code: @SuppressWarnings("rawtypes")
      public SortedMap<String, Gauge> getGauges(MetricFilter filter) {
          return getMetrics(Gauge.class, filter);
      }
docs: Returns a map of all the gauges in the registry and their names which match the given filter.
  
  @param filter the metric filter to match
  @return all the gauges in the registry