public List executeQuery (ObjectContext context, QuerySpecification spec)
{
CompassSession session = getCompass(context).openSession();
CompassTransaction tr = session.beginTransaction();
CompassQueryBuilder builder = session.queryBuilder();
CompassQuery query = queryForPredicate(builder, spec.getPredicate());
Class targetClass = ClassUtil.classForName(spec.getEntityName());
query.setTypes(targetClass);