Show Portlet if user is Logged In

If you want to show portlet only after user is login otherwise hide it.
Then use following code in your doView() method of a particular portlet.

ThemeDisplay themeDisplay= (ThemeDisplay)renderRequest.getAttribute(WebKeys.THEME_DISPLAY);
        if(!themeDisplay.isSignedIn()){
            renderRequest.setAttribute(WebKeys.PORTLET_CONFIGURATOR_VISIBILITY, Boolean.FALSE);
        }