How to prevent login page in same browser when user is already authenticated

Question

Hello,
I am using Jdev 11.1.1.6 with ADF security implemented in my application.
I have Login.jspx that redirects the user to Home.jspx on successful authentication. User can either enter Login or Home Page URL.
Please consider following scenarios:
a) User is not authenticated in current browser session
  a.1) if user enters Home page URL then Login page is displayed and redirected to Home page on authentication
  a.2) if user enters Login page URL then Login page is displayed and redirected to Home page on authentication
b) User is already authenticated in current browser session, a new tab is opened and
  b.1) if user enters Home page URL then it directly shows Home page (already authenticated)
  b.2) if user enters Login page URL then Login page is displayed -- this is the issue, it should either directly take user to Home page or invalidate the existing session and let user proceed with new.
How do I achieve this? Any help is highly appreciated.
Thanks,
Jai

Answer 1

Thanks Frank and everyone for your help.
I am able to achieve what Frank suggested using phase listener. We don't have a custom phase listener but I created one and instead of configuring at global level, just defined the ControllerClass in the pageDef of my login page.  
Code from afterPhase is:
    public void afterPhase(PagePhaseEvent pagePhaseEvent) {
        if (pagePhaseEvent.getPhaseId() == Lifecycle.INIT_CONTEXT_ID) {
            FacesContext fctx = FacesContext.getCurrentInstance();
            String viewRootId = fctx.getViewRoot().getViewId();
            if ("/pages/login.jspx".equalsIgnoreCase(viewRootId) &&
                ADFContext.getCurrent().getSecurityContext().isAuthenticated()) {
                try {
                    String homeViewId = "pages/home.jspx";
                    ControllerContext controllerCtx = null;
                    controllerCtx = ControllerContext.getInstance();
                    String activityURL =
                        controllerCtx.getGlobalViewActivityURL(homeViewId);
                    fctx.getExternalContext().redirect(activityURL);
                } catch (IOException ioe) {
                    _logger.logException(ioe);
My only concern here is that I am hardcoding the login and home page url. Is there a better way to implement this?
Thanks,
Jai