org.apache.nutch.mapReduce.lib
Class LongSumReducer

java.lang.Object
  org.apache.nutch.mapReduce.lib.LongSumReducer

All Implemented Interfaces:

Configurable, Reducer

public class LongSumReducer

extends Object

implements Reducer

A Reducer that sums long values.

Constructor Summary

LongSumReducer()

Method Summary

void	configure(JobConf job) Initializes a new instance from a JobConf.
void	reduce(WritableComparable key, Iterator values, OutputCollector output) Combines values for a given key.

Methods inherited from class java.lang.Object

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

Constructor Detail

LongSumReducer

public LongSumReducer()

Method Detail

configure

public void configure(JobConf job)

Description copied from interface: Configurable

Initializes a new instance from a JobConf.

Specified by:

configure in interface Configurable

Parameters:

job - the configuration

reduce

public void reduce(WritableComparable key,
                   Iterator values,
                   OutputCollector output)
            throws IOException

Description copied from interface: Reducer

Combines values for a given key. Output values must be of the same type as input values. Input keys must not be altered. Typically all values are combined into zero or one value. Output pairs are collected with calls to OutputCollector.collect(WritableComparable,Writable).

Specified by:

reduce in interface Reducer

Parameters:

key - the key

values - the values to combine

output - to collect combined values

Throws:

IOException