I am trying to build a BaseHibernateDAO. Looking at the caveatemptor example I wonder why no Base DAO was used? Do Hibernate guys dont like the idea? If yes any reason?

This is what I have come up with :

public interface BaseHibernateDAO {
public Serializable addObject( Object object ) throws InfrastructureException, DAOException;
public Serializable updateObject( Object object ) throws InfrastructureException, DAOException;
public void deleteObject( Object ) throws InfrastructureException, DAOException;
public Object retrieveObject( Class c, Long id ) throws InfrastructureException, DAOException;
public Collection findAll( Class c ) throws InfrastructureException, DAOException;
}


Thanks

No particular reason, there are many variations of the DAO pattern and all of them make more or less sense. Use what works best for you.

can u identify other variations? Thanks

ok i identify another variation. In it I define :
* a DAO fatory class
* a DAO interface
* a concrete class that implements the DAO interface
* data transfer objects

In this case for each Serializable class I have to define 3 classes. For example for MOVIE class, I have to define MovieDAOFactory, MovieDAO and MovieDAOImpl.

The variation I am using will need only one class MovieDAO which will be inherited from BaseHibernateDAOImpl.

what do you guys think?

I've come up with the following DAO library, relying on Java 1.5 generics. Showing only the main interfaces.

// Default DAO
public abstract class DAO<E,K extends Serializable> {
public E findById(K key) throws HibernateException {}
protected void save(E entity) throws HibernateException {}

public void update(E entity) throws HibernateException {}

public void update(Iterable<E> entities) throws HibernateException {}

public void delete(E entity) throws HibernateException { }

protected E find(String queryName,Object... args)
throws HibernateException {}

public List<E> findAll() throws HibernateException {}

protected List<E> query(String name,Object... parameters)
throws HibernateException {}
}

// creates a per-thread DAORegistry
public interface DAOService {
DAORegistry getDAORegistry() throws HibernateException;
}

// Opens Hibernate Session when needed,
// Instantiates DAOs on demand (if not already in registry)
public interface DAORegistry {
<T> T getDAO(Class<T> daoClass) throws HibernateException;
void close() throws HibernateException;
}