Package org.apache.hadoop.io.compress

Class PassthroughCodec

java.lang.Object

org.apache.hadoop.io.compress.PassthroughCodec

All Implemented Interfaces:

Configurable, CompressionCodec

@Public
@Unstable
public class PassthroughCodec
extends java.lang.Object
implements Configurable, CompressionCodec

This is a special codec which does not transform the output. It can be declared as a codec in the option "io.compression.codecs", and then it will declare that it supports the file extension set in OPT_EXTENSION. This allows decompression to be disabled on a job, even when there is a registered/discoverable decompression codec for a file extension -without having to change the standard codec binding mechanism. For example, to disable decompression for a gzipped files, set the options

   io.compression.codecs = org.apache.hadoop.io.compress.PassthroughCodec
   io.compress.passthrough.extension = .gz
 

Note: this is not a Splittable codec: it doesn't know the capabilities of the passed in stream. It should be possible to extend this in a subclass: the inner classes are marked as protected to enable this. Do not retrofit splitting to this class..

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	PassthroughCodec.PassthroughDecompressorStream	The decompressor.
protected static class	PassthroughCodec.StubDecompressor	The decompressor is a no-op.

Nested classes/interfaces inherited from interface org.apache.hadoop.io.compress.CompressionCodec

CompressionCodec.Util

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	CLASSNAME	Classname of the codec: "org.apache.hadoop.io.compress.PassthroughCodec".
static java.lang.String	DEFAULT_EXTENSION	This default extension is here so that if no extension has been defined, some value is still returned: ".passthrough"..
static java.lang.String	OPT_EXTENSION	Option to control the extension of the code: "io.compress.passthrough.extension".

Constructor Summary

Constructors

Constructor	Description
PassthroughCodec()

Method Summary

Modifier and Type	Method	Description
Compressor	createCompressor()	Create a new Compressor for use by this CompressionCodec.
Decompressor	createDecompressor()	Create a new Decompressor for use by this CompressionCodec.
CompressionInputStream	createInputStream(java.io.InputStream in)	Create a CompressionInputStream that will read from the given input stream.
CompressionInputStream	createInputStream(java.io.InputStream in, Decompressor decompressor)	Create a CompressionInputStream that will read from the given InputStream with the given Decompressor.
CompressionOutputStream	createOutputStream(java.io.OutputStream out)	Create a CompressionOutputStream that will write to the given OutputStream.
CompressionOutputStream	createOutputStream(java.io.OutputStream out, Compressor compressor)	Create a CompressionOutputStream that will write to the given OutputStream with the given Compressor.
java.lang.Class<? extends Compressor>	getCompressorType()	Get the type of Compressor needed by this CompressionCodec.
Configuration	getConf()	Return the configuration used by this object.
java.lang.Class<? extends Decompressor>	getDecompressorType()	Get the type of Decompressor needed by this CompressionCodec.
java.lang.String	getDefaultExtension()	Get the default filename extension for this kind of compression.
void	setConf(Configuration conf)	Set the configuration to be used by this object.

Methods inherited from class java.lang.Object

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

Field Detail

CLASSNAME

public static final java.lang.String CLASSNAME

Classname of the codec: "org.apache.hadoop.io.compress.PassthroughCodec".

See Also:

Constant Field Values

OPT_EXTENSION

public static final java.lang.String OPT_EXTENSION

Option to control the extension of the code: "io.compress.passthrough.extension".

See Also:

Constant Field Values

DEFAULT_EXTENSION

public static final java.lang.String DEFAULT_EXTENSION

This default extension is here so that if no extension has been defined, some value is still returned: ".passthrough"..

See Also:

Constant Field Values

Constructor Detail

PassthroughCodec

public PassthroughCodec()

Method Detail

getConf

public Configuration getConf()

Description copied from interface: Configurable

Return the configuration used by this object.

Specified by:

getConf in interface Configurable

Returns:

Configuration

setConf

public void setConf(Configuration conf)

Description copied from interface: Configurable

Set the configuration to be used by this object.

Specified by:

setConf in interface Configurable

Parameters:

conf - configuration to be used

getDefaultExtension

public java.lang.String getDefaultExtension()

Description copied from interface: CompressionCodec

Get the default filename extension for this kind of compression.

Specified by:

getDefaultExtension in interface CompressionCodec

Returns:

the extension including the '.'

createOutputStream

public CompressionOutputStream createOutputStream(java.io.OutputStream out)
                                           throws java.io.IOException

Description copied from interface: CompressionCodec

Create a CompressionOutputStream that will write to the given OutputStream.

Specified by:

createOutputStream in interface CompressionCodec

Parameters:

out - the location for the final output stream

Returns:

a stream the user can write uncompressed data to have it compressed

Throws:

java.io.IOException - raised on errors performing I/O.

createOutputStream

public CompressionOutputStream createOutputStream(java.io.OutputStream out,
                                                  Compressor compressor)
                                           throws java.io.IOException

Description copied from interface: CompressionCodec

Create a CompressionOutputStream that will write to the given OutputStream with the given Compressor.

Specified by:

createOutputStream in interface CompressionCodec

Parameters:

out - the location for the final output stream

compressor - compressor to use

Returns:

a stream the user can write uncompressed data to have it compressed

Throws:

java.io.IOException - raised on errors performing I/O.

getCompressorType

public java.lang.Class<? extends Compressor> getCompressorType()

Description copied from interface: CompressionCodec

Get the type of Compressor needed by this CompressionCodec.

Specified by:

getCompressorType in interface CompressionCodec

Returns:

the type of compressor needed by this codec.

createCompressor

public Compressor createCompressor()

Description copied from interface: CompressionCodec

Create a new Compressor for use by this CompressionCodec.

Specified by:

createCompressor in interface CompressionCodec

Returns:

a new compressor for use by this codec

createInputStream

public CompressionInputStream createInputStream(java.io.InputStream in)
                                         throws java.io.IOException

Description copied from interface: CompressionCodec

Create a CompressionInputStream that will read from the given input stream.

Specified by:

createInputStream in interface CompressionCodec

Parameters:

in - the stream to read compressed bytes from

Returns:

a stream to read uncompressed bytes from

Throws:

java.io.IOException - raised on errors performing I/O.

createInputStream

public CompressionInputStream createInputStream(java.io.InputStream in,
                                                Decompressor decompressor)
                                         throws java.io.IOException

Description copied from interface: CompressionCodec

Create a CompressionInputStream that will read from the given InputStream with the given Decompressor.

Specified by:

createInputStream in interface CompressionCodec

Parameters:

in - the stream to read compressed bytes from

decompressor - decompressor to use

Returns:

a stream to read uncompressed bytes from

Throws:

java.io.IOException - raised on errors performing I/O.

getDecompressorType

public java.lang.Class<? extends Decompressor> getDecompressorType()

Description copied from interface: CompressionCodec

Get the type of Decompressor needed by this CompressionCodec.

Specified by:

getDecompressorType in interface CompressionCodec

Returns:

the type of decompressor needed by this codec.

createDecompressor

public Decompressor createDecompressor()

Description copied from interface: CompressionCodec

Create a new Decompressor for use by this CompressionCodec.

Specified by:

createDecompressor in interface CompressionCodec

Returns:

a new decompressor for use by this codec