org.apache.hadoop.mapred.lib.aggregate

接口 ValueAggregator

所有已知实现类:

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

public interface ValueAggregator

This interface defines the minimal protocol for value aggregators.

方法概要

方法

限定符和类型	方法和说明
void	addNextValue(Object val) add a value to the aggregator
ArrayList	getCombinerOutput()
String	getReport()
void	reset() reset the aggregator

方法详细资料

addNextValue

void addNextValue(Object val)

add a value to the aggregator

参数:

val - the value to be added

reset

void reset()

reset the aggregator

getReport

String getReport()

返回:

the string representation of the agregator

getCombinerOutput

ArrayList getCombinerOutput()

返回:

an array of values as the outputs of the combiner.