public class SessionManagerFilter implements Filter {
    /**
     * create a static reference to the logger.
     */
    private static final Logger logger = Logger.getLogger(SessionManagerFilter.class);

    private static final String FILTER_RUN = SessionManagerFilter.class.getName() + "FILTER_RUN";

    /**
     * Configures the filter.
     *
     * @param filterConfig the {@link javax.servlet.FilterConfig} to use.
     * @throws javax.servlet.ServletException {@link javax.servlet.Filter} related problems.
     */
    public void init(FilterConfig filterConfig) throws ServletException {
        logger.debug("init - start");
        logger.debug("init - end");
    }

    /**
     * Shuts down the filter.
     */
    public void destroy() {
        logger.debug("destroy - start");
        logger.debug("destroy - end");
    }

    /**
     * Executes the filter.
     *
     * @param servletRequest  the {@link ServletRequest} to use.
     * @param servletResponse the {@link ServletResponse} to use.
     * @param filterChain     the {@link FilterChain} to use.
     * @throws IOException      I/O related problems.
     * @throws ServletException {@link Servlet} related problems.
     */
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
            throws IOException, ServletException {

        logger.debug("doFilter - start");

        try {
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            HttpServletResponse response = (HttpServletResponse) servletResponse;

            HttpSession session = request.getSession();

            Boolean filterRun = (Boolean) session.getAttribute(FILTER_RUN);

            if (filterRun != null && filterRun.booleanValue()) {
                filterChain.doFilter(request, response);

            } else {

                // do the rest of the filter chain
                session.setAttribute(FILTER_RUN, Boolean.TRUE);

                filterChain.doFilter(request, response);

                if (session != null && !session.isNew()) {
                    session.removeAttribute(FILTER_RUN);
                }

            }

        } catch (Exception e) {
            logger.fatal(e.getMessage(), e);
            throw new ServletException(e.getMessage(), e);

        } finally {
            try {
                HibernateHelper.closeSession();
            } catch (Exception e) {
                throw new ServletException(e.getMessage(), e);
            } finally {
                logger.debug("doFilter - end");
            }
        }
    }
}