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

Class DoubleValueSum

java.lang.Object

org.apache.hadoop.mapreduce.lib.aggregate.DoubleValueSum

All Implemented Interfaces:

ValueAggregator<String>

Direct Known Subclasses:

DoubleValueSum

@Public
@Stable
public class DoubleValueSum
extends Object
implements ValueAggregator<String>

This class implements a value aggregator that sums up a sequence of double values.

Constructor Summary

Constructors

Constructor	Description
DoubleValueSum()	The default constructor

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Details

DoubleValueSum

public DoubleValueSum()

The default constructor

Method Details

addNextValue

public void addNextValue(Object val)

add a value to the aggregator

Specified by:

addNextValue in interface ValueAggregator<String>

Parameters:

val - an object whose string representation represents a double value.

addNextValue

public void addNextValue(double val)

add a value to the aggregator

Parameters:

val - a double value.

getReport

public String getReport()

Specified by:

getReport in interface ValueAggregator<String>

Returns:

the string representation of the aggregated value

getSum

public double getSum()

Returns:

the aggregated value

reset

public void reset()

reset the aggregator

Specified by:

reset in interface ValueAggregator<String>

getCombinerOutput

public ArrayList<String> getCombinerOutput()

Specified by:

getCombinerOutput in interface ValueAggregator<String>

Returns:

return an array of one element. The element is a string representation of the aggregated value. The return value is expected to be used by the a combiner.