BatchSave.groovy

def updateCreateUserRoleGroups(User user, List<RoleGroup> roleGroupList) {
        if (!user || !roleGroupList) return []
        def currentSession = sessionFactory.getCurrentSession()

        def promiseMap = new PromiseMap()
        roleGroupList.each { roleGroup ->
            def exists = UserRoleGroup.exists(user.id as Long, roleGroup.id as Long)
            promiseMap["${roleGroup.displayName.trim().toUpperCase().replaceAll(~/\s/, "_")}"] = {
                if (!exists) {
                    UserRoleGroup.withNewTransaction { status ->
                        currentSession.save(new UserRoleGroup(user: user, roleGroup: roleGroup))
                    }
                }
            }
        }

        promiseMap.onError { def error ->
            log.error("error updating user role groups for user ${user?.id} , $error")
        }

        promiseMap.get()
    }