add(new Label("welcome", "Welcome Only logged in users can see this page"));
SecurePageLink<Void> securePageLink = new SecurePageLink<Void>("link", PageA.class);
add(securePageLink);
add(SecureComponentHelper.setSecurityCheck(new Label("sorry",
"you are not allowed to go to Page A"),
new InverseSecurityCheck(securePageLink.getSecurityCheck())));
}