModel(){
}

public class AddressEntity extends AbstractEntityModel(){
}
public class CarEntity extends AbstractEntityModel(){
}


@Indexed
@Entity
@ClassBridges({ @ClassBridge(name = "MyCustomFieldBridge", impl = MyCustomFieldBridge.class) })
public class JournalLogItem (){

  @IndexEmbedded
  private AbstractEntityModel linkedEntity;

  private String linkedEntityClassName;
  private String linkedEntityId;

  @CustomEntityField(classDiscriminatorField = "linkedEntityClassName", entityIdField = "linkedEntityId")  
  public AbstractEntityModel getLinkedEntity(){
    // ?? how can I return the correct entity? 
  }
  
}

public class MyCustomFieldBridge implements FieldBridge {
  @Override
  public void set(String name, Object value, Document document, LuceneOptions luceneOptions) {
    if (value instanceof JournalLogItem ) {
      // ?? Can I access to PersistenceContext?
    }
  }
}

How can I return the correct linked entity?
By a custom ClassBridge can I get the entity from the PersistenceContext? Is there a way to get the actual PersistenceContext from FieldBridge?

Thanks,
dario

Gunnar · **Joined:** Sat Jan 24, 2009 12:46 pm **Posts:** 388

Let's take a step back, what is the use case you are actually trying to implement, i.e. what are the requirements here? Knowing this will help to find a good solution.

Btw. it seems you try build some sort of auditing mechanism, have you looked into Hibernate Envers?

--Gunnar

sanne.grinovero · **Posted:** Wed Feb 03, 2016 11:24 am

Quote:

By a custom ClassBridge can I get the entity from the PersistenceContext?

That's what you get in the "Object value" parameter of the ClassBridge method:

Code:

public void set(String name, Object value, Document document, LuceneOptions luceneOptions)

N.B. when you use a ClassBridge you have to encode all fields on your own, so for example the @IndexEmbedded on linkedEntity will be ignored.

darioc · **Joined:** Wed Aug 06, 2014 10:53 am **Posts:** 30

Hi,
my use case is not a auditing mechanism. I already use Hibernate Envers for that scope.

I have a linked abstract entity: I need to indexing this entity at runtime when I will know his classname.
I resolved the issue using @Any/@AnyMetaDef hibernate annotation to describe this kind of relation. Now seem it working.

My doubt is: Can I access to EntityManager during the indexing from the "set" method of the classbridge?

@Sanne wrote: "N.B. when you use a ClassBridge you have to encode all fields on your own, so for example the @IndexEmbedded on linkedEntity will be ignored."
I have a question: The @ContainedIn mechanism is ignored when the ClassBridge is defined? I just bumped another problem.. I'll open another thread for that.

Dario

sanne.grinovero · **Posted:** Thu Feb 04, 2016 5:52 pm

Quote:

My doubt is: Can I access to EntityManager during the indexing from the "set" method of the classbridge?

The short answer is no. Normally I'd expect the entity to have all information you need; is the question you need to run additional queries on the database?
It is ok to walk relations of the entity, even if they are lazy-loaded.
Another trick is to have some @Transient getters on the entity, were you can store additional metadata which you might need at indexing time.

darioc · **Joined:** Wed Aug 06, 2014 10:53 am **Posts:** 30

Hi Sanne,
I'll keep it in mind!

I already used transient fields for that scope. Thanks for your suggestions!