@Override public void merge(MeasureAggregator aggregator){
  AvgBigDecimalAggregator avgAggregator=(AvgBigDecimalAggregator)aggregator;
  if (!avgAggregator.isFirstTime()) {
    aggVal=aggVal.add(avgAggregator.aggVal);
    count+=avgAggregator.count;
    firstTime=false;
  }
}

@ Override public void merge ( MeasureAggregator aggregator ) { AvgBigDecimalAggregator avgAggregator = ( AvgBigDecimalAggregator ) aggregator ; if ( ! avgAggregator . isFirstTime ( ) ) { aggVal = aggVal . add ( avgAggregator . aggVal ) ; count += avgAggregator . count ; firstTime = false ; } }
this method merge the aggregated value , in average aggregator it will add count and aggregate value
