public function invoke()
 {
     if (isset($_POST['CheckCustomer'])) {
         $user = new User();
         $hospitalID = $user->getID();
         $customer = new Customer();
         $customerID = $customer->getIDByNationalNb();
         $customerName = $customer->getNameByNationalNb();
         $hospital = new Hospital();
         $myResult = $hospital->getOldServicesByCustomerNationalNb();
         $myResult1 = $hospital->getOldServicesByCustomerNationalNb();
         $oprView = new OperationView();
         if ($row = mysql_fetch_assoc($myResult)) {
             $oprView->showServices($myResult1, $hospitalID, $customerID, $customerName);
         } else {
             $myResult = $customer->getInfoByNationalNb();
             if ($row = mysql_fetch_assoc($myResult)) {
                 $oprView->showCustomerInfo($row, $hospitalID, $customerID, $customerName);
             } else {
                 $oprView->showUnavailable();
             }
         }
     }
 }