Package org.apache.hadoop.mapred.lib

Library of generally useful mappers, reducers, and partitioners.

See:
Description

Interface Summary

InputSampler.Sampler<K,V>

Interface to sample using an InputFormat.

Class Summary

ChainMapper	The ChainMapper class allows to use multiple Mapper classes within a single Map task.
ChainReducer	The ChainReducer class allows to chain multiple Mapper classes after a Reducer within the Reducer task.
CombineFileInputFormat<K,V>	An abstract InputFormat that returns CombineFileSplit's in InputFormat.getSplits(JobConf, int) method.
CombineFileRecordReader<K,V>	A generic RecordReader that can hand out different recordReaders for each chunk in a CombineFileSplit.
CombineFileSplit	A sub-collection of input files.
DelegatingInputFormat<K,V>	An InputFormat that delegates behaviour of paths to multiple other InputFormats.
DelegatingMapper<K1,V1,K2,V2>	An Mapper that delegates behaviour of paths to multiple other mappers.
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>	Deprecated. Use HashPartitioner instead.
IdentityMapper<K,V>	Deprecated. Use Mapper instead.
IdentityReducer<K,V>	Deprecated. Use Reducer instead.
InputSampler<K,V>	Utility for collecting samples and writing a partition file for TotalOrderPartitioner.
InputSampler.IntervalSampler<K,V>	Sample from s splits at regular intervals.
InputSampler.RandomSampler<K,V>	Sample from random points in the input.
InputSampler.SplitSampler<K,V>	Samples the first n records from s splits.
InverseMapper<K,V>	Deprecated. Use InverseMapper instead.
KeyFieldBasedComparator<K,V>	This comparator implementation provides a subset of the features provided by the Unix/GNU Sort.
KeyFieldBasedPartitioner<K2,V2>	Defines a way to partition keys based on certain key fields (also see KeyFieldBasedComparator.
LongSumReducer<K>	Deprecated. Use LongSumReducer instead.
MultipleInputs	This class supports MapReduce jobs that have multiple input paths with a different InputFormat and Mapper for each path
MultipleOutputFormat<K,V>	This abstract class extends the FileOutputFormat, allowing to write the output data to different output files.
MultipleOutputs	The MultipleOutputs class simplifies writting to additional outputs other than the job default output via the OutputCollector passed to the map() and reduce() methods of the Mapper and Reducer implementations.
MultipleSequenceFileOutputFormat<K,V>	This class extends the MultipleOutputFormat, allowing to write the output data to different output files in sequence file output format.
MultipleTextOutputFormat<K,V>	This class extends the MultipleOutputFormat, allowing to write the output data to different output files in Text output format.
MultithreadedMapRunner<K1,V1,K2,V2>	Multithreaded implementation for @link org.apache.hadoop.mapred.MapRunnable.
NLineInputFormat	NLineInputFormat which splits N lines of input as one split.
NullOutputFormat<K,V>	Deprecated. Use NullOutputFormat instead.
RegexMapper<K>	A Mapper that extracts text matching a regular expression.
TokenCountMapper<K>	Deprecated. Use TokenCounterMapper instead.
TotalOrderPartitioner<K extends WritableComparable,V>	Partitioner effecting a total order by reading split points from an externally generated source.

Package org.apache.hadoop.mapred.lib Description

Library of generally useful mappers, reducers, and partitioners.