Class AggReduce<I,E>

java.lang.Object

org.aksw.commons.collector.core.AggReduce<I,E>

All Implemented Interfaces:

Serializable, Aggregator<I,E,I>, ParallelAggregator<I, E, I, Accumulator<I,E,I>>

public class AggReduce<I,E>
extends Object
implements ParallelAggregator<I, E, I, Accumulator<I,E,I>>, Serializable

Aggregator whose accumulators apply a reduce operation to their value and their input to compute their new value. Accumulators are initialized with a zero element. Each accumulator obtains its zero element from a supplier which allows for reduce operations that mutate that element. Used as a basis for: min, max, sum (which in turn are the basis for e.g. avg)

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	AggReduce.AccReduceImpl

Field Summary

Fields

Modifier and Type	Field	Description
protected BinaryOperator<I>	plusOperator
protected Supplier<I>	zeroElementSupplier

Constructor Summary

Constructors

Constructor	Description
AggReduce(Supplier<I> zeroElementSupplier, BinaryOperator<I> plusOperator)

Method Summary

Modifier and Type	Method	Description
Accumulator<I,E,I>	combine(Accumulator<I,E,I> a, Accumulator<I,E,I> b)	Combine accumulators.
Accumulator<I,E,I>	createAccumulator()
boolean	equals(Object obj)
int	hashCode()

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Aggregator

accumulateAll, accumulateAll, accumulateAll, finish

Methods inherited from interface ParallelAggregator

asCollector, asCollector, combineRaw

Field Details

zeroElementSupplier

protected Supplier<I> zeroElementSupplier

plusOperator

protected BinaryOperator<I> plusOperator

Constructor Details

AggReduce

public AggReduce(Supplier<I> zeroElementSupplier,
 BinaryOperator<I> plusOperator)

Method Details

createAccumulator

public Accumulator<I,E,I> createAccumulator()

Specified by:

createAccumulator in interface Aggregator<I,E,I>

Specified by:

createAccumulator in interface ParallelAggregator<I, E, I, Accumulator<I,E,I>>

combine

public Accumulator<I,E,I> combine(Accumulator<I,E,I> a,
 Accumulator<I,E,I> b)

Description copied from interface: ParallelAggregator

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

Specified by:

combine in interface ParallelAggregator<I, E, I, Accumulator<I,E,I>>

Parameters:

a - First participant of combination

b - Second participant of combination

Returns:

Combined accumulator

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object