Question

I have an Entity. And sometimes I need this object also contains some value, call it ‘depth’. The query may look like 'select b.id, b.name, b..., count(c.id) as depth from Entity b, CEntity c where ...'. So I’ve created class NonHibernateEntity which extends Entity. And then results of query written above are perfectly stored as List of NonHibEntity, which consists of all the fields of Entity (as they are extended), and property ‘depth’. I make it by setting aliasToBean results transformer: .setResultTransformer(Transformers.aliasToBean(NHEntity.class)).
But, it is annoying and inconvenient – to specify all the aliases of all the needed fields.
And then, if I want to save one of this object to DB – session.saveOrUpdate((Enity)nHibEntity) – there are an exception about nHibEntity isn’t Hibernate Entity.

I heard about storing ‘entity’ as field in NonHibEntity (aggregation, not inheritance). But it seems this is rather inconvenient too.
What do you think? What is an appropriate solution?

Answer 1

If somebody want to know – I solved this problem in such way:

just made this calculated field as @Transient, and then

List<BaseEntry> result = new ArrayList<BaseEntry>();
    Iterator it =  session()
    .createQuery("select b, (select count(p.id) as depth from BaseEntry p " +
            "   where ... ) as d" +
            " from BaseEntry b " +
            " where ... ")
    .list().iterator();
    while ( it.hasNext() ) {
        Object[] row = (Object[]) it.next();
        BaseEntry entry = (BaseEntry) row[0];
        Long d = (Long) row[1];
        entry.setD(d);
        result.add(entry);
    }
    return result;

It works good, and seems that it can be easily supported in future