Using Hibernate 3.2.5

We have entities User, Role, Group. The User class has a Map of Roles to sets of Groups. Since the value class of a map must be a mapped entity itself, we created another mapped entity "GroupSet".

class User {
private Map<Role,GroupSet> groups;
}

class GroupSet {
private Set<Group> groups;
}

So now - how to find the users for a given group? These relationships are unidirectional (User -> groups, GroupSet -> groups). So we're going to do an HQL query:

public List<User> getGroupMembers(Group group, Role role) {
String hql =

"from User user where ? in elements(user.groups[?].groups)";

return getHibernateTemplate().find(hql, new Object[] {group, role });
}


Very nice! Except it doesn't work :( Evidently the HQL parser cannot handle the above:

org.hibernate.hql.ast.QuerySyntaxException: expecting CLOSE, found '[' near line 1, column 78 [from User user where ? in elements(user.groups[?].groups)]

Now I know this expression is being interpreted correctly, I can do things like this:


"from User user where user.groups[?].groups.size > 1"

and that runs just fine...

So - is this a bug in Hibernate? Shouldn't I be able to pass the elements function an expression like user.groups[?].groups ??

If not, what is the work-around here?

Kind regards :)

Ossie

Yeah the mappings are straightforward enough:

from User.hbm.xml:

<map name="groups" table="USER_GROUPS" lazy="false" cascade="all">
<key column="USER_ID"/>
<map-key-many-to-many column="ROLE_ID" class="Role"/>
<many-to-many column="GROUP_SET_ID"class="GroupSet"/>
</map>

from GroupSet.hbm.xml:

<set name="groups" table="GROUP_SET_GROUPS" lazy="false">
<key column="GROUP_SET_ID"/>
<many-to-many column="GROUP_ID" class="Group"/>
</set>

And again, the query *seems* straightfoward:

from User user where ? in elements(user.groups[?].groups)

I realize the [] notation is restricted to WHERE clauses, but that's where it is!

Is there really nobody out there with some insight on this one?

Cheers!

Ossie