Hibernate cache na sessao

package br.com.cultura.sisint.dao;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;


/**
 * Classe utilitaria para manipulacao das sessoes com o Hibernate.
 * 
 * 
 */
public class DAOSession {
	
	private static SessionFactory SF;

	static {
		AnnotationConfiguration cfg = new AnnotationConfiguration();
		try {

			SF = cfg.configure().buildSessionFactory();
			
		} 
		catch (HibernateException e) {
		    throw new RuntimeException(e.getMessage());
		}
	}

	public static final ThreadLocal session = new ThreadLocal();

	/**
	 * Cria uma nova sessao.
	 */
	@SuppressWarnings("unchecked")	
	public static void openSession() {
		try {
			session.set(SF.openSession());
		} 
		catch (Exception e) {
			throw new RuntimeException(e.getMessage());
		}
	}
	
	/**
	 * Retorna a sessao atual.
	 * @throws RuntimeException	se o método for chamado e não existir uma sessão.
	 */	
	@SuppressWarnings("unchecked")
	public static Session currentSession() {
		Session s = (Session) session.get();
        // Open a new Session, if this Thread has none yet
        if (s == null) {
            s = SF.openSession();
            session.set(s);
        }

		return s;
	}

	/**
	 * Fecha a sessao atual.
	 */	
	@SuppressWarnings("unchecked")	
	public static void closeSession() {
		try {
			Session s = currentSession();
			session.set(null);
			s.flush();
			s.close();
		} 
		catch (Exception e) {
			throw new RuntimeException(e.getMessage());
		}
	}
	public static void hsqlCleanup(Session s) {
	    try {
	        s.connection().createStatement().execute("SHUTDOWN");
	    } catch (Exception e) {
	    }
	}

}