@Override
public boolean isSignedIn() {
if (userId < 1) {
IAuthenticationStrategy strategy = getAuthenticationStrategy();
// get username and password from persistence store
String[] data = strategy.load();
if ((data != null) && (data.length > 2)) {
// try to sign in the user
if (!signIn(data[0], data[1], data[2])) {
// the loaded credentials are wrong. erase them.
strategy.remove();