Package org.apache.hadoop.mapreduce.lib.aggregate

Interface ValueAggregator<E>

All Known Subinterfaces:

ValueAggregator<E>

All Known Implementing Classes:

DoubleValueSum, DoubleValueSum, LongValueMax, LongValueMax, LongValueMin, LongValueMin, LongValueSum, LongValueSum, StringValueMax, StringValueMax, StringValueMin, StringValueMin, UniqValueCount, UniqValueCount, ValueHistogram, ValueHistogram

@Public
@Stable
public interface ValueAggregator<E>

This interface defines the minimal protocol for value aggregators.

Method Summary

Modifier and Type	Method	Description
void	addNextValue(Object val)	add a value to the aggregator
ArrayList<E>	getCombinerOutput()
String	getReport()
void	reset()	reset the aggregator

Method Details

addNextValue

void addNextValue(Object val)

add a value to the aggregator

Parameters:

val - the value to be added

reset

void reset()

reset the aggregator

getReport

String getReport()

Returns:

the string representation of the agregator

getCombinerOutput

ArrayList<E> getCombinerOutput()

Returns:

an array of values as the outputs of the combiner.