org.apache.mina.filter.compression

Class Zlib

java.lang.Object

org.apache.mina.filter.compression.Zlib

class Zlib
extends java.lang.Object

A helper class for interfacing with the JZlib library. This class acts both as a compressor and decompressor, but only as one at a time. The only flush method supported is Z_SYNC_FLUSH also known as Z_PARTIAL_FLUSH

Field Summary

Fields

Modifier and Type	Field and Description
static int	COMPRESSION_DEFAULT Default compression
static int	COMPRESSION_MAX Try o get the best possible compression
static int	COMPRESSION_MIN Favor speed over compression ratio
static int	COMPRESSION_NONE No compression
private int	compressionLevel The requested compression level
private int	mode The selected operation mode : INFLATE or DEFLATE
static int	MODE_DEFLATER Compression mode
static int	MODE_INFLATER Uncompress mode
private com.jcraft.jzlib.ZStream	zStream The inner stream used to inflate or deflate the data

Constructor Summary

Constructors

Constructor and Description
Zlib(int compressionLevel, int mode) Creates an instance of the ZLib class.

Method Summary

Modifier and Type	Method and Description
void	cleanUp() Cleans up the resources used by the compression library.
IoBuffer	deflate(IoBuffer inBuffer) Compress the input.
IoBuffer	inflate(IoBuffer inBuffer) Uncompress the given buffer, returning it in a new buffer.

Methods inherited from class java.lang.Object

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

Field Detail

COMPRESSION_MAX

public static final int COMPRESSION_MAX

Try o get the best possible compression

See Also:

Constant Field Values

COMPRESSION_MIN

public static final int COMPRESSION_MIN

Favor speed over compression ratio

See Also:

Constant Field Values

COMPRESSION_NONE

public static final int COMPRESSION_NONE

No compression

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Constant Field Values

COMPRESSION_DEFAULT

public static final int COMPRESSION_DEFAULT

Default compression

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Constant Field Values

MODE_DEFLATER

public static final int MODE_DEFLATER

Compression mode

See Also:

Constant Field Values

MODE_INFLATER

public static final int MODE_INFLATER

Uncompress mode

See Also:

Constant Field Values

compressionLevel

private int compressionLevel

The requested compression level

zStream

private com.jcraft.jzlib.ZStream zStream

The inner stream used to inflate or deflate the data

mode

private int mode

The selected operation mode : INFLATE or DEFLATE

Constructor Detail

Zlib

public Zlib(int compressionLevel,
            int mode)

Creates an instance of the ZLib class.

Parameters:

compressionLevel - the level of compression that should be used. One of COMPRESSION_MAX, COMPRESSION_MIN, COMPRESSION_NONE or COMPRESSION_DEFAULT

mode - the mode in which the instance will operate. Can be either of MODE_DEFLATER or MODE_INFLATER

Throws:

java.lang.IllegalArgumentException - if the mode is incorrect

Method Detail

inflate

public IoBuffer inflate(IoBuffer inBuffer)
                 throws java.io.IOException

Uncompress the given buffer, returning it in a new buffer.

Parameters:

inBuffer - the IoBuffer to be decompressed. The contents of the buffer are transferred into a local byte array and the buffer is flipped and returned intact.

Returns:

the decompressed data

Throws:

java.io.IOException - if the decompression of the data failed for some reason.

java.lang.IllegalArgumentException - if the mode is not MODE_DEFLATER

deflate

public IoBuffer deflate(IoBuffer inBuffer)
                 throws java.io.IOException

Compress the input. The result will be put in a new buffer.

Parameters:

inBuffer - the buffer to be compressed. The contents are transferred into a local byte array and the buffer is flipped and returned intact.

Returns:

the buffer with the compressed data

Throws:

java.io.IOException - if the compression of teh buffer failed for some reason

java.lang.IllegalStateException - if the mode is not MODE_DEFLATER

cleanUp

public void cleanUp()

Cleans up the resources used by the compression library.