private XElement getJobDataMap(XNamespace ns, JobDataMap jobDataMap)
        {
            XElement map = new XElement(ns + "job-data-map");
            foreach (var key in jobDataMap.GetKeys())
            {
                map.Add(new XElement(ns + "entry"
                    , new XElement(ns + "key", key)
                    , new XElement(ns + "value", jobDataMap[key])
                    )
                );
            }

            return map;
        }