JPA SingularAttribute on Criteria Query

criteria.java

public abstract class GenericDAOImpl<T extends DomainObject, T2 extends DomainObject> implements GenericDAO<T, T2> {

private Class<T> type;

@PersistenceContext
protected EntityManager entityManager;

public GenericDAOImpl(Class<T> type) {
    super();
    this.type = type;
}

... save and delete classes go here

@Override
public List<T> findAll(T2 where) {

    CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
    CriteriaQuery<T> criteriaQuery = criteriaBuilder.createQuery(type);
    Root<T> rootQuery = criteriaQuery.from(type);
    if (where != null) {

        EntityType<T> entity = entityManager.getMetamodel().entity(type);

        SingularAttribute<? super T, ?> attribute = null;
        for (SingularAttribute<? super T, ?> singleAttribute: entity.getSingularAttributes()) {
            // loop through all attributes that match this class
            if (singleAttribute.getJavaType().equals(where.getClass())) {
                // winner!
                attribute = singleAttribute;
                break;
            }
        }
        // where t.object = object.getID()
        criteriaQuery.where(criteriaBuilder.equal(rootQuery.get(attribute), where));
    }
    criteriaQuery.select(rootQuery);
    TypedQuery<T> query = entityManager.createQuery(criteriaQuery);

    // need this to make sure we have a clean list?
    // entityManager.clear();
    return query.getResultList();
}