@Override
  public List<Record> getRecords(ClusterMetrics clusterMetrics,
    List<RecordFilter> pushDownFilters) {
    // Get records from RegionModeStrategy and add REGION_COUNT field
    List<Record> records = regionModeStrategy.selectModeFieldsAndAddCountField(fieldInfos,
      regionModeStrategy.getRecords(clusterMetrics, pushDownFilters), Field.REGION_COUNT);

    // Aggregation by NAMESPACE field
    return ModeStrategyUtils.aggregateRecords(records, Field.NAMESPACE);
  }
Implementation for {@link ModeStrategy} for Namespace Mode.
hbase-hbtop/src/main/java/org/apache/hadoop/hbase/hbtop/mode/NamespaceModeStrategy.java