Re: Code generation tool for persitence layer (from database)

Well, already by using an ORM like EclipseLink you don't have to write
SQL to do deletes/updates/inserts right?

So what code are you trying to generate for DAO's? a call to
entityManager.merge?

Your DAO is independent of any specific entities, so you don't need to
make 30 different implementations of it.

Here's an example of a SimpleDAO that I use on it's own or extend if I
need a special one.

(Ignore Spring annotations, and you may have to change you you obtain
your entity manager if you're not using spring dependency
injection...)



import java.util.List;

import javax.annotation.PostConstruct;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceUnit;
import javax.persistence.Query;

import org.eclipse.persistence.jpa.JpaEntityManager;
import org.eclipse.persistence.jpa.JpaHelper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.orm.jpa.JpaCallback;
import org.springframework.orm.jpa.support.JpaDaoSupport;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

@Transactional
@Repository
public class SimpleDao {
       
        @PersistenceContext
        private EntityManager entityManager;


        public EntityManager getEntityManager()
        {
                return entityManager;
        }
       
        @Transactional(propagation=Propagation.REQUIRED)
        public void insert(Object entity)
        {
                entityManager.persist(entity);
        }
       
        @Transactional(propagation=Propagation.REQUIRED)
        public <T> T save(T entity)
        {
                return entityManager.merge(entity);
        }
       
        @Transactional(propagation=Propagation.REQUIRED)
        public void delete(Object entity)
        {
                entityManager.remove(entity);
        }
       
        @Transactional(readOnly = true)
        public <T> T find(Class<T> entityClass, Object primaryKey) {
                return entityManager.find(entityClass, primaryKey);
        }


        @Transactional(readOnly = true)
        public <T> List<T> selectAll(Class<T> clazz) {
                return (List<T>)
JpaHelper.getEntityManager(entityManager).createQuery(null,
clazz).getResultList();
               
                JpaHelper.getEntityManager(entityManager).createQuery(null, clazz).set
        }
       


}



./tch



On Mon, Nov 24, 2008 at 9:18 AM, Chiovari Cristian Sergiu
<csergiu77@...> wrote: _______________________________________________
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