com.pervasive.datarush.io.compression

Class GZipCompression

java.lang.Object

com.pervasive.datarush.io.compression.GZipCompression

All Implemented Interfaces:

CompressionFormat, Serializable

public class GZipCompression
extends Object
implements CompressionFormat

Defines support for the gzip compression algorithm.

See Also:

Serialized Form

Field Summary

Fields inherited from interface com.pervasive.datarush.io.compression.CompressionFormat

NONE

Constructor Summary

Constructors

Constructor and Description
GZipCompression()

Method Summary

Modifier and Type	Method and Description
OutputStream	compressStream(OutputStream out) Wraps the specified stream in a compressor for the format.
SplitInputStream	decompressSplitStream(DataSplit split, InputStream in, int bufferSize) Wraps the specified stream for a split in a decompressor for the format.
InputStream	decompressStream(InputStream in) Wraps the specified stream in a decompressor for the format.
String	getCompressedFilename(String fileName) Adds the common file suffix associated with this format to the given file name.
String	getName() Gets the name of the compression algorithm.
SplitIterator	getSplitIterator(FileClient client, Path filePath, SplitOptions options) Create a SplitIterator for the given file path and options.
String	getUncompressedFilename(String fileName) Strips any file suffix associated with this format from the given file name.
boolean	isCompressedFilename(String fileName) Indicates whether the specified file name is compressed in this format.
boolean	isSplittable() Indicates whether compressed data files may be split.

Methods inherited from class java.lang.Object

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

Constructor Detail

GZipCompression

public GZipCompression()

Method Detail

getName

public String getName()

Description copied from interface: CompressionFormat

Gets the name of the compression algorithm.

Specified by:

getName in interface CompressionFormat

Returns:

the well-known name of the compression format

isSplittable

public boolean isSplittable()

Description copied from interface: CompressionFormat

Indicates whether compressed data files may be split. Generally, compressed data cannot be split.

Specified by:

isSplittable in interface CompressionFormat

Returns:

true if the compression format allow file splits, false otherwise.

isCompressedFilename

public boolean isCompressedFilename(String fileName)

Description copied from interface: CompressionFormat

Indicates whether the specified file name is compressed in this format. Generally, this is done by looking at the file suffix.

Specified by:

isCompressedFilename in interface CompressionFormat

Parameters:

fileName - the file name to check

Returns:

true if the file is believed to be compressed in this format, false otherwise.

getUncompressedFilename

public String getUncompressedFilename(String fileName)

Description copied from interface: CompressionFormat

Strips any file suffix associated with this format from the given file name.

Specified by:

getUncompressedFilename in interface CompressionFormat

Parameters:

fileName - the file name to process

Returns:

the expected name of the uncompressed file

getCompressedFilename

public String getCompressedFilename(String fileName)

Description copied from interface: CompressionFormat

Adds the common file suffix associated with this format to the given file name.

Specified by:

getCompressedFilename in interface CompressionFormat

Parameters:

fileName - the file name to process

Returns:

the expected name of the compressed file

decompressStream

public InputStream decompressStream(InputStream in)
                             throws IOException

Description copied from interface: CompressionFormat

Wraps the specified stream in a decompressor for the format.

Specified by:

decompressStream in interface CompressionFormat

Parameters:

in - the compressed byte stream to decompress

Returns:

the uncompressed data stream

Throws:

IOException - if an I/O error occurs

compressStream

public OutputStream compressStream(OutputStream out)
                            throws IOException

Description copied from interface: CompressionFormat

Wraps the specified stream in a compressor for the format.

Specified by:

compressStream in interface CompressionFormat

Parameters:

out - the uncompressed byte stream to compress

Returns:

the compressed data stream

Throws:

IOException - if an I/O error occurs

getSplitIterator

public SplitIterator getSplitIterator(FileClient client,
                                      Path filePath,
                                      SplitOptions options)
                               throws IOException

Description copied from interface: CompressionFormat

Create a SplitIterator for the given file path and options. Iterators may vary based on the compression format of an input data stream or if the input is not compressed. For instance, compression formats that do not support splitting will create an iterator with a single split: the whole file.

Specified by:

getSplitIterator in interface CompressionFormat

Parameters:

client - the file client in use

filePath - path to the input file

options - splitting options

Returns:

an iterator of the split(s) for the input file

Throws:

IOException - if an I/O error occurs

decompressSplitStream

public SplitInputStream decompressSplitStream(DataSplit split,
                                              InputStream in,
                                              int bufferSize)
                                       throws IOException

Description copied from interface: CompressionFormat

Wraps the specified stream for a split in a decompressor for the format. The format must be splittable or an UnsupportedOperationException will be thrown.

Specified by:

decompressSplitStream in interface CompressionFormat

Parameters:

split - split being read and decompressed

in - the compressed byte stream for a split to decompress

Returns:

the uncompressed data stream

Throws:

IOException - if an I/O error occurs