Grails: Split & bind comma separated string to List<String>

SkuProfilesController.groovy

class SkuProfilesController {

  def skuProfileService

  def show() {
    paramsSplit(['ids', 'fields'])
    def cmd = bindData(new ListSkuProfilesCommand(), params)
    if (!cmd.validate()) {
      throw new EntityValidationException(cmd.errors)
    }

    restpond skuProfileService.findAllSkuProfilesByVerticalAndFields(cmd)
  }

  private void paramsSplit(List<String> splitableParams) {
    splitableParams.each { splitableParam ->
      def commaSeparatedString = params[splitableParam]?.toString() ?: ''
      params[splitableParam] = commaSeparatedString.split(',').toList()
    }
  }
}

@Validateable
class ListSkuProfilesCommand {
  Long verticalId
  List<Long> ids
  List<String> fields

  static constraints = {
    verticalId nullable: false
    ids nullable: false, size: 1..20
  }
}

Worth to mention that validation are still enforced without problem