Package org.apache.hadoop.mapred.lib

Library of generally useful mappers, reducers, and partitioners.

See:
          Description

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

Package org.apache.hadoop.mapred.lib Description

Library of generally useful mappers, reducers, and partitioners.



Copyright © 2006 The Apache Software Foundation