org.apache.hadoop.mapreduce.task.reduce

Class ShuffleHeader

java.lang.Object

org.apache.hadoop.mapreduce.task.reduce.ShuffleHeader

All Implemented Interfaces:

Writable

@InterfaceAudience.Private
@InterfaceStability.Stable
public class ShuffleHeader
extends Object
implements Writable

Shuffle Header information that is sent by the TaskTracker and deciphered by the Fetcher thread of Reduce task

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_HTTP_HEADER_NAME
static String	DEFAULT_HTTP_HEADER_VERSION
static String	HTTP_HEADER_NAME Header info of the shuffle http request/response
static String	HTTP_HEADER_VERSION

Constructor Summary

Constructors

Constructor and Description
ShuffleHeader()
ShuffleHeader(String mapId, long compressedLength, long uncompressedLength, int forReduce)

Method Summary

Methods

Modifier and Type	Method and Description
void	readFields(DataInput in) Deserialize the fields of this object from in.
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, toString, wait, wait, wait

Field Detail

HTTP_HEADER_NAME

public static final String HTTP_HEADER_NAME

Header info of the shuffle http request/response

See Also:

Constant Field Values

DEFAULT_HTTP_HEADER_NAME

public static final String DEFAULT_HTTP_HEADER_NAME

See Also:

Constant Field Values

HTTP_HEADER_VERSION

public static final String HTTP_HEADER_VERSION

See Also:

Constant Field Values

DEFAULT_HTTP_HEADER_VERSION

public static final String DEFAULT_HTTP_HEADER_VERSION

See Also:

Constant Field Values

Constructor Detail

ShuffleHeader

public ShuffleHeader()

ShuffleHeader

public ShuffleHeader(String mapId,
             long compressedLength,
             long uncompressedLength,
             int forReduce)

Method Detail

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

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