public function isLogged()
    {
        $this->byPassIsLogged = true;
        try {
            // Is a session mechanism available?
            if (!session_id()) {
                if ($this->sessionManager) {
                    $this->sessionManager->start();
                } else {
                    throw new MoufException("The session must be initialized before checking if the user is logged. Please use session_start().");
                }
            }
            
            if (isset($_SESSION[$this->sessionPrefix.'MoufUserId'])) {
                return true;
            } else {
                foreach ($this->authProviders as $provider) {
                    /* @var $provider AuthenticationProviderInterface */
                    if ($provider->isLogged($this)) {
                        return true;
                    }
                }
            }
        } catch (\Exception $e) {
            $this->byPassIsLogged = false;
            throw $e;
        }
        $this->byPassIsLogged = false;
        return false;
    }