class Application_Model_User
{
    const AUTHENTICATION_FIELD = 'name';
    protected static $_authenticated;

    public static function getAuthenticated ()
    {
        if (self::$_authenticated === null) {
            self::$_authenticated = new self;
            $auth = Zend_Auth::getInstance();

            if ($auth->hasIdentity()) {
                self::$_authenticated = self::$_authenticated->getTable()->findOneBy(self::AUTHENTICATION_FIELD, $auth->getIdentity());
            }
        }

        return self::$_authenticated;
    }
}