No se pudo serializar la ejecución del flujo

Question

Excepción:

Error 500: Could not serialize flow execution; make sure all objects stored in 
           flow or flash scope are serializable
Servlet: grails
URI: /payment.com/grails/payment/makePayment.dispatch
Exception Message: payment.com.ValidationService$$EnhancerByCGLIB$$d0f2434f 
Caused by: Could not serialize flow execution; make sure all objects stored in 
           flow or flash scope are serializable 
Class: Unknown 
At Line: [-1] 
Code Snippet:

Discusión:

payment.com: project name         
payment: is the name of (domain, view, controller)
makePayment: is a webflow to make payment
ValidationService: is a service to test if credit card is valid or not

Problema:
Recibí este error en mi proyecto Grails

i have a grails webflow that makes a payment, in this webflow i use grails 
command object to validate input values.
when i call the method isValid from Validation service i got this error

Nota:

i try to serialize domain class, controller, service, & command object class, 
but i couldn't solve this issue.

cualquier ayuda, gracias

Editar:

Servicio de Validación

 package payment.com

 import java.io.Serializable;

 class ValidationService implements Serializable{

// Filter out non-digit characters
def getDigitsOnly (String s) {
  StringBuffer digitsOnly = new StringBuffer ();
  char c;
  for (int i = 0; i < s.length (); i++) {
    c = s.charAt (i);
    if (Character.isDigit (c)) digitsOnly.append (c);
  }
  return digitsOnly.toString ();
}

// Perform Luhn check
def isValid (String cardNumber) {
  String digitsOnly = getDigitsOnly (cardNumber);
  int sum = 0;
  int digit = 0;
  int addend = 0;
  boolean timesTwo = false;

  for (int i = digitsOnly.length () - 1; i >= 0; i--) {
    digit = Integer.parseInt (digitsOnly.substring (i, i + 1));
    if (timesTwo){
      addend = digit * 2;
      if (addend > 9) addend -= 9;
    }else{
      addend = digit;
    }
    sum += addend;
    timesTwo = !timesTwo;
  }
  int modulus = sum % 10;

  if (modulus == 0){
      return true
  }else{
    return false
  }
}
}

RealizarPagoPaso1Comando

package payment.com

import org.codehaus.groovy.grails.validation.Validateable;
import java.io.Serializable;
import payment.com.ValidationService;

@Validateable
class MakePaymentStep1Command implements Serializable{
ValidationService ValidationService
String cardNumber

static constraints ={
    cardNumber(blank:false, size:11..16, validator:{ val, obj->
        if (!obj.ValidationService.isValid(val)){
            return ['payment.cardNumber.invalid']
        }
        return true;
    })
}
 }

Controlador de pagos

class PaymentController{
....
....
def MakePaymentFlow = {
....
    Step1{
        on('submit').to('Step1Submit')
    }
    Step1Submit{
        action {MakePaymentStep1Command cmd ->
            flow.step1Bean = cmd
            if (!flow.step1Bean.validate()){
                error()
            }
        }
        on('error').to('Step1')
        on('success'){
            flow.message = null
        }.to('Step2')
    }


....
}


}

El error ocurre aquí:

 if (!flow.step1Bean.validate()){
     error()
 }

Answer 1

tiene un directorio (src/groovy) en su grails project.ponga su validation Service class en este directorio, y su makepaymentStepCommand será como:

MakePaymentStep1Command

package payment.com

import java.io.Serializable;
import payment.com.Validation;

class MakePaymentStep1Command implements Serializable{
Validation validation
String cardNumber

static constraints ={
    cardNumber(blank:false, size:11..16, validator:{ val, obj->
         if (!obj.validation.isValid(val)){
            return ['payment.cardNumber.invalid']
         }
         return true;
    })
}
}

I am not sure if this works, but try it.

Answer 2

Mirando el mensaje de excepción, parece ValidationService no es serializable (aunque no ha mostrado ningún código, por lo que es muy difícil adivinar qué podría estar pasando).

Supongo que diría que este objeto se inyecta de dependencia en cada Payment, y estás intentando almacenar un Payment en el alcance del flujo, lo que por lo tanto provoca un intento de almacenar también un PaymentService.