Is it possible to order by a composite key with JPA and CriteriaBuilder

Posted by Kjir on Stack Overflow See other posts from Stack Overflow or by Kjir
Published on 2012-04-15T10:46:57Z Indexed on 2012/04/15 11:29 UTC
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I would like to create a query using the JPA CriteriaBuilder and I would like to add an ORDER BY clause. This is my entity:

@Entity
@Table(name = "brands")
public class Brand implements Serializable {

    public enum OwnModeType {
        OWNER, LICENCED
    }

    @EmbeddedId
    private IdBrand id;
    private String code;
    //bunch of other properties
}

Embedded class is:

@Embeddable
public class IdBrand implements Serializable {

    @ManyToOne
    private Edition edition;
    private String name;
}

And the way I am building my query is like this:

CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Brand> q = cb.createQuery(Brand.class).distinct(true);
Root<Brand> root = q.from(Brand.class);
if (f != null) {
    f.addCriteria(cb, q, root);
    f.addOrder(cb, q, root, sortCol, ascending);
}
return em.createQuery(q).getResultList();

And here are the functions called:

public void addCriteria(CriteriaBuilder cb, CriteriaQuery<?> q, Root<Brand> r) {
}

public void addOrder(CriteriaBuilder cb, CriteriaQuery<?> q, Root<Brand> r, String sortCol, boolean ascending) {
    if (ascending) {
        q.orderBy(cb.asc(r.get(sortCol)));
    } else {
        q.orderBy(cb.desc(r.get(sortCol)));
    }
}

If I try to set sortCol to something like "id.edition.number" I get the following error:

javax.ejb.EJBException: java.lang.IllegalArgumentException: Unable to resolve attribute [id.name] against path

Any idea how I could accomplish that? I tried searching online, but I couldn't find a hint about this... Also would be great if I could do a similar ORDER BY when I have a @ManyToOne relationship (for instance, "id.edition.number")

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