code: public boolean isSet(_Fields field) {
      if (field == null) {
        throw new IllegalArgumentException();
      }
  
      switch (field) {
      case METRIC_ID:
        return is_set_metricId();
      case TS:
        return is_set_ts();
      case METRIC_TYPE:
        return is_set_metricType();
      case LONG_VALUE:
        return is_set_longValue();
      case DOUBLE_VALUE:
        return is_set_doubleValue();
      case M1:
        return is_set_m1();
      case M5:
        return is_set_m5();
      case M15:
        return is_set_m15();
      case MEAN:
        return is_set_mean();
      case MIN:
        return is_set_min();
      case MAX:
        return is_set_max();
      case P50:
        return is_set_p50();
      case P75:
        return is_set_p75();
      case P95:
        return is_set_p95();
      case P98:
        return is_set_p98();
      case P99:
        return is_set_p99();
      case P999:
        return is_set_p999();
      case STDDEV:
        return is_set_stddev();
      case POINTS:
        return is_set_points();
      case POINT_SIZE:
        return is_set_pointSize();
      }
      throw new IllegalStateException();
    }
docs: Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise