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

java.lang.Object
  extended by org.apache.hadoop.mapreduce.lib.aggregate.LongValueSum
All Implemented Interfaces:
ValueAggregator<String>
Direct Known Subclasses:
LongValueSum

@InterfaceAudience.Public
@InterfaceStability.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
LongValueSum()
          the default constructor
 
Method Summary
 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 Detail

LongValueSum

public LongValueSum()
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 - 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.


Copyright © 2012 Apache Software Foundation. All Rights Reserved.