<%
  String login = (String)session.getValue("login");

  if ( login == null) {
    StringBuffer loginpoint = new StringBuffer();

    loginpoint.append(request.getScheme())
              .append("://")
              .append(request.getServerName())
              .append(request.getRequestURI());

  session.putValue("loginpoint", loginpoint.toString());

    StringBuffer loginpage = new StringBuffer();

    loginpage.append(request.getScheme())
             .append("://")
             .append(request.getServerName())
             .append("/")
             .append("login.jsp");

    response.sendRedirect(loginpage.toString());
  } 
%>