Loading javassist-ed Hibernate entity

Question

I have a JSF converter that I use for a SelectItem list containing several different entity types. In the getAsString() method I create the string as the class name suffixed with ":" and the ID.

MySuperClass superClass = (MySuperClass)value;
if(superClass != null) {
  return String.valueOf(superClass.getClass().getName()+":"+superClass.getId());
}

This allows me to load the correct entity in the getAsObject() on the way back from the UI by doing this :

String className = value.substring(0, value.indexOf(":"));
long id = Long.parseLong(value.substring(value.indexOf(":")+1));
Class<T> entitySuperClass = (Class<T>) Class.forName(className);
MySuperClass superClass = (MySuperClass)getEntityManager().find(entitySuperClass, id);

My problem is that my entity in getAsString() is a proxy. So instead of getting com.company.MyEntity when I do a getClass().getName() I am getting com.company.MyEntity_$$_javassist_48 so then it fails on the find().

Is there any way (aside from String manipulation) to get the concrete class name (eg. com.company.MyEntity)?

Thanks.

Answer 1

Instead of superClass.getClass() try org.hibernate.proxy.HibernateProxyHelper.getClassWithoutInitializingProxy(superClass).

Answer 2

There is one important difference between Hibernate.getClass() and HibernateProxyHelper! The HibernateProxyHelper always returns the superclass that represents the table in the database if you have and entity that is mapped using

@Table(name = SuperClass.TABLE_NAME)
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = SuperClass.TABLE_DISCRIMINATOR, discriminatorType = DiscriminatorType.STRING)

and

@DiscriminatorValue(value = EntityClass.TABLE_DISCRIMINATOR)

in the subclass.

Hibernate.getClass(...) returns the real subclass for those.

Answer 3

When combined with abstract entity's inheritance (AbstractEntity <- ConcreteEntity <- ConcreteEntityProxy), getting the persistence class is just not enough:

// This should fail - trying to create an abstract class
HibernateProxyHelper.getClassWithoutInitializingProxy(superClass).newInstance()

instead get the implementation class:

protected <T> T deproxy(T maybeProxy) {
    if (maybeProxy instanceof HibernateProxy) {
        return (T) ((HibernateProxy) maybeProxy).getHibernateLazyInitializer().getImplementation();
    }
    return maybeProxy;
}