public function updatePageItem($id_page)
 {
     try {
         $pageItemsModel = Payment_Model_DbTable_PageItems::getInstance();
         $pageItemsModel->updatePageItem($id_page, $this->getItemId(), time(), $this->getDefaultTime());
     } catch (Exception $ex) {
         throw $ex;
     }
 }
 public function isValid($id_page)
 {
     if (isset($this->_is_valid[$id_page])) {
         return $this->_is_valid[$id_page];
     }
     $pageItemsModel = Payment_Model_DbTable_PageItems::getInstance();
     $pageItem = $pageItemsModel->findByPageItem($id_page, self::CODE);
     $this->_is_valid[$id_page] = false;
     if (!empty($pageItem)) {
         if (intval($pageItem->time_expired) - time() > 0) {
             $this->_is_valid[$id_page] = true;
         }
     }
     return $this->_is_valid[$id_page];
 }