Hi

I'm using Hibernate version 2.1.2, MySQL version 4.0.18

I have a question regarding long transactions using session.disconnect() and session.reconnect(). Is it dangerous to simply make a method that returns the session in a disconnected state, and whenever I make a connection to the DB I reconnect, do what I want, and then diconnect like this:

//+ imports;

public class UserService
{

public User getUser(String userName)throws HibernateException
{
User user = null;
Session session = HibernateUtilities.currentSession();
session.reconnect();
String hql="from people.Person as user where" + "userName='"+userName+"'";
List list = session.find(hql);
for(Iterator iter = list.iterator();iter.hasNext();)
{
user = (User)iter.next();
}
session.disconnect();
return user;
}end getUser

public void saveOrUpdateToDatabase(Object object) throws HibernateException
{
Session session;
Transaction transaction = null;
try {
session = HibernateUtilities.currentSession();
session.reconnect();
transaction = session.beginTransaction();
session.saveOrUpdate(object);
transaction.commit();
session.disconnect();
} catch (HibernateException e) {

if(transaction!=null)
transaction.rollback();
e.printStackTrace();
}
} // end saveToDatabase

}

//+imports

public class HibernateUtilities {

private static final SessionFactory sessionFactory;

static {
try {
sessionFactory = new Configuration()
.configure().buildSessionFactory();
} catch (HibernateException ex) {
throw new RuntimeException(
"Exception building SessionFactory: " + ex.getMessage(), ex);
}
}

public static final ThreadLocal local = new ThreadLocal();

//Returns a disconnected Session object
public static Session currentSession() throws HibernateException {
Session session = (Session) local.get();

if (session == null) {
session = sessionFactory.openSession();
session.disconnect();
local.set(session);
}
return session;
}

public static void closeSession() throws HibernateException {
Session session = (Session) local.get();
session.reconnect();
local.set(null);
if (session != null)
session.close();
}
}

I experience no problem doing it like this, but i wonder if it is not the most efficent way around.. Also I'm not sure if it is ok to load an object from a database lik I do in getUser(String userName), work with it an its lazy collections, and then update it in DB using the method saveOrUpdateToDatabase(Object object)..


--dag--

String hql="from people.Person as user where userName= :userName'";
Query q = session.createQuery(hql);
q.setProperties("transferBean); --> look at query API
List list = query.list();
user = (User)list.get(0);

Only use iterate() method when you need because it execute one sql query per result to have the detail.
List() method execute only one optimised sql query.


If userName is the id then use session.load(....)

oh, i forgot, you should consider using transaction even for read-only code