Package org.apache.hadoop.mapred.lib

Library of generally useful mappers, reducers, and partitioners.

See:
Description

Class Summary

FieldSelectionMapReduce	This class implements a mapper/reducer class that can be used to perform field selections in a manner similar to unix cut.
HashPartitioner	Partition keys by their Object.hashCode().
IdentityMapper	Implements the identity function, mapping inputs directly to outputs.
IdentityReducer	Performs no reduction, writing all input values directly to the output.
InverseMapper	A Mapper that swaps keys and values.
KeyFieldBasedPartitioner
LongSumReducer	A Reducer that sums long values.
MultithreadedMapRunner	Multithreaded implementation for @link org.apache.hadoop.mapred.MapRunnable.
NullOutputFormat	Consume all outputs and put them in /dev/null.
RegexMapper	A Mapper that extracts text matching a regular expression.
TokenCountMapper	A Mapper that maps text values into pairs.

Package org.apache.hadoop.mapred.lib Description

Library of generally useful mappers, reducers, and partitioners.