public class HibernateUtil {

    private static SessionFactory sessionFactory;

    public static synchronized void buildSessionFactory() {
        if (sessionFactory == null) {
            Configuration configuration = new Configuration();
            configuration.configure();
            configuration.setProperty("hibernate.current_session_context_class", "thread");
            ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry();
            sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        }
    }

    public static void openSessionAndBindToThread() {
        Session session = sessionFactory.openSession();
        ThreadLocalSessionContext.bind(session);
    }


    public static SessionFactory getSessionFactory() {
        if (sessionFactory==null)  {
            buildSessionFactory();
        }
        return sessionFactory;
    }

    public static void closeSessionAndUnbindFromThread() {
        Session session = ThreadLocalSessionContext.unbind(sessionFactory);
        if (session!=null) {
            session.close();
        }
    }
    
    public static void closeSessionFactory() {
        if ((sessionFactory!=null) && (sessionFactory.isClosed()==false)) {
            sessionFactory.close();
        }
    }    
}