Package org.apache.hadoop.mapred.lib
package org.apache.hadoop.mapred.lib
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ClassDescriptionPartition
BinaryComparablekeys using a configurable part of the bytes array returned byBinaryComparable.getBytes().The ChainMapper class allows to use multiple Mapper classes within a single Map task.The ChainReducer class allows to chain multiple Mapper classes after a Reducer within the Reducer task.An abstractInputFormatthat returnsCombineFileSplit's inInputFormat.getSplits(JobConf, int)method.A generic RecordReader that can hand out different recordReaders for each chunk in aCombineFileSplit.A wrapper class for a record reader that handles a single file split.Input format that is aCombineFileInputFormat-equivalent forSequenceFileInputFormat.Input format that is aCombineFileInputFormat-equivalent forTextInputFormat.org.apache.hadoop.mapred.lib.DelegatingInputFormat<K,V> AnInputFormatthat delegates behaviour of paths to multiple other InputFormats.org.apache.hadoop.mapred.lib.DelegatingMapper<K1,V1, K2, V2> AnMapperthat delegates behaviour of paths to multiple other mappers.This class implements a mapper/reducer class that can be used to perform field selections in a manner similar to unix cut.FilterOutputFormat<K,V> FilterOutputFormat is a convenience class that wraps OutputFormat.org.apache.hadoop.mapred.lib.FilterOutputFormat.FilterRecordWriter<K,V> FilterRecordWriteris a convenience wrapper class that implementsRecordWriter.HashPartitioner<K2,V2> Partition keys by theirObject.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.InputSampler<K,V> org.apache.hadoop.mapred.lib.InputSampler.IntervalSampler<K,V> Sample from s splits at regular intervals.org.apache.hadoop.mapred.lib.InputSampler.RandomSampler<K,V> Sample from random points in the input.org.apache.hadoop.mapred.lib.InputSampler.Sampler<K,V> Interface to sample using anInputFormat.org.apache.hadoop.mapred.lib.InputSampler.SplitSampler<K,V> Samples the first n records from s splits.InverseMapper<K,V> AMapperthat swaps keys and values.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 seeKeyFieldBasedComparator.LazyOutputFormat<K,V> A Convenience class that creates output lazily.AReducerthat sums long values.This class supports MapReduce jobs that have multiple input paths with a differentInputFormatandMapperfor each pathMultipleOutputFormat<K,V> This abstract class extends the FileOutputFormat, allowing to write the output data to different output files.The MultipleOutputs class simplifies writing to additional outputs other than the job default output via theOutputCollectorpassed to themap()andreduce()methods of theMapperandReducerimplementations.This class extends the MultipleOutputFormat, allowing to write the output data to different output files in sequence file output format.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 forMapRunnable.NLineInputFormat which splits N lines of input as one split.NullOutputFormat<K,V> Consume all outputs and put them in /dev/null.RegexMapper<K>AMapperthat extracts text matching a regular expression.AMapperthat maps text values into <token,freq> pairs.Partitioner effecting a total order by reading split points from an externally generated source.