<%
Client c = (Client)session.getAttribute("loggedClient");
if(c!=null) {
    // 1. Logged client -> cartSummary.jsp
    %> <jsp:forward page="/cartSummary.jsp" /> <%
} else {
    // 2. Un-Logged client -> register.jsp
    %> <jsp:forward page="/register.jsp?redirectPage=/cartSummary.jsp" /> <%
}
%>