org.apache.hadoop.mapred.lib
Class CombineFileInputFormat<K,V>

java.lang.Object
  org.apache.hadoop.mapred.FileInputFormat<K,V>
      org.apache.hadoop.mapred.lib.CombineFileInputFormat<K,V>

All Implemented Interfaces:

InputFormat<K,V>

public abstract class CombineFileInputFormat<K,V>
extends FileInputFormat<K,V>

An abstract InputFormat that returns CombineFileSplit's in InputFormat.getSplits(JobConf, int) method. Splits are constructed from the files under the input paths. A split cannot have files from different pools. Each split returned may contain blocks from different files. If a maxSplitSize is specified, then blocks on the same node are combined to form a single split. Blocks that are left over are then combined with other blocks in the same rack. If maxSplitSize is not specified, then blocks from the same rack are combined in a single split; no attempt is made to create node-local splits. If the maxSplitSize is equal to the block size, then this class is similar to the default spliting behaviour in Hadoop: each block is a locally processed split. Subclasses implement InputFormat.getRecordReader(InputSplit, JobConf, Reporter) to construct RecordReader's for CombineFileSplit's.

See Also:

CombineFileSplit

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapred.FileInputFormat

FileInputFormat.Counter

Field Summary

Fields inherited from class org.apache.hadoop.mapred.FileInputFormat

LOG

Constructor Summary

CombineFileInputFormat()
default constructor

Method Summary

protected void	createPool(JobConf conf, List<PathFilter> filters) Create a new pool and add the filters to it.
protected void	createPool(JobConf conf, PathFilter... filters) Create a new pool and add the filters to it.
abstract RecordReader<K,V>	getRecordReader(InputSplit split, JobConf job, Reporter reporter) This is not implemented yet.
InputSplit[]	getSplits(JobConf job, int numSplits) Splits files returned by FileInputFormat.listStatus(JobConf) when they're too big.
protected void	setMaxSplitSize(long maxSplitSize) Specify the maximum size (in bytes) of each split.
protected void	setMinSplitSizeNode(long minSplitSizeNode) Specify the minimum size (in bytes) of each split per node.
protected void	setMinSplitSizeRack(long minSplitSizeRack) Specify the minimum size (in bytes) of each split per rack.

Methods inherited from class org.apache.hadoop.mapred.FileInputFormat

addInputPath, addInputPaths, computeSplitSize, getBlockIndex, getInputPathFilter, getInputPaths, getSplitHosts, isSplitable, listStatus, setInputPathFilter, setInputPaths, setInputPaths, setMinSplitSize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CombineFileInputFormat

public CombineFileInputFormat()

default constructor

Method Detail

setMaxSplitSize

protected void setMaxSplitSize(long maxSplitSize)

Specify the maximum size (in bytes) of each split. Each split is approximately equal to the specified size.

setMinSplitSizeNode

protected void setMinSplitSizeNode(long minSplitSizeNode)

Specify the minimum size (in bytes) of each split per node. This applies to data that is left over after combining data on a single node into splits that are of maximum size specified by maxSplitSize. This leftover data will be combined into its own split if its size exceeds minSplitSizeNode.

setMinSplitSizeRack

protected void setMinSplitSizeRack(long minSplitSizeRack)

Specify the minimum size (in bytes) of each split per rack. This applies to data that is left over after combining data on a single rack into splits that are of maximum size specified by maxSplitSize. This leftover data will be combined into its own split if its size exceeds minSplitSizeRack.

createPool

protected void createPool(JobConf conf,
                          List<PathFilter> filters)

Create a new pool and add the filters to it. A split cannot have files from different pools.

createPool

protected void createPool(JobConf conf,
                          PathFilter... filters)

Create a new pool and add the filters to it. A pathname can satisfy any one of the specified filters. A split cannot have files from different pools.

getSplits

public InputSplit[] getSplits(JobConf job,
                              int numSplits)
                       throws IOException

Description copied from class: FileInputFormat

Splits files returned by FileInputFormat.listStatus(JobConf) when they're too big.

Specified by:

getSplits in interface InputFormat<K,V>

Overrides:

getSplits in class FileInputFormat<K,V>

Parameters:

job - job configuration.

numSplits - the desired number of splits, a hint.

Returns:

an array of InputSplits for the job.

Throws:

IOException

getRecordReader

public abstract RecordReader<K,V> getRecordReader(InputSplit split,
                                                  JobConf job,
                                                  Reporter reporter)
                                           throws IOException

This is not implemented yet.

Specified by:

getRecordReader in interface InputFormat<K,V>

Specified by:

getRecordReader in class FileInputFormat<K,V>

Parameters:

split - the InputSplit

job - the job that this split belongs to

Returns:

a RecordReader

Throws:

IOException