@Override
  public void accumulate(Object value) {
    if (value != null && value != QueryService.UNDEFINED) {
      super.accumulate(value);
      ++count;
    }
  }
The aggregator for computing average which is used on the bucket node for partitioned region
based
queries.
geode-core/src/main/java/org/apache/geode/cache/query/internal/aggregate/AvgBucketNode.java