com.pervasive.datarush.io.compression

Interface CompressionFormat

All Superinterfaces:

Serializable

All Known Implementing Classes:

BZipCompression, GZipCompression, SnappyCompression, UncompressedData

public interface CompressionFormat
extends Serializable

Provides support for a compression format.

Field Summary

Fields

Modifier and Type	Field and Description
static CompressionFormat	NONE A format indicating no compression of data.

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.

Field Detail

NONE

static final CompressionFormat NONE

A format indicating no compression of data.

Method Detail

getName

String getName()

Gets the name of the compression algorithm.

Returns:

the well-known name of the compression format

isSplittable

boolean isSplittable()

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

Returns:

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

isCompressedFilename

boolean isCompressedFilename(String fileName)

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

Parameters:

fileName - the file name to check

Returns:

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

getUncompressedFilename

String getUncompressedFilename(String fileName)

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

Parameters:

fileName - the file name to process

Returns:

the expected name of the uncompressed file

getCompressedFilename

String getCompressedFilename(String fileName)

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

Parameters:

fileName - the file name to process

Returns:

the expected name of the compressed file

decompressStream

InputStream decompressStream(InputStream in)
                      throws IOException

Wraps the specified stream in a decompressor for the format.

Parameters:

in - the compressed byte stream to decompress

Returns:

the uncompressed data stream

Throws:

IOException - if an I/O error occurs

compressStream

OutputStream compressStream(OutputStream out)
                     throws IOException

Wraps the specified stream in a compressor for the format.

Parameters:

out - the uncompressed byte stream to compress

Returns:

the compressed data stream

Throws:

IOException - if an I/O error occurs

getSplitIterator

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

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.

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

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

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

Parameters:

split - split being read and decompressed

in - the compressed byte stream for a split to decompress

bufferSize -

Returns:

the uncompressed data stream

Throws:

IOException - if an I/O error occurs

UnsupportedOperationException - if the compression format does not support splitting