org.apache.hadoop.mapreduce.lib.input

Class FileInputFormat<K,V>

java.lang.Object

org.apache.hadoop.mapreduce.InputFormat<K,V>

org.apache.hadoop.mapreduce.lib.input.FileInputFormat<K,V>

Direct Known Subclasses:

CombineFileInputFormat, KeyValueTextInputFormat, NLineInputFormat, SequenceFileInputFormat, TextInputFormat

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

A base class for file-based InputFormats.

FileInputFormat is the base class for all file-based InputFormats. This provides a generic implementation of getSplits(JobContext). Subclasses of FileInputFormat can also override the isSplitable(JobContext, Path) method to ensure input-files are not split-up and are processed as a whole by Mappers.

Constructor Summary

Constructors

Constructor and Description
FileInputFormat()

Method Summary

Methods

Modifier and Type	Method and Description
static void	addInputPath(Job job, org.apache.hadoop.fs.Path path) Add a Path to the list of inputs for the map-reduce job.
static void	addInputPaths(Job job, java.lang.String commaSeparatedPaths) Add the given comma separated paths to the list of inputs for the map-reduce job.
protected long	computeSplitSize(long blockSize, long minSize, long maxSize)
protected int	getBlockIndex(org.apache.hadoop.fs.BlockLocation[] blkLocations, long offset)
protected long	getFormatMinSplitSize() Get the lower bound on split size imposed by the format.
static org.apache.hadoop.fs.PathFilter	getInputPathFilter(JobContext context) Get a PathFilter instance of the filter set for the input paths.
static org.apache.hadoop.fs.Path[]	getInputPaths(JobContext context) Get the list of input Paths for the map-reduce job.
static long	getMaxSplitSize(JobContext context) Get the maximum split size.
static long	getMinSplitSize(JobContext job) Get the minimum split size
java.util.List<InputSplit>	getSplits(JobContext job) Generate the list of files and make them into FileSplits.
protected boolean	isSplitable(JobContext context, org.apache.hadoop.fs.Path filename) Is the given filename splitable? Usually, true, but if the file is stream compressed, it will not be.
protected java.util.List<org.apache.hadoop.fs.FileStatus>	listStatus(JobContext job) List input directories.
static void	setInputPathFilter(Job job, java.lang.Class<? extends org.apache.hadoop.fs.PathFilter> filter) Set a PathFilter to be applied to the input paths for the map-reduce job.
static void	setInputPaths(Job job, org.apache.hadoop.fs.Path... inputPaths) Set the array of Paths as the list of inputs for the map-reduce job.
static void	setInputPaths(Job job, java.lang.String commaSeparatedPaths) Sets the given comma separated paths as the list of inputs for the map-reduce job.
static void	setMaxInputSplitSize(Job job, long size) Set the maximum split size
static void	setMinInputSplitSize(Job job, long size) Set the minimum input split size

Methods inherited from class org.apache.hadoop.mapreduce.InputFormat

createRecordReader

Methods inherited from class java.lang.Object

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

Constructor Detail

FileInputFormat

public FileInputFormat()

Method Detail

getFormatMinSplitSize

protected long getFormatMinSplitSize()

Get the lower bound on split size imposed by the format.

Returns:

the number of bytes of the minimal split for this format

isSplitable

protected boolean isSplitable(JobContext context,
                  org.apache.hadoop.fs.Path filename)

Is the given filename splitable? Usually, true, but if the file is stream compressed, it will not be. FileInputFormat implementations can override this and return false to ensure that individual input files are never split-up so that Mappers process entire files.

Parameters:

context - the job context

filename - the file name to check

Returns:

is this file splitable?

setInputPathFilter

public static void setInputPathFilter(Job job,
                      java.lang.Class<? extends org.apache.hadoop.fs.PathFilter> filter)

Set a PathFilter to be applied to the input paths for the map-reduce job.

Parameters:

job - the job to modify

filter - the PathFilter class use for filtering the input paths.

setMinInputSplitSize

public static void setMinInputSplitSize(Job job,
                        long size)

Set the minimum input split size

Parameters:

job - the job to modify

size - the minimum size

getMinSplitSize

public static long getMinSplitSize(JobContext job)

Get the minimum split size

Parameters:

job - the job

Returns:

the minimum number of bytes that can be in a split

setMaxInputSplitSize

public static void setMaxInputSplitSize(Job job,
                        long size)

Set the maximum split size

Parameters:

job - the job to modify

size - the maximum split size

getMaxSplitSize

public static long getMaxSplitSize(JobContext context)

Get the maximum split size.

Parameters:

context - the job to look at.

Returns:

the maximum number of bytes a split can include

getInputPathFilter

public static org.apache.hadoop.fs.PathFilter getInputPathFilter(JobContext context)

Get a PathFilter instance of the filter set for the input paths.

Returns:

the PathFilter instance set for the job, NULL if none has been set.

listStatus

protected java.util.List<org.apache.hadoop.fs.FileStatus> listStatus(JobContext job)
                                                              throws java.io.IOException

List input directories. Subclasses may override to, e.g., select only files matching a regular expression.

Parameters:

job - the job to list input paths for

Returns:

array of FileStatus objects

Throws:

java.io.IOException - if zero items.

getSplits

public java.util.List<InputSplit> getSplits(JobContext job)
                                     throws java.io.IOException

Generate the list of files and make them into FileSplits.

Specified by:

getSplits in class InputFormat<K,V>

Parameters:

job - job configuration.

Returns:

an array of InputSplits for the job.

Throws:

java.io.IOException

computeSplitSize

protected long computeSplitSize(long blockSize,
                    long minSize,
                    long maxSize)

getBlockIndex

protected int getBlockIndex(org.apache.hadoop.fs.BlockLocation[] blkLocations,
                long offset)

setInputPaths

public static void setInputPaths(Job job,
                 java.lang.String commaSeparatedPaths)
                          throws java.io.IOException

Sets the given comma separated paths as the list of inputs for the map-reduce job.

Parameters:

job - the job

commaSeparatedPaths - Comma separated paths to be set as the list of inputs for the map-reduce job.

Throws:

java.io.IOException

addInputPaths

public static void addInputPaths(Job job,
                 java.lang.String commaSeparatedPaths)
                          throws java.io.IOException

Add the given comma separated paths to the list of inputs for the map-reduce job.

Parameters:

job - The job to modify

commaSeparatedPaths - Comma separated paths to be added to the list of inputs for the map-reduce job.

Throws:

java.io.IOException

setInputPaths

public static void setInputPaths(Job job,
                 org.apache.hadoop.fs.Path... inputPaths)
                          throws java.io.IOException

Set the array of Paths as the list of inputs for the map-reduce job.

Parameters:

job - The job to modify

inputPaths - the Paths of the input directories/files for the map-reduce job.

Throws:

java.io.IOException

addInputPath

public static void addInputPath(Job job,
                org.apache.hadoop.fs.Path path)
                         throws java.io.IOException

Add a Path to the list of inputs for the map-reduce job.

Parameters:

job - The Job to modify

path - Path to be added to the list of inputs for the map-reduce job.

Throws:

java.io.IOException

getInputPaths

public static org.apache.hadoop.fs.Path[] getInputPaths(JobContext context)

Get the list of input Paths for the map-reduce job.

Parameters:

context - The job

Returns:

the list of input Paths for the map-reduce job.