Building a Simple Application - Beginning Hibernate: From Novice to Professional - page 49

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class DAO {
protected DAO() {
}
public static Session getSession() {
Session session = (Session) DAO.session.get();
if (session == null) {
session = sessionFactory.openSession();
DAO.session.set(session);
}
return session;
}
protected void begin() {
getSession().beginTransaction();
}
protected void commit() {
getSession().getTransaction().commit();
}
protected void rollback() {
try {
getSession().getTransaction().rollback();
} catch( HibernateException e ) {
log.log(Level.WARNING,"Cannot rollback",e);
}
try {
getSession().close();
} catch( HibernateException e ) {
log.log(Level.WARNING,"Cannot close",e);
}
DAO.session.set(null);
}
public static void close() {
getSession().close();
DAO.session.set(null);
}