@Transactional
class RegisterService {

   def saltSource
   def springSecurityUiService
   def grailsApplication
   def changePassword(RegistrationCode registrationCode, String password) {

      String salt = saltSource instanceof NullSaltSource ? null : registrationCode.username

      RegistrationCode.withTransaction { status ->
         String usernameFieldName = SpringSecurityUtils.securityConfig.userLookup.usernamePropertyName
         def user = User.findWhere((usernameFieldName): registrationCode.username)
         user.password = springSecurityUiService.encodePassword(password, salt)
         user.save()
         registrationCode.delete()
      }
   }
}