Grails: How to combine domain objects' errors with command objects' errors?

Question

Suppose I have User domain class and RegistrationCommand class. So when user is registering on website there are two steps for data validation:

1. RegistrationCommand constraints validation.
2. User domain object constrains validation.

Controller action receive command object and pass it to view in a model after computing. So, I want to join domain objects' validation errors with command objects' errors and pass them as a part of command object. What is the best way to do that?

Answer 1

I think the full answer is:

if (!user.validate() || !user.save(true))
{
    if (user.errors.hasErrors())
    {
        user.errors.allErrors.each {FieldError error ->
            final String field = error.field?.replace('profile.', '')
            final String code = "registrationCommand.$field.$error.code"
            command.errors.rejectValue(field, code)
        }
    }
    chain(action: 'registration', model: [command: command])
    return
}

Answer 2

I did the following for my project and found it to be more cleaner!

domain.errors.each {
  cmdObject.errors.reject(it.code, g.message(error: it))
} 

Answer 3

You could probably use the reject mechanism, i.e.

domainObjects.errors.each{
     commandObject.errors.reject( ... )
}

http://grails.org/doc/1.3.7/ref/Domain%20Classes/errors.html