* @throws ServletException if a servlet exception ocours
*/
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) servletRequest;
AttributeContainer sessionWrapper = (AttributeContainer) HttpSessionWrapper.wrapItIfNecessary(req.getSession());
if (!Config.getInstance().isEnabled() || !NavigationManagerFactory.existsInstance(sessionWrapper)) {
filterChain.doFilter(servletRequest, servletResponse);
} else {
NavigationManager navigationManager = NavigationManagerFactory.getInstance(sessionWrapper);