public static function isGuest()
 {
     if (!self::$_usr) {
         self::$_usr = FrontuserHelper::getLoginUser();
     }
     if (self::$_usr) {
         return false;
     } else {
         return true;
     }
 }
 /**
  * Logs out the current user and redirect to homepage.
  */
 public function actionLogout()
 {
     FrontuserHelper::logout();
     $this->redirect(Yii::app()->homeUrl);
 }
 public function login()
 {
     return FrontuserHelper::login($this->username, $this->password);
 }