JPA2 + Hibernate + Order By

Question

Hi.

Is it possible (using Hibernate and JPA2 Criteria Builder [1]) to order by a method's result rather than an entity's member?

public class X {
    protected X() {}
    public String member;
    public String getEvaluatedValue() { // order by
        return "a status calculated with various members";
    }
}

What I want to achive is order by the result of getEvaluatedValue(). Is that possible?

Thanks in advanced.

EDIT: Added reply.

I'm not using @Formular, but

EntityManager em = ...;
QueryBuilder builder = em.getQueryBuilder();
SomeQueryClass query = builder.createQuery(MyTargetClass.class);
query.orderBy(builder.asc(... some code...));

I though it is plain JPA2 and certainly you are right there is no chance to order by dynamic data. But I may be allowed to specify some order-by block with an if-else or whatever statement (defined with my QueryBuilder), won't I?

[1] http://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html_single/#querycriteria

Answer 1

I don't know if it is possible (if an attribute is transient i.e. doesn't have a representation in database, what should be the SQL result?) but, more important, what would the difference between ordering by "some test " + member and member? Maybe that's just an example though...

Answer 2

Looks like it cannot be possible, for this reason : when the query is run in the SQL layer, the "EvaluatedValue" field is not calculated. It is only populated later (when exactly, I dont know, it may depend on if the entity uses a LAZY mode or not). The JPA Query object is closely tied to SQL, ie what is in the database.

Probably, I would get the non sorted results with a getResultList(), then manually sort them :

making your EvaluatedValue a type that implements Comparable : see here