code: private List<Long> collectLongMetric(String metricGetterName) {
          List<Long> vals = new ArrayList<Long>();
          for(BdbEnvironmentStats envStats: environmentStatsTracked) {
              vals.add((Long) ReflectUtils.callMethod(envStats,
                                                      BdbEnvironmentStats.class,
                                                      metricGetterName,
                                                      new Class<?>[0],
                                                      new Object[0]));
          }
          return vals;
      }
docs: Calls the provided metric getter on all the tracked environments and
  obtains their values
  
  @param metricGetterName
  @return