Package org.apache.hadoop.mapred.lib

Library of generally useful mappers, reducers, and partitioners.

See:
Description

Class Summary

FieldSelectionMapReduce<K extends WritableComparable,V extends Writable>	This class implements a mapper/reducer class that can be used to perform field selections in a manner similar to unix cut.
HashPartitioner<K2 extends WritableComparable,V2 extends Writable>	Partition keys by their Object.hashCode().
IdentityMapper<K extends WritableComparable,V extends Writable>	Implements the identity function, mapping inputs directly to outputs.
IdentityReducer<K extends WritableComparable,V extends Writable>	Performs no reduction, writing all input values directly to the output.
InverseMapper<K extends WritableComparable,V extends WritableComparable>	A Mapper that swaps keys and values.
KeyFieldBasedPartitioner<K2 extends WritableComparable,V2 extends Writable>
LongSumReducer<K extends WritableComparable>	A Reducer that sums long values.
MultithreadedMapRunner<K1 extends WritableComparable,V1 extends Writable,K2 extends WritableComparable,V2 extends Writable>	Multithreaded implementation for @link org.apache.hadoop.mapred.MapRunnable.
NullOutputFormat<K extends WritableComparable,V extends Writable>	Consume all outputs and put them in /dev/null.
RegexMapper<K extends WritableComparable>	A Mapper that extracts text matching a regular expression.
TokenCountMapper<K extends WritableComparable>	A Mapper that maps text values into pairs.

Package org.apache.hadoop.mapred.lib Description

Library of generally useful mappers, reducers, and partitioners.