用hibernate实现基于集合的(ddd)存储库

我想看看是否可以将存储库实现为 java.util.Collection (很可能是 Map )

大致如下:

@Repository
public abstract class HibernateRepository<K extends Serializable, V>
    extends AbstractMap<K, V> {

    @Autowired
    private SessionFactory sessionFactory;

    private Class<K> keyClass;
    private Class<V> valueClass;

    public HibernateRepository(Class<K> keyClass, Class<V> valueClass) {
        this.keyClass = keyClass;
        this.valueClass = valueClass;
    }

    @Override
    @SuppressWarnings("unchecked")
    public V get(Object key) {
        return (V) sessionFactory.getCurrentSession()
                                 .get(valueClass, (Serializable) key);
    }

    @Override
    @Transactional
    public Set<java.util.Map.Entry<K, V>> entrySet() {
        return new EntrySet(sessionFactory.getCurrentSession());
    }

    private class EntrySet extends AbstractSet<java.util.Map.Entry<K, V>> {

        private Session session;

        public EntrySet(Session session) {
            this.session = session;
        }

        @Override
        public Iterator<java.util.Map.Entry<K, V>> iterator() {
            // Hibernate Criteria doesn't do Iterator
            // so would probably a fair bit of manual work
            // if multiple DB requests are to be avoided
        }
        @Override
        public int size() {
            return (Integer) session.createCriteria(valueClass)
                                    .setProjection(Projections.rowCount())
                                    .uniqueResult();
        }
    }
}

public class FooRepository extends HibernateRepository<Integer, Foo> {
    public FooRepository() { super(Integer.class, Foo.class); }

    // domain specific queries/methods...
    public Foo findMagicOne(....) { ... }
}

显而易见的问题是

• 尽量避免向数据库提出愚蠢的请求
• 同步化

在我的域模型中,很多时候将db视为list/map/set是有用的,因此尝试使用标准java.util接口来实现这一点似乎是明智的。

有这样的例子吗?我是不是要趴在地上,去做像推 Comparable.compareTo 通过Hibernate操作到数据库?