How to use

rollingAggregate

method

in

com.hazelcast.jet.pipeline.StreamStageWithKey

@Nonnull @Override
public <R> StreamStage<R> rollingAggregate(@Nonnull AggregateOperation1<? super T, ?, ? extends R> aggrOp) {
  return groupingKey(constantKey()).rollingAggregate(aggrOp, (k, v) -> v);
}

private static Pipeline buildPipeline() {
  Pipeline p = Pipeline.create();
  p.drawFrom(Sources.<Entry<String, Integer>, Integer, Entry<String, Integer>>mapJournal(TRADES_MAP_NAME,
      DistributedPredicate.alwaysTrue(), EventJournalMapEvent::getNewValue, START_FROM_CURRENT))
   .groupingKey(Entry::getKey)
   .rollingAggregate(summingLong(Entry::getValue))
   .drainTo(Sinks.map(VOLUME_MAP_NAME));
  return p;
}

private static Pipeline buildPipeline() {
  Pipeline p = Pipeline.create();
  p.drawFrom(Sources.<Trade, Integer, Trade>mapJournal(TRADES_MAP_NAME,
      DistributedPredicate.alwaysTrue(), EventJournalMapEvent::getNewValue, START_FROM_CURRENT))
   .groupingKey(Trade::getTicker)
   .rollingAggregate(summingLong(Trade::getPrice))
   .drainTo(Sinks.map(VOLUME_MAP_NAME));
  return p;
}