Onde fechar a session hibernate + JSF

<filter>
        <filter-name>HibernateSessionFilter</filter-name> 
        <filter-class>br.bd.HibernateSessionFilter</filter-class> 
    </filter>  
    <filter-mapping>
        <filter-name>HibernateSessionFilter</filter-name> 
      <url-pattern>/faces/*</url-pattern>
    </filter-mapping>

package br.bd;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
public class HibernateSessionFilter implements Filter {
        @Override
	public void doFilter(ServletRequest req, ServletResponse res, FilterChain fc) throws IOException, ServletException {
		HibernateUtil.openSession();
		try {
			HibernateUtil.currentSession().beginTransaction();
			fc.doFilter(req, res);
			HibernateUtil.currentSession().getTransaction().commit();
		} catch (Exception e) {
			HibernateUtil.currentSession().getTransaction().rollback();
			throw new ServletException(e);
		} finally {
			HibernateUtil.closeCurrentSession();
		}
	}
	
        @Override
	public void init(FilterConfig c) {	
	}

        @Override
	public void destroy() {	
	}
}