Correct way to use a JPA*QueryVisitor with a filter class that is not a JPA entity

[Jim Talbut]

Hi,

I have a JPA data model that I'm trying to use with CXF's SearchContext.
In order to constrain the searching that can be done I'm trying to use a 
search class that is not a JPA entity (and that just contains a subset 
of the JPA fields).
Q1. Is this the right way to solve this problem?
Q2. How should I get it to work?

Details:

I have a "User" interface that the "User_JpaImpl" entity class derives from.
I also have a "UserFilter" class that just has two properties (username 
& enabled) - the User interface also has getters and setters for these 
properties, but there is no relationship between UserFilter and User (or 
User_JpaImpl).

My best attempt so far looks like this:
        SearchCondition<UserFilter> sc = 
searchContext.getCondition(UserFilter.class);
        JPACriteriaQueryVisitor<UserFilter, User_JpaImpl> visitor =
            new JPACriteriaQueryVisitor<>(entityManager, 
UserFilter.class, User_JpaImpl.class);
        searchCondition.accept(visitor);

        TypedQuery<User_JpaImpl> query = visitor.getTypedQuery();
        List<? extends User> result = query.getResultList();

This throws an exception in accept because of this:
        if (builder == null) {
            builder = em.getCriteriaBuilder();
            cq = builder.createQuery(queryClass);
            root = cq.from(tClass);
            predStack.push(new ArrayList<Predicate>());
        }

tClass is UserFilter.class, which is not known to JPA and thus cannot be 
used as root (cq.from(tClass) throws IllegalArgumentException).


All I want to do is limit the set of fields that can be queried, if this 
is the wrong approach I'm happy to swap it for another.

Thanks.

Jim