org.apache.hadoop.mapred.lib.aggregate

Class DoubleValueSum

java.lang.Object

org.apache.hadoop.mapred.lib.aggregate.DoubleValueSum

All Implemented Interfaces:

ValueAggregator

public class DoubleValueSum
extends java.lang.Object
implements ValueAggregator

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

Constructor Summary

Constructors

Constructor and Description
DoubleValueSum() The default constructor

Method Summary

Methods

Modifier and Type	Method and Description
void	addNextValue(double val) add a value to the aggregator
void	addNextValue(java.lang.Object val) add a value to the aggregator
java.util.ArrayList<java.lang.String>	getCombinerOutput()
java.lang.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 Detail

DoubleValueSum

public DoubleValueSum()

The default constructor

Method Detail

addNextValue

public void addNextValue(java.lang.Object val)

add a value to the aggregator

Specified by:

addNextValue in interface ValueAggregator

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 java.lang.String getReport()

Specified by:

getReport in interface ValueAggregator

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

getCombinerOutput

public java.util.ArrayList<java.lang.String> getCombinerOutput()

Specified by:

getCombinerOutput in interface ValueAggregator

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.