org.apache.hadoop.mapreduce.lib.aggregate

Class StringValueMin

java.lang.Object

org.apache.hadoop.mapreduce.lib.aggregate.StringValueMin

All Implemented Interfaces:

ValueAggregator<String>

Direct Known Subclasses:

StringValueMin

@InterfaceAudience.Public
@InterfaceStability.Stable
public class StringValueMin
extends Object
implements ValueAggregator<String>

This class implements a value aggregator that maintain the smallest of a sequence of strings.

Constructor Summary

Constructors

Constructor and Description
StringValueMin() the default constructor

Method Summary

Methods

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

StringValueMin

public StringValueMin()

the default constructor

Method Detail

addNextValue

public void addNextValue(Object val)

add a value to the aggregator

Specified by:

addNextValue in interface ValueAggregator<String>

Parameters:

val - a string.

getVal

public String getVal()

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.