Hibernate version:
3.1beta1

Code:

Object rslt = session.load(SomeClass.class, itemId);
session.setReadOnly(rslt, true);

Stack trace of any exception that occurs:

org.hibernate.TransientObjectException: Instance was not associated with the session
org.hibernate.engine.StatefulPersistenceContext.setReadOnly(StatefulPersistenceContext.java:1134)
org.hibernate.impl.SessionImpl.setReadOnly(SessionImpl.java:1524)
.
.
.

Name and version of the database you are using:
MySQL 4.1.12a


I am trying to switch off the feature of Hibernate, which will save automatically the object (with its changed properties) retrieved by session.load() to DB when the session is flushed. I can not detach the object as I would like use the lazy collections feature, but I would like to make modifications to loaded object without saving it to DB (a sort of preview...)

This seemed to me the right way according to JavaDocs, but it looks like it is not...

Try session.evict()

thank you very much, but this makes my lazy collections - which I like quite a lot - not working anymore, especially as I am using the Open Session in View approach with org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor

I was trying to find the problem with setReadOnly in the source code, but unfortunatelly I got lost too early...

after some modifications in the code I have found that if I add

@org.hibernate.annotations.Proxy(lazy=false)

to the class, which instance I am trying to make read-only, it works the right way. Looks almost like a bug.

anyway I bumped straight to another issue, as I would like to have in one session one instance with old values (as they are saved in the DB at that tome) and also another read-only copy of that instance, with applied modifications as a sort of preview-new-modifications-and-compare-with-previous-state matter.

so basically I am doing this

Object new = session.load();
session.setReadOnly(new, true);
new = makeTheModifications(new);
Object old = session.load();

but unfortunatelly this is not working, probably due to some cache reasons so even if I have the following code snippet

getSessionFactory().evict(SomeClass.class, itemId);
Session session = SessionFactoryUtils.getSession(getSessionFactory(), false);
session.setCacheMode(CacheMode.IGNORE);
Object rslt = session.load(SomeClass.class, itemId);
getSessionFactory().evict(SomeClass.class, itemId);
rslt = session.load(SomeClass.class, itemId);

the second load() call will not force the item to reload from DB = second SQL statement. Therefore I am not able to get the original state again from DB.

I can not use session.reload() as this will refresh both the copies of the object.

I can not use session.evict() as mentioned earlier.

I can not make directly some sort of copy of the object before applying modifications, because the first load() and the second load() actually happens on completely different places. If you know Spring Web MVC, then first is in formBackingObject method to create the command object (for applying modifications) and the second one is in onSubmit method to create the object with current (old) values from DB. Applying of the modifications to the command object is located (as usually in Spring Web MVC) in the onBind method which is called before onSubmit and after formBackingObject. So if I would be able to make copy in the formBackingObject, I have to solve how to get it into the onSubmit method in some nice and clear way...