Data-Centric Applications with Vaadin 8

Keeping track of authenticated users

Following this approach, we can store the username in the HTTP session when a user is successfully authenticated. We can also check whether the user has been authenticated by checking whether a value exists in the HTTP session. This can be implemented as follows:

public class AuthService {

    private static final String USERNAME_ATTRIBUTE = "username";

    public static boolean authenticate(
            String username, String password) {

        boolean authentic = "admin".equals(username) &&
                "admin".equals(password);
 
        if (authentic) {
            VaadinSession.getCurrent().setAttribute(
                    USERNAME_ATTRIBUTE, username);
        }

        return authentic;
    }

    public static boolean isAuthenticated() {
        return VaadinSession.getCurrent().getAttribute( USERNAME_ATTRIBUTE) ...