Stateless DAO(EAO) versus POJO DAO

[Luciano A. Pozzo]

Is it better to use DAO as stateless or DAOs as POJO? What are the advantages and disadvantages?

thanks

[Jeanne Boyarsky]

Luciano,
It depends on what is in your DAO. Personally, I find it easier to write them as POJOs because I store state for the duration of the query. If your DAO is just a facade to something else (like a JPA entity), stateless is fine.

[Luciano A. Pozzo]

Hi Jeanne,

Actually I do not store state, only delegate queries for the EntityManager. Here's an example of DAO that I am currently using:

 
@Stateless
public class SomeDAO implements ISomeDAO {
@PersistenceContext 
        private EntityManager em;
 
public SomeEntity findByName(String name){
            return (SomeEntity )em.createQuery("from "+SomeEntity.class.getName()).getSingleResult();
}
}

But there came the idea of not using stateless, as example below:

 
public class SomeDAO implements ISomeDAO {
        private EntityManager em;
 
        public SomeDAO(EntityManager em){
            this.em = em;
        }
 
public SomeEntity findByName(String name){
            return (SomeEntity )em.createQuery("from "+SomeEntity.class.getName()).getSingleResult();
}
}
 
... Some Factory code here, to instanciate the DAOs(or EAOs).
 

The argument about this second way(just a POJO) is to improve performance.

Makes sense?

[Jeanne Boyarsky]

Originally posted by Luciano A. Pozzo:
The argument about this second way(just a POJO) is to improve performance.

Makes sense?

Kind of. It sounds like a case of premature optimization to me. If you have a problem with performance on that segment, sure. But I would think the database code would take many times longer than creating/injecting an object.

[Luciano A. Pozzo]

thank you for your opinion Jeanne.