/**
  * Display the "device group detail" page.
  *
  * @param groupToken
  * @param request
  * @return
  */
 @RequestMapping("/groups/{groupToken}")
 public ModelAndView deviceGroupDetail(
     @PathVariable("groupToken") String groupToken, HttpServletRequest request) {
   Tracer.start(TracerCategory.AdminUserInterface, "deviceGroupDetail", LOGGER);
   try {
     Map<String, Object> data = createBaseData(request);
     ITenant tenant = (ITenant) data.get(DATA_TENANT);
     IDeviceManagement management = SiteWhere.getServer().getDeviceManagement(tenant);
     IDeviceGroup group = management.getDeviceGroup(groupToken);
     if (group != null) {
       data.put("group", group);
       return new ModelAndView("groups/detail", data);
     }
     return showError("Device group for token '" + groupToken + "' not found.");
   } catch (NoTenantException e) {
     return showTenantChoices(getUrl(request), request);
   } catch (SiteWhereException e) {
     return showError(e);
   } finally {
     Tracer.stop(LOGGER);
   }
 }