org.apache.pig

Class PigStreamingBase

java.lang.Object

org.apache.pig.PigStreamingBase

All Implemented Interfaces:

PigToStream, StreamToPig

Direct Known Subclasses:

PigStreaming, PigStreamingUDF

@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class PigStreamingBase
extends Object
implements PigToStream, StreamToPig

The interface is used for the custom mapping of - a Tuple to a byte array. The byte array is fed to the stdin of the streaming process. - a byte array, received from the stdout of the streaming process, to a Tuple. This interface is designed to provide a common protocol for data exchange between Pig runtime and streaming executables. Typically, a user implements this interface for a particular type of stream command and specifies the implementation class in the Pig DEFINE statement.

Since:

Pig 0.12

Constructor Summary

Constructors

Constructor and Description
PigStreamingBase()

Method Summary

Methods

Modifier and Type	Method and Description
Tuple	deserialize(byte[] bytes) Deprecated.
abstract Tuple	deserialize(byte[] bytes, int offset, int length) Given a byte array from a streaming executable, produce a tuple.
abstract LoadCaster	getLoadCaster() This will be called on the front end during planning and not on the back end during execution.
byte[]	serialize(Tuple t) Deprecated.
abstract WritableByteArray	serializeToBytes(Tuple t) Given a tuple, produce an array of bytes to be passed to the streaming executable.

Methods inherited from class java.lang.Object

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

Constructor Detail

PigStreamingBase

public PigStreamingBase()

Method Detail

serialize

@Deprecated
public final byte[] serialize(Tuple t)
                       throws IOException

Deprecated.

Description copied from interface: PigToStream

Given a tuple, produce an array of bytes to be passed to the streaming executable.

Specified by:

serialize in interface PigToStream

Parameters:

t - Tuple to serialize

Returns:

Serialized form of the tuple

Throws:

IOException

serializeToBytes

public abstract WritableByteArray serializeToBytes(Tuple t)
                                            throws IOException

Given a tuple, produce an array of bytes to be passed to the streaming executable.

Parameters:

t - Tuple to serialize

Returns:

Serialized form of the tuple

Throws:

IOException

deserialize

@Deprecated
public final Tuple deserialize(byte[] bytes)
                        throws IOException

Deprecated.

Description copied from interface: StreamToPig

Given a byte array from a streaming executable, produce a tuple.

Specified by:

deserialize in interface StreamToPig

Parameters:

bytes - to deserialize.

Returns:

Data as a Pig Tuple.

Throws:

IOException

deserialize

public abstract Tuple deserialize(byte[] bytes,
                int offset,
                int length)
                           throws IOException

Given a byte array from a streaming executable, produce a tuple.

Parameters:

bytes - bytes to deserialize.

offset - the offset in the byte array from which to deserialize.

length - the number of bytes from the offset of the byte array to deserialize.

Returns:

Data as a Pig Tuple.

Throws:

IOException

getLoadCaster

public abstract LoadCaster getLoadCaster()
                                  throws IOException

This will be called on the front end during planning and not on the back end during execution.

Specified by:

getLoadCaster in interface StreamToPig

Returns:

the LoadCaster associated with this object, or null if there is no such LoadCaster.

Throws:

IOException - if there is an exception during LoadCaster