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

Class LongValueSum

java.lang.Object

org.apache.hadoop.mapreduce.lib.aggregate.LongValueSum

All Implemented Interfaces:

ValueAggregator<String>

Direct Known Subclasses:

LongValueSum

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

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

Constructor Summary

Constructors

Constructor	Description
LongValueSum()	the default constructor

Method Summary

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

LongValueSum

public LongValueSum()

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 long value.

addNextValue

public void addNextValue(long val)

add a value to the aggregator

Parameters:

val - a long value.

getSum

public long getSum()

Returns:

the aggregated value

getReport

public String getReport()

Specified by:

getReport in interface ValueAggregator<String>

Returns:

the string representation of 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.