Applying Validation Constraints in Classes other than Domain classes and Command Objects

We usually specify validation constraints in domain classes and command objects.
But, if it is required to provide validation in other classes(like classes in src/groovy), we can do so in two ways :
1. Defining a static constraints property in the class and using the @validateable annotation.
2. Defining a static constraints propery in the class and making an entry of the class in grails.validateable.classes property in config.groovy.

Here is an example of first way:
[java]
package com.example.dto
import grails.validation.Validateable
@Validateable
class DataDTO {
String site
Integer views

static constraints = {
site blank: false
views blank: false
}
}
[/java]
If a class is not marked with @Validateable, it may still be made validateable by defining the static constraints property in the class (as shown above) and then assigning class name(with package name) to the grails.validateable.classes property in Config.groovy:

[java]
grails.validateable.classes = [com.example.dto.DataDTO]
[/java]

In older versions of grails, one could achieve the same result in a slightly different way as mentioned here.

Hope it helps 🙂

Raj Gupta
raj.gupta@intelligrape.com
@rajdgreat007