Class ZlibEncoder

java.lang.Object

org.jboss.netty.handler.codec.oneone.OneToOneEncoder

org.jboss.netty.handler.codec.oneone.OneToOneStrictEncoder

org.jboss.netty.handler.codec.compression.ZlibEncoder

All Implemented Interfaces:

ChannelDownstreamHandler, ChannelHandler, LifeCycleAwareChannelHandler

public class ZlibEncoder
extends OneToOneStrictEncoder
implements LifeCycleAwareChannelHandler

Compresses a ChannelBuffer using the deflate algorithm.

Nested Class Summary

Nested classes/interfaces inherited from interface ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private ChannelHandlerContext	ctx
private static final byte[]	EMPTY_ARRAY
private final AtomicBoolean	finished
private final int	wrapperOverhead
private final com.jcraft.jzlib.ZStream	z

Constructor Summary

Constructors

Constructor	Description
ZlibEncoder()	Creates a new zlib encoder with the default compression level (6), default window bits (15), default memory level (8), and the default wrapper (ZlibWrapper.ZLIB).
ZlibEncoder(byte[] dictionary)	Creates a new zlib encoder with the default compression level (6), default window bits (15), default memory level (8), and the specified preset dictionary.
ZlibEncoder(int compressionLevel)	Creates a new zlib encoder with the specified compressionLevel, default window bits (15), default memory level (8), and the default wrapper (ZlibWrapper.ZLIB).
ZlibEncoder(int compressionLevel, byte[] dictionary)	Creates a new zlib encoder with the specified compressionLevel, default window bits (15), default memory level (8), and the specified preset dictionary.
ZlibEncoder(int compressionLevel, int windowBits, int memLevel, byte[] dictionary)	Creates a new zlib encoder with the specified compressionLevel, the specified windowBits, the specified memLevel, and the specified preset dictionary.
ZlibEncoder(ZlibWrapper wrapper)	Creates a new zlib encoder with the default compression level (6), default window bits (15), default memory level (8), and the specified wrapper.
ZlibEncoder(ZlibWrapper wrapper, int compressionLevel)	Creates a new zlib encoder with the specified compressionLevel, default window bits (15), default memory level (8), and the specified wrapper.
ZlibEncoder(ZlibWrapper wrapper, int compressionLevel, int windowBits, int memLevel)	Creates a new zlib encoder with the specified compressionLevel, the specified windowBits, the specified memLevel, and the specified wrapper.

Method Summary

Modifier and Type	Method	Description
void	afterAdd(ChannelHandlerContext ctx)
void	afterRemove(ChannelHandlerContext ctx)
void	beforeAdd(ChannelHandlerContext ctx)
void	beforeRemove(ChannelHandlerContext ctx)
ChannelFuture	close()
protected Object	encode(ChannelHandlerContext ctx, Channel channel, Object msg)	Transforms the specified message into another message and return the transformed message.
private ChannelFuture	finishEncode(ChannelHandlerContext ctx, ChannelEvent evt)
void	handleDownstream(ChannelHandlerContext ctx, ChannelEvent evt)	Handles the specified downstream event.
boolean	isClosed()

Methods inherited from class OneToOneStrictEncoder

doEncode

Methods inherited from class Object

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

Field Details

EMPTY_ARRAY

private static final byte[] EMPTY_ARRAY

wrapperOverhead

private final int wrapperOverhead

z

private final com.jcraft.jzlib.ZStream z

finished

private final AtomicBoolean finished

ctx

private volatile ChannelHandlerContext ctx

Constructor Details

ZlibEncoder

public ZlibEncoder()

Creates a new zlib encoder with the default compression level (6), default window bits (15), default memory level (8), and the default wrapper (ZlibWrapper.ZLIB).

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(int compressionLevel)

Creates a new zlib encoder with the specified compressionLevel, default window bits (15), default memory level (8), and the default wrapper (ZlibWrapper.ZLIB).

Parameters:

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

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(ZlibWrapper wrapper)

Creates a new zlib encoder with the default compression level (6), default window bits (15), default memory level (8), and the specified wrapper.

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(ZlibWrapper wrapper,
 int compressionLevel)

Creates a new zlib encoder with the specified compressionLevel, default window bits (15), default memory level (8), and the specified wrapper.

Parameters:

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

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(ZlibWrapper wrapper,
 int compressionLevel,
 int windowBits,
 int memLevel)

Creates a new zlib encoder with the specified compressionLevel, the specified windowBits, the specified memLevel, and the specified wrapper.

Parameters:

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

windowBits - The base two logarithm of the size of the history buffer. The value should be in the range 9 to 15 inclusive. Larger values result in better compression at the expense of memory usage. The default value is 15.

memLevel - How much memory should be allocated for the internal compression state. 1 uses minimum memory and 9 uses maximum memory. Larger values result in better and faster compression at the expense of memory usage. The default value is 8

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(byte[] dictionary)

Creates a new zlib encoder with the default compression level (6), default window bits (15), default memory level (8), and the specified preset dictionary. The wrapper is always ZlibWrapper.ZLIB because it is the only format that supports the preset dictionary.

Parameters:

dictionary - the preset dictionary

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(int compressionLevel,
 byte[] dictionary)

Creates a new zlib encoder with the specified compressionLevel, default window bits (15), default memory level (8), and the specified preset dictionary. The wrapper is always ZlibWrapper.ZLIB because it is the only format that supports the preset dictionary.

Parameters:

compressionLevel - 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

Throws:

CompressionException - if failed to initialize zlib

ZlibEncoder

public ZlibEncoder(int compressionLevel,
 int windowBits,
 int memLevel,
 byte[] dictionary)

Creates a new zlib encoder with the specified compressionLevel, the specified windowBits, the specified memLevel, and the specified preset dictionary. The wrapper is always ZlibWrapper.ZLIB because it is the only format that supports the preset dictionary.

Parameters:

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

windowBits - The base two logarithm of the size of the history buffer. The value should be in the range 9 to 15 inclusive. Larger values result in better compression at the expense of memory usage. The default value is 15.

memLevel - How much memory should be allocated for the internal compression state. 1 uses minimum memory and 9 uses maximum memory. Larger values result in better and faster compression at the expense of memory usage. The default value is 8

dictionary - the preset dictionary

Throws:

CompressionException - if failed to initialize zlib

Method Details

close

public ChannelFuture close()

isClosed

public boolean isClosed()

encode

protected Object encode(ChannelHandlerContext ctx,
 Channel channel,
 Object msg)
                 throws Exception

Description copied from class: OneToOneEncoder

Transforms the specified message into another message and return the transformed message. Note that you can not return null, unlike you can in OneToOneDecoder.decode(ChannelHandlerContext, Channel, Object); you must return something, at least ChannelBuffers.EMPTY_BUFFER.

Specified by:

encode in class OneToOneEncoder

Throws:

Exception

handleDownstream

public void handleDownstream(ChannelHandlerContext ctx,
 ChannelEvent evt)
                      throws Exception

Description copied from interface: ChannelDownstreamHandler

Handles the specified downstream event.

Specified by:

handleDownstream in interface ChannelDownstreamHandler

Overrides:

handleDownstream in class OneToOneEncoder

Parameters:

ctx - the context object for this handler

evt - the downstream event to process or intercept

Throws:

Exception

finishEncode

private ChannelFuture finishEncode(ChannelHandlerContext ctx,
 ChannelEvent evt)

beforeAdd

public void beforeAdd(ChannelHandlerContext ctx)
               throws Exception

Specified by:

beforeAdd in interface LifeCycleAwareChannelHandler

Throws:

Exception

afterAdd

public void afterAdd(ChannelHandlerContext ctx)
              throws Exception

Specified by:

afterAdd in interface LifeCycleAwareChannelHandler

Throws:

Exception

beforeRemove

public void beforeRemove(ChannelHandlerContext ctx)
                  throws Exception

Specified by:

beforeRemove in interface LifeCycleAwareChannelHandler

Throws:

Exception

afterRemove

public void afterRemove(ChannelHandlerContext ctx)
                 throws Exception

Specified by:

afterRemove in interface LifeCycleAwareChannelHandler

Throws:

Exception