Interface ParallelAggregator<I, E, O, ACC extends Accumulator<I,E,O>>

All Superinterfaces:

Aggregator<I,E,O>

All Known Implementing Classes:

AggCounting, AggErrorHandler, AggFromCollector, AggInputBroadcast, AggInputBroadcastMap, AggInputFilter, AggInputFlatMap, AggInputSplit, AggInputTransform, AggLcaMap, AggNatural, AggOutputTransform, AggReduce

public interface ParallelAggregator<I, E, O, ACC extends Accumulator<I,E,O>>
extends Aggregator<I,E,O>

Aggregator suitable for parallel processing. Extends Aggregator with a method to combine accumulators.

Author:

raven

Method Summary

Modifier and Type	Method	Description
default Collector<I,?,O>	asCollector()
default Collector<I,?,O>	asCollector(E env)	Wrap this aggregator as a Java8 collector.
ACC	combine(ACC a, ACC b)	Combine accumulators.
default ACC	combineRaw(Object x, Object y)	Combine method that works on Objects.
ACC	createAccumulator()

Methods inherited from interface Aggregator

accumulateAll, accumulateAll, accumulateAll, finish

Method Details

createAccumulator

ACC createAccumulator()

Specified by:

createAccumulator in interface Aggregator<I,E,O>

combine

ACC combine(ACC a,
 ACC b)

Combine accumulators. This method is allowed to mutate any of if its arguments, hence accumulators should be considered exhausted after combination.

Parameters:

a - First participant of combination

b - Second participant of combination

Returns:

Combined accumulator

combineRaw

default ACC combineRaw(Object x,
 Object y)

Combine method that works on Objects. Exact type signatures are typically too unwieldy to be carried around in user code. Delegates to combine(Accumulator, Accumulator) thus its notes apply.

Parameters:

x - First participant of combination

y - Second participant of combination

Returns:

Combined accumulator

asCollector

default Collector<I,?,O> asCollector()

asCollector

default Collector<I,?,O> asCollector(E env)

Wrap this aggregator as a Java8 collector.

Returns:

The collector view of this aggregator