Grails command object data binding

Question

Grails has very good support for binding request parameters to a domain object and it\'s associations. This largely relies on detecting request parameters that end with

Answer 1

Command Object in Grails

In Grails, command objects are like domain classes, but don’t persist data. Using command objects in Grails is a simple way to perform data binding and validation when there is no need to create domain object.

First thing you‘ll need to do is describe your command object. It is fine to do in the same file that contains controller that will use it. If command object will be used by more than one controller, describe it in groovy source directory.

Declaring Command Objects

@Validateable
class UserProfileInfoCO {
    String name
    String addressLine1
    String addressLine2
    String city
    String state
    String zip
    String contactNo

    static constraints = {
        name(nullable: false, blank: false)
        addressLine1(nullable: true, blank: true)
        addressLine2(nullable: true, blank: true)
        city(nullable: true, blank: true)
        state(nullable: true, blank: true)
        zip(nullable: true, blank: true, maxSize: 6, matches: "[0-9]+")
        contactNo(blank: true, nullable: true)
    }
}

Using Command Objects

Next thing you’ll probably want to do is bind the data, that is being received by action in your controller to the command object and validate it.

 def updateUserProfile(UserProfileInfoCO userProfileInfo) {     
  // data binding and validation
   if (!userProfileInfo.hasErrors()) {
      //do something
   } 

}