org.apache.hadoop.mapred.lib
Class LongSumReducer
java.lang.Object
org.apache.hadoop.mapred.MapReduceBase
org.apache.hadoop.mapred.lib.LongSumReducer
- All Implemented Interfaces:
- Closeable, JobConfigurable, Reducer
public class LongSumReducer
- extends MapReduceBase
- implements Reducer
A Reducer
that sums long values.
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
LongSumReducer
public LongSumReducer()
reduce
public void reduce(WritableComparable key,
Iterator values,
OutputCollector output,
Reporter reporter)
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 keyvalues
- the values to combineoutput
- to collect combined values
- Throws:
IOException
Copyright © 2006 The Apache Software Foundation