sessao.setAttribute(SessionConstants.SESSION_IS_VALID, new Boolean(true));
	public ActionForward execute(		ActionMapping mapping,		ActionForm form,		HttpServletRequest request,		HttpServletResponse response)		throws Exception {		DynaActionForm autenticacaoForm = (DynaActionForm) form;		GestorServicos gestor = GestorServicos.manager();		Object argsAutenticacao[] =			{				autenticacaoForm.get("utilizador"),				autenticacaoForm.get("password")};		IUserView userView = null;		try {			userView =				(IUserView) gestor.executar(					null,					"Autenticacao",					argsAutenticacao);		} catch (Exception e) {			ActionErrors actionErrors = new ActionErrors();			actionErrors.add(				"invalidAuthentication",				new ActionError("errors.invalidAuthentication"));			saveErrors(request, actionErrors);			return mapping.getInputForward();		}		// Invalidate existing session if it exists		HttpSession sessao = request.getSession(true);//		if (sessao != null) {//			sessao.invalidate();//		}		// Create a new session for this user//		sessao = request.getSession(true);		// Store the UserView into the session and return		sessao.setAttribute(SessionConstants.U_VIEW, userView);		return mapping.findForward("SOP");	}