Hello everybody,

I'm using hibernate 3.1 in a web application with javaserver faces.
I use a thread local session and a servlet filter to close the session at the end of the request, so that I can access my objects from the jsp files.
I have the following mapping files:

<class name="User" table="User">
<set name="items" table="Item" >
<key column="userId"/>
<one-to-many class="Item"/>
</set>
...
</class>

<class name="Item" table="Item">
<many-to-one name="a" class="A">
<column name="aId" not-null="true"/>
</many-to-one>
...
</class>

<class name="A" table="A">
<many-to-one name="b" class="B">
<column name="bId" not-null="true"/>
</many-to-one>
...
</class>

<class name="B" table="B">
<property name="name" type="string">
<column name="name" length="128" not-null="true"/>
</property>
...
</class>

What I want to do in my jsp is:

<h:dataTable value="#{bean.items}" var="item">
<h:column>
<h:outputText value="#{item.a.b.name}" />
</h:column>
</h:datatable>

in my bean i have:
user = (User) session.get(User.class, id);
bean.getItems.addAll((user.getItems()))

and i get this exception:

javax.faces.el.EvaluationException: javax.faces.el.EvaluationException: Error getting property 'b' from bean of type mypack.domain.A$$EnhancerByCGLIB$$2e8df83: org.hibernate.LazyInitializationException: could not initialize proxy - the owning Session was closed.

All my associations are lazy but since my session is not closed it should be possible to load a,b and title in my jsp.
What is wrong with this?

Thank you in advance

I'd check your code again, because the session that loaded the object is closed.
1) make sure that it's the same session (should be, if you are using a thread local) and
2) make sure that the OSIV filter is the topmost filter (I'm not that familiar with JSF, but if it uses a filter, make sure it is chained inside of the OSIV filter) and lastly
3) don't use OSIV, hydrate your objects with as much info as you need for the view and then pass it to the UI layer

I used to use OSIV, but it's a pain to debug, breaks encapsulation/separation of concerns (IMHO, don't grief me on this!) and you need yet another filter to trap any exceptions that occur in the lazy loading of the view! Ick! If it looks like an anti-pattern, smells like and anti-pattern and feels like an anti-pattern... ;D

It's a pattern that is used in almost all Hibernate applications with great success. You do _not_ catch LazyInitializationException. That is the whole point of the pattern. There is ready to use code linked here: http://hibernate.org/42.html

Thank you for reading my post and your replies,

so from your answers and having read the documents on the site I get that my code should be working. For some reason though my session is closed during the rendering of the view. I will look into it.

Thank you!

Don't worry brother, I was just poking fun, that's what my winky emoticon was for :D. My UI jockeys wouldn't know an N+1 selects problem if it bit them in the rear. If I don't completely fill out relevant objects graphs for them my database server would be hella pissed!

I find that OSIV is fine if your backend and UI programmers are one and the same person, but on more complex projects where concerns are highly delineated, you just end up forcing your UI developers to learn complex SQL concepts. My current project is 380 ridiculously overengineered tables (the DBAs had two years to make as much of a mess as possible), and there's no way I'd let the UI guys navigate a lazy-loaded domain graph.