code: public static <T extends HistogramDataPoint> Map<String, T> generateHistogramSkeleton(HistogramBean<T> rval, DateTime from, DateTime to,
              HistogramIntervalType interval, Class<T> dataType) {
          return generateHistogramSkeleton(rval, from, to, interval, dataType, String.class);
      }
docs: Shortcut for the label (string) based histogram index.
  @param rval
  @param from
  @param to
  @param interval
  @param dataType