Hey all,

I'm trying to build a 3 tier application with hiberante for persistence. I'm currently experimenting if I could use the objects I get from Hibernate directly in all the layers.

One thing I'm constantly bumping my head against is that hibernate instantiates lazy loaded collections from the object cache even if I explicitly request that collection to stay empty (outer-join=false, lazy=true).

Is there a way I can specify (in HQL or otherwise) a collection to stay empty while retireving the object? I tried adding the following to my sql statement:

select c from nl.s.g.customer as c left outer join projectSet as p where c.code='12345' and p.code = ''

p.code cannot be an empty string, so this should initialize c with an empty collection of projects. But then no records are returned.

If I just ask for

from nl.s.g.customer as c where c.code='12345'

I get a customer with a lazy loaded projectset which is empty most of the time unless one or more projects of this customer are in the cache, the objects in cache will be added to the Customer (eventhough those are NOT all the objects that belong in that collection).

So my question is:
How can I get an object from the database with an empty collection of child objects?

This is not the case in current CVS, and I don't think it is true of 2.1.2 either.

I am using 2.1.2, but I tried again to be sure.

If I do the following:

create a customer
open session
save the customer
close session
open session
create a project with a name and the associated customer
save the project
create a project with a name and the associated customer
save the project
close session

open session
load the customer with lazy set of projects
close session
check number of projects: 2
toString the values of projects works

Debug log states: associating from cache for each project.

I found a way around this by using iunterceptors, they make sure now that the collection stays empty when it must,

It is on cache, so you don't hit the DB to get your collection.
If you don't want to use second level cache, then remiove it from your mapping files.

Ok, fixed this.

I do have a very similar problem. I've created an interceptor for a couple of types I'm using that are secured (with a custom security model). I'd like to be able to deny access to certain objects that are stored using hibernate based on properties in the class.

I've looked around and found a partial implementation of this on the wiki here.

But this doesn't seem to work as described. When doing a query to load a number of objects of a certain type (eg: From objectA) with at least one object that violated the check the whole list comes up empty. I'd like it to return all valid typed, except the objects that threw an exception during load.

I've read on the blog that there are plans to include something like this in hibernate 2.2/3.0. I looked at the source in the CVS, but couldn't find something liek this.

Is there a way this can be done? Or will I have to put the security exclusively in a higher layer?[/url]

For now put it at a higher level

Doing that now, but it a pain ;)

Is support for this planned? I think I read something like this on the blog a few weeks back, but can't seem to find it now.

That's the one, glad to see it will come in the future, but it will unfortunately too late for me ;(. Ohh well, nice for the next project