@Override
protected <AggInputT, AggOutputT> Aggregator<AggInputT, AggOutputT> createAggregatorInternal(
String name, Combine.CombineFn<AggInputT, ?, AggOutputT> combiner) {
Accumulator acc = getRuntimeContext().getAccumulator(name);
if (acc != null) {
AccumulatorHelper.compareAccumulatorTypes(
name, SerializableFnAggregatorWrapper.class, acc.getClass());
return (Aggregator<AggInputT, AggOutputT>) acc;
}
SerializableFnAggregatorWrapper<AggInputT, AggOutputT> accumulator =
new SerializableFnAggregatorWrapper<>(combiner);
getRuntimeContext().addAccumulator(name, accumulator);
return accumulator;
}
