org.apache.hadoop.mapreduce.lib.input

Class FileSplit

java.lang.Object

org.apache.hadoop.mapreduce.InputSplit

org.apache.hadoop.mapreduce.lib.input.FileSplit

All Implemented Interfaces:

Writable

@InterfaceAudience.Public
@InterfaceStability.Stable
public class FileSplit
extends InputSplit
implements Writable

A section of an input file. Returned by InputFormat.getSplits(JobContext) and passed to InputFormat.createRecordReader(InputSplit,TaskAttemptContext).

Constructor Summary

Constructors

Constructor and Description
FileSplit()
FileSplit(Path file, long start, long length, String[] hosts) Constructs a split with host information
FileSplit(Path file, long start, long length, String[] hosts, String[] inMemoryHosts) Constructs a split with host and cached-blocks information

Method Summary

Methods

Modifier and Type	Method and Description
long	getLength() The number of bytes in the file to process.
SplitLocationInfo[]	getLocationInfo() Gets info about which nodes the input split is stored on and how it is stored at each location.
String[]	getLocations() Get the list of nodes by name where the data for the split would be local.
Path	getPath() The file containing this split's data.
long	getStart() The position of the first byte in the file to process.
void	readFields(DataInput in) Deserialize the fields of this object from in.
String	toString()
void	write(DataOutput out) Serialize the fields of this object to out.

Methods inherited from class java.lang.Object

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

Constructor Detail

FileSplit

public FileSplit()

FileSplit

public FileSplit(Path file,
         long start,
         long length,
         String[] hosts)

Constructs a split with host information

Parameters:

file - the file name

start - the position of the first byte in the file to process

length - the number of bytes in the file to process

hosts - the list of hosts containing the block, possibly null

FileSplit

public FileSplit(Path file,
         long start,
         long length,
         String[] hosts,
         String[] inMemoryHosts)

Constructs a split with host and cached-blocks information

Parameters:

file - the file name

start - the position of the first byte in the file to process

length - the number of bytes in the file to process

hosts - the list of hosts containing the block

inMemoryHosts - the list of hosts containing the block in memory

Method Detail

getPath

public Path getPath()

The file containing this split's data.

getStart

public long getStart()

The position of the first byte in the file to process.

getLength

public long getLength()

The number of bytes in the file to process.

Specified by:

getLength in class InputSplit

Returns:

the number of bytes in the split

toString

public String toString()

Overrides:

toString in class Object

write

public void write(DataOutput out)
           throws IOException

Description copied from interface: Writable

Serialize the fields of this object to out.

Specified by:

write in interface Writable

Parameters:

out - DataOuput to serialize this object into.

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Description copied from interface: Writable

Deserialize the fields of this object from in.

For efficiency, implementations should attempt to re-use storage in the existing object where possible.

Specified by:

readFields in interface Writable

Parameters:

in - DataInput to deseriablize this object from.

Throws:

IOException

getLocations

public String[] getLocations()
                      throws IOException

Description copied from class: InputSplit

Get the list of nodes by name where the data for the split would be local. The locations do not need to be serialized.

Specified by:

getLocations in class InputSplit

Returns:

a new array of the node nodes.

Throws:

IOException

getLocationInfo

@InterfaceStability.Evolving
public SplitLocationInfo[] getLocationInfo()
                                    throws IOException

Description copied from class: InputSplit

Gets info about which nodes the input split is stored on and how it is stored at each location.

Overrides:

getLocationInfo in class InputSplit

Returns:

list of SplitLocationInfos describing how the split data is stored at each location. A null value indicates that all the locations have the data stored on disk.

Throws:

IOException