org.snf4j.core.codec.zip

Class ZlibEncoder

java.lang.Object

org.snf4j.core.codec.zip.ZlibCodec

org.snf4j.core.codec.zip.ZlibEncoder

All Implemented Interfaces:

ICodec<byte[],ByteBuffer>, IEncoder<byte[],ByteBuffer>, IEventDrivenCodec

Direct Known Subclasses:

GzipEncoder

public class ZlibEncoder
extends ZlibCodec
implements IEncoder<byte[],ByteBuffer>, IEventDrivenCodec

Compresses an array of bytes using the zlib compression.

Author:

SNF4J.ORG

Nested Class Summary

Nested classes/interfaces inherited from class org.snf4j.core.codec.zip.ZlibCodec

ZlibCodec.Mode

Field Summary

Fields

Modifier and Type	Field and Description
protected Deflater	deflater The compressor used by this class to compress data.

Constructor Summary

Constructors

Modifier	Constructor and Description
	ZlibEncoder() Creates a new zlib encoder with the default compression level (6) and the default mode (ZLIB).
	ZlibEncoder(byte[] dictionary) Creates a new zlib encoder with a preset dictionary for compression, the default compression level (6) and the default mode (ZLIB).
	ZlibEncoder(int level) Creates a new zlib encoder with the specified compression level and the default mode (ZLIB).
	ZlibEncoder(int level, byte[] dictionary) Creates a new zlib encoder with the specified compression level and a preset dictionary.
protected	ZlibEncoder(int level, byte[] dictionary, ZlibCodec.Mode mode) Creates a new zlib encoder with the specified compression level, a preset dictionary and the mode.
	ZlibEncoder(int level, ZlibCodec.Mode mode) Creates a new zlib encoder with the specified compression level and the mode.

Method Summary

Modifier and Type	Method and Description
void	added(ISession session, ICodecPipeline pipeline) Does nothing.
protected int	deflateBound(int len) Returns upper bound on the compressed size.
void	encode(ISession session, byte[] data, List<ByteBuffer> out) Compresses the input data.
void	event(ISession session, SessionEvent event) Finishes the compression when the associated session is ending (SessionEvent.ENDING).
void	finish() Requests finishing of the compression.
boolean	isFinished() Tells if the compression has been finished.
protected void	postFinish(ISession session, ByteBuffer out) Called right after the compression has been finished.
protected void	preDeflate(ISession session, byte[] in, ByteBuffer out) Called right before compression of a portion of uncompressed data.
protected void	preFinish(ISession session, ByteBuffer out) Called right before finishing of the compression.
void	removed(ISession session, ICodecPipeline pipeline) Does nothing.

Methods inherited from class org.snf4j.core.codec.zip.ZlibCodec

getInboundType, getOutboundType

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.snf4j.core.codec.ICodec

getInboundType, getOutboundType

Field Detail

deflater

protected Deflater deflater

The compressor used by this class to compress data.

Constructor Detail

ZlibEncoder

public ZlibEncoder()

Creates a new zlib encoder with the default compression level (6) and the default mode (ZLIB).

ZlibEncoder

public ZlibEncoder(int level)

Creates a new zlib encoder with the specified compression level and the default mode (ZLIB).

Parameters:

level - the compression level (0 - 9). 1 yields the fastest compression and 9 yields the best compression. 0 means no compression. The default compression level is 6.

Throws:

IllegalArgumentException - if the compression level is out of range

ZlibEncoder

public ZlibEncoder(byte[] dictionary)

Creates a new zlib encoder with a preset dictionary for compression, the default compression level (6) and the default mode (ZLIB).

Parameters:

dictionary - the preset dictionary or null if no preset dictionary should be used

ZlibEncoder

public ZlibEncoder(int level,
                   ZlibCodec.Mode mode)

Creates a new zlib encoder with the specified compression level and the mode.

Parameters:

level - the compression level (0 - 9). 1 yields the fastest compression and 9 yields the best compression. 0 means no compression. The default compression level is 6.

mode - the mode for the zlib encoder (AUTO means ZLIB)

Throws:

IllegalArgumentException - if the compression level is out of range

NullPointerException - if the mode is null

ZlibEncoder

public ZlibEncoder(int level,
                   byte[] dictionary)

Creates a new zlib encoder with the specified compression level and a preset dictionary.

Parameters:

level - the compression level (0 - 9). 1 yields the fastest compression and 9 yields the best compression. 0 means no compression. The default compression level is 6.

dictionary - the preset dictionary or null if no preset dictionary should be used

Throws:

IllegalArgumentException - if the compression level is out of range

ZlibEncoder

protected ZlibEncoder(int level,
                      byte[] dictionary,
                      ZlibCodec.Mode mode)

Creates a new zlib encoder with the specified compression level, a preset dictionary and the mode.

Parameters:

level - the compression level (0 - 9). 1 yields the fastest compression and 9 yields the best compression. 0 means no compression. The default compression level is 6.

dictionary - the preset dictionary or null if no preset dictionary should be used

mode - the mode for the zlib encoder (AUTO means ZLIB)

Throws:

IllegalArgumentException - if the compression level is out of range

NullPointerException - if the mode is null

Method Detail

deflateBound

protected int deflateBound(int len)

Returns upper bound on the compressed size.

Parameters:

len - the length of the uncompressed data.

Returns:

the upper bound

preDeflate

protected void preDeflate(ISession session,
                          byte[] in,
                          ByteBuffer out)
                   throws Exception

Called right before compression of a portion of uncompressed data. It can be used, for example, to generate a customized header.

Parameters:

session - the session object the encoder is associated with

in - the uncompressed input data

out - the output buffer

Throws:

Exception - if an error has occurred

preFinish

protected void preFinish(ISession session,
                         ByteBuffer out)
                  throws Exception

Called right before finishing of the compression. It can be used, for example, to generate a customized header if the compression was finished without compressing any data.

Parameters:

session - the session object the encoder is associated with

out - the output buffer

Throws:

Exception - if an error has occurred

postFinish

protected void postFinish(ISession session,
                          ByteBuffer out)
                   throws Exception

Called right after the compression has been finished. It can be used, for example, to generate a customized footer.

Parameters:

session - the session object the encoder is associated with

out - the output buffer

Throws:

Exception - if an error has occurred

finish

public void finish()

Requests finishing of the compression. Any data processed by this encoder after calling this method will not be compressed (will be passed to the output list without any change).

isFinished

public boolean isFinished()

Tells if the compression has been finished.

Returns:

true if the compression has been finished.

encode

public void encode(ISession session,
                   byte[] data,
                   List<ByteBuffer> out)
            throws Exception

Compresses the input data.

Specified by:

encode in interface IEncoder<byte[],ByteBuffer>

Parameters:

session - the ISession which the passed data belongs to

data - the data to decode to another one

out - the List to which the decoded data should be added, or null if O is Void

Throws:

Exception - is thrown, if an error occur

added

public void added(ISession session,
                  ICodecPipeline pipeline)

Does nothing.

Specified by:

added in interface IEventDrivenCodec

Parameters:

session - the session the pipeline is associated with

pipeline - the pipeline the codec has been added to

event

public void event(ISession session,
                  SessionEvent event)

Finishes the compression when the associated session is ending (SessionEvent.ENDING).

Specified by:

event in interface IEventDrivenCodec

Parameters:

session - the session which state is changing

event - the session event

removed

public void removed(ISession session,
                    ICodecPipeline pipeline)

Does nothing.

Specified by:

removed in interface IEventDrivenCodec

Parameters:

session - the session the pipeline is associated with

pipeline - the pipeline the codec has been removed from