org.apache.hadoop.mapred.lib

Class CombineFileInputFormat<K,V>

java.lang.Object

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

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

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

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

All Implemented Interfaces:

InputFormat<K,V>

Direct Known Subclasses:

CombineSequenceFileInputFormat, CombineTextInputFormat

@InterfaceAudience.Public
 @InterfaceStability.Stable
public abstract class CombineFileInputFormat<K,V>
extends CombineFileInputFormat<K,V>
implements InputFormat<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

Field Summary

Fields inherited from class org.apache.hadoop.mapreduce.lib.input.CombineFileInputFormat

SPLIT_MINSIZE_PERNODE, SPLIT_MINSIZE_PERRACK

Fields inherited from class org.apache.hadoop.mapreduce.lib.input.FileInputFormat

DEFAULT_LIST_STATUS_NUM_THREADS, INPUT_DIR, INPUT_DIR_RECURSIVE, LIST_STATUS_NUM_THREADS, NUM_INPUT_FILES, PATHFILTER_CLASS, SPLIT_MAXSIZE, SPLIT_MINSIZE

Constructor Summary

Constructors

Constructor and Description
CombineFileInputFormat() default constructor

Method Summary

Modifier and Type	Method and Description
protected void	createPool(JobConf conf, List<PathFilter> filters) Deprecated. Use CombineFileInputFormat.createPool(List).
protected void	createPool(JobConf conf, PathFilter... filters) Deprecated. Use CombineFileInputFormat.createPool(PathFilter...).
RecordReader<K,V>	createRecordReader(InputSplit split, TaskAttemptContext context) This is not implemented yet.
abstract RecordReader<K,V>	getRecordReader(InputSplit split, JobConf job, Reporter reporter) This is not implemented yet.
InputSplit[]	getSplits(JobConf job, int numSplits) Logically split the set of input files for the job.
protected boolean	isSplitable(FileSystem fs, Path file)
protected FileStatus[]	listStatus(JobConf job) List input directories.

Methods inherited from class org.apache.hadoop.mapreduce.lib.input.CombineFileInputFormat

createPool, createPool, getFileBlockLocations, getSplits, isSplitable, setMaxSplitSize, setMinSplitSizeNode, setMinSplitSizeRack

Methods inherited from class org.apache.hadoop.mapreduce.lib.input.FileInputFormat

addInputPath, addInputPathRecursively, addInputPaths, computeSplitSize, getBlockIndex, getFormatMinSplitSize, getInputDirRecursive, getInputPathFilter, getInputPaths, getMaxSplitSize, getMinSplitSize, listStatus, makeSplit, makeSplit, setInputDirRecursive, setInputPathFilter, setInputPaths, setInputPaths, setMaxInputSplitSize, setMinInputSplitSize

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

getSplits

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

Description copied from interface: InputFormat

Logically split the set of input files for the job.

Each InputSplit is then assigned to an individual Mapper for processing.

Note: The split is a logical split of the inputs and the input files are not physically split into chunks. For e.g. a split could be <input-file-path, start, offset> tuple.

Specified by:

getSplits in interface InputFormat<K,V>

Parameters:

job - job configuration.

numSplits - the desired number of splits, a hint.

Returns:

an array of InputSplits for the job.

Throws:

IOException

createPool

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

Deprecated. Use CombineFileInputFormat.createPool(List).

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

createPool

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

Deprecated. Use CombineFileInputFormat.createPool(PathFilter...).

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.

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>

Parameters:

split - the InputSplit

job - the job that this split belongs to

Returns:

a RecordReader

Throws:

IOException

createRecordReader

public RecordReader<K,V> createRecordReader(InputSplit split,
                                            TaskAttemptContext context)
                                     throws IOException

Description copied from class: CombineFileInputFormat

This is not implemented yet.

Specified by:

createRecordReader in class CombineFileInputFormat<K,V>

Parameters:

split - the split to be read

context - the information about the task

Returns:

a new record reader

Throws:

IOException

listStatus

protected FileStatus[] listStatus(JobConf job)
                           throws 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:

IOException - if zero items.

isSplitable

protected boolean isSplitable(FileSystem fs,
                              Path file)