public List<MetricDisplaySummary> getMetrics(
      Resource parentResource,
      AutoGroupComposite resourceGroupComposite,
      Subject subject,
      long beginTime,
      long endTime)
      throws MeasurementException {
    if (log.isTraceEnabled()) {
      log.trace(
          "finding metric summaries for resourceType ["
              + resourceGroupComposite.getResourceType().getName());
    }

    List<MetricDisplaySummary> metricSummaries = null;
    // TODO GH: Why are we only getting the first one? --> single resource case
    //

    List resources = resourceGroupComposite.getResources();
    if ((resources != null) && (resources.size() == 1)) {
      ResourceWithAvailability resource = (ResourceWithAvailability) resources.get(0);

      metricSummaries =
          chartsManager.getMetricDisplaySummariesForMetrics(
              subject,
              resource.getResource().getId(),
              DataType.MEASUREMENT,
              beginTime,
              endTime,
              true,
              true);
    } else if ((resources != null) && (resources.size() > 1)) {
      List<Resource> res = new ArrayList<Resource>();
      for (Object o : resources) {
        if (o instanceof ResourceWithAvailability) {
          ResourceWithAvailability rwa = (ResourceWithAvailability) o;
          res.add(rwa.getResource());
        }
      }

      Map<Integer, List<MetricDisplaySummary>> sumMap =
          dataManager.findNarrowedMetricDisplaySummariesForCompatibleResources(
              subject, res, beginTime, endTime);
      metricSummaries = sumMap.values().iterator().next();

      // fill in some data that does not come from the backend
      for (MetricDisplaySummary tmp : metricSummaries) {
        tmp.setParentId(parentResource.getId());
        tmp.setChildTypeId(resourceGroupComposite.getResourceType().getId());
      }
    }

    return metricSummaries;
  }
  @SuppressWarnings("unchecked")
  @Override
  public ActionForward execute(
      ComponentContext context,
      ActionMapping mapping,
      ActionForm form,
      HttpServletRequest request,
      HttpServletResponse response)
      throws Exception {

    dataManager = LookupUtil.getMeasurementDataManager();
    chartsManager = LookupUtil.getMeasurementChartsManager();

    WebUser user = SessionUtils.getWebUser(request.getSession());
    Subject subject = user.getSubject();
    Resource resource = (Resource) request.getAttribute(AttrConstants.RESOURCE_ATTR);

    // Get metric time range
    MeasurementPreferences preferences = user.getMeasurementPreferences();
    MetricRangePreferences rangePreferences = preferences.getMetricRangePreferences();
    long begin = rangePreferences.begin;
    long end = rangePreferences.end;

    List<AutoGroupComposite> children;
    List<AutoGroupCompositeDisplaySummary> displaySummary;
    int parentId = -1;
    int resourceTypeId = -1;
    if (resource == null) {
      parentId =
          WebUtility.getOptionalIntRequestParameter(
              request, AttrConstants.AUTOGROUP_PARENT_ATTR, -1);
      if (parentId > 0) // get data for individual autogroup children
      {
        resourceTypeId =
            WebUtility.getOptionalIntRequestParameter(
                request, AttrConstants.AUTOGROUP_TYPE_ATTR, -1);
        children = getAutoGroupChildren(subject, parentId, resourceTypeId);
        if (children == null) children = new ArrayList<AutoGroupComposite>();
        displaySummary = new ArrayList<AutoGroupCompositeDisplaySummary>(children.size() + 1);

        // get the parent
        ResourceManagerLocal resourceManager = LookupUtil.getResourceManager();
        AutoGroupComposite parentComposite =
            resourceManager.getResourceAutoGroup(subject, parentId);
        if (parentComposite != null) {
          parentComposite.setMainResource(true);
          List<MetricDisplaySummary> metricSummaries = null;
          metricSummaries =
              chartsManager.getMetricDisplaySummariesForMetrics(
                  subject, parentId, DataType.MEASUREMENT, begin, end, true, true);
          displaySummary.add(
              0, new AutoGroupCompositeDisplaySummary(parentComposite, metricSummaries));
        }
        /* We have n children with each child representing exactly 1 resource.
         * As we are in an autogroup, all children have the same type, so we can just feed them to the backend
         * in one call with all n resources.
         */

        // Loop over children, get resources, call some ..forMultiMetrics..
        List<Integer> resourceIds = new ArrayList<Integer>();
        for (AutoGroupComposite child : children) {
          List resources = child.getResources();
          ResourceWithAvailability rwa = (ResourceWithAvailability) resources.get(0);
          resourceIds.add(rwa.getResource().getId());
        }

        // Map<ResourceId, List<Summaries for that resource>
        Map<Integer, List<MetricDisplaySummary>> summaries =
            dataManager.findNarrowedMetricDisplaySummariesForResourcesAndParent(
                subject, resourceTypeId, parentId, resourceIds, begin, end);
        for (AutoGroupComposite child : children) {
          if (parentComposite != null) child.increaseDepth(1);

          List resources = child.getResources();
          ResourceWithAvailability rwa = (ResourceWithAvailability) resources.get(0);
          List<MetricDisplaySummary> sumList = summaries.get(rwa.getResource().getId());
          displaySummary.add(new AutoGroupCompositeDisplaySummary(child, sumList));
        }

      } else {
        RequestUtils.setError(request, MessageConstants.ERR_RESOURCE_NOT_FOUND);
        return null;
      }
    } else { // resource != null
      // get children of that single resource, which can be individual resources or autogroups
      children = getResourceChildren(resource, subject);

      displaySummary = new ArrayList<AutoGroupCompositeDisplaySummary>(children.size());
      for (AutoGroupComposite child : children) {
        List<MetricDisplaySummary> metrics = getMetrics(resource, child, subject, begin, end);

        displaySummary.add(new AutoGroupCompositeDisplaySummary(child, metrics));
      }
    }

    context.putAttribute(AttrConstants.CTX_SUMMARIES, displaySummary);

    return null;
  }