Extendending Hibernate Generated Classes

Acco Lade · **Joined:** Fri Apr 02, 2004 3:34 am **Posts:** 40

Hi,

I used hbm2java to generate a bunch of classes. Now, I am thinking about hand-coding a few classes that will derive from the auto-generated classes.

So, I can use Hibernate to persist my hand-coded classes? Are there any restrictions? I figure the new fields won't be persisted, but are there any other issues?

How about retrieval? I figure I cannot cast one of the auto-gen classes to my hand-coded class?!?

Thanks,
Acco

anthony · **Posted:** Sat Apr 03, 2004 4:31 am

Quote:

I figure the new fields won't be persisted

are the new fields stored on db?
if yes just take a look at subclass, joined-subclass in the doc

Acco Lade · **Joined:** Fri Apr 02, 2004 3:34 am **Posts:** 40

Nope, the fields are transient. For example,

class Cat; // persistent per Hibernate Example.

class MyFatCat extends Cat;

Now, everytime I retrieve Cat (reads from the Cat table), I would the class returned to be MyFatCat and not Cat, is that possible?

For this particular example below,

Cat cat = (Cat) firstSession.load(Cat.class, catId);

it looks like I can use MyFatCat.class, but how about the more general cases? Like when the cats in are in a collection, will the type be Cat or can I specify it to be MyFatCat?

Note: I would like to achieve this without modifying the hbm mapping files at all.

Thanks,
Acco

emmanuel · **Posted:** Mon Apr 05, 2004 7:33 am

Will work, except

Code:

session.load(MySubclass.class, classId);

You should use

Code:

session.load(MyClass.class, classId);

Not sure of that but check.