Package org.jboss.netty.handler.codec.compression

Class JdkZlibEncoder

java.lang.Object

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

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

org.jboss.netty.handler.codec.compression.JdkZlibEncoder

All Implemented Interfaces:

ChannelDownstreamHandler, ChannelHandler, LifeCycleAwareChannelHandler

public class JdkZlibEncoder
extends OneToOneStrictEncoder
implements LifeCycleAwareChannelHandler

Compresses a ChannelBuffer using the deflate algorithm.

Nested Class Summary

Nested classes/interfaces inherited from interface org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.zip.CRC32	crc
private ChannelHandlerContext	ctx
private java.util.zip.Deflater	deflater
private java.util.concurrent.atomic.AtomicBoolean	finished
private static byte[]	gzipHeader
private byte[]	out
private ZlibWrapper	wrapper
private boolean	writeHeader

Constructor Summary

Constructors

Constructor	Description
JdkZlibEncoder()	Creates a new zlib encoder with the default compression level (6) and the default wrapper (ZlibWrapper.ZLIB).
JdkZlibEncoder(byte[] dictionary)	Creates a new zlib encoder with the default compression level (6) and the specified preset dictionary.
JdkZlibEncoder(int compressionLevel)	Creates a new zlib encoder with the specified compressionLevel and the default wrapper (ZlibWrapper.ZLIB).
JdkZlibEncoder(int compressionLevel, byte[] dictionary)	Creates a new zlib encoder with the specified compressionLevel and the specified preset dictionary.
JdkZlibEncoder(ZlibWrapper wrapper)	Creates a new zlib encoder with the default compression level (6) and the specified wrapper.
JdkZlibEncoder(ZlibWrapper wrapper, int compressionLevel)	Creates a new zlib encoder with the specified compressionLevel 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()
private void	deflate(ChannelBuffer out)
protected java.lang.Object	encode(ChannelHandlerContext ctx, Channel channel, java.lang.Object msg)	Transforms the specified message into another message and return the transformed message.
private int	estimateCompressedSize(int originalSize)
private ChannelFuture	finishEncode(ChannelHandlerContext ctx, ChannelEvent evt)
void	handleDownstream(ChannelHandlerContext ctx, ChannelEvent evt)	Handles the specified downstream event.
boolean	isClosed()
private boolean	isGzip()

Methods inherited from class org.jboss.netty.handler.codec.oneone.OneToOneStrictEncoder

doEncode

Methods inherited from class java.lang.Object

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

Field Detail

wrapper

private final ZlibWrapper wrapper

deflater

private final java.util.zip.Deflater deflater

finished

private final java.util.concurrent.atomic.AtomicBoolean finished

ctx

private volatile ChannelHandlerContext ctx

out

private byte[] out

crc

private final java.util.zip.CRC32 crc

gzipHeader

private static final byte[] gzipHeader

writeHeader

private boolean writeHeader

Constructor Detail

JdkZlibEncoder

public JdkZlibEncoder()

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

Throws:

CompressionException - if failed to initialize zlib

JdkZlibEncoder

public JdkZlibEncoder(int compressionLevel)

Creates a new zlib encoder with the specified compressionLevel 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

JdkZlibEncoder

public JdkZlibEncoder(ZlibWrapper wrapper)

Creates a new zlib encoder with the default compression level (6) and the specified wrapper.

Throws:

CompressionException - if failed to initialize zlib

JdkZlibEncoder

public JdkZlibEncoder(ZlibWrapper wrapper,
                      int compressionLevel)

Creates a new zlib encoder with the specified compressionLevel 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

JdkZlibEncoder

public JdkZlibEncoder(byte[] dictionary)

Creates a new zlib encoder with the default compression level (6) 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

JdkZlibEncoder

public JdkZlibEncoder(int compressionLevel,
                      byte[] dictionary)

Creates a new zlib encoder with the specified compressionLevel 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

Method Detail

close

public ChannelFuture close()

isGzip

private boolean isGzip()

isClosed

public boolean isClosed()

encode

protected java.lang.Object encode(ChannelHandlerContext ctx,
                                  Channel channel,
                                  java.lang.Object msg)
                           throws java.lang.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:

java.lang.Exception

estimateCompressedSize

private int estimateCompressedSize(int originalSize)

handleDownstream

public void handleDownstream(ChannelHandlerContext ctx,
                             ChannelEvent evt)
                      throws java.lang.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:

java.lang.Exception

finishEncode

private ChannelFuture finishEncode(ChannelHandlerContext ctx,
                                   ChannelEvent evt)

deflate

private void deflate(ChannelBuffer out)

beforeAdd

public void beforeAdd(ChannelHandlerContext ctx)
               throws java.lang.Exception

Specified by:

beforeAdd in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception

afterAdd

public void afterAdd(ChannelHandlerContext ctx)
              throws java.lang.Exception

Specified by:

afterAdd in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception

beforeRemove

public void beforeRemove(ChannelHandlerContext ctx)
                  throws java.lang.Exception

Specified by:

beforeRemove in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception

afterRemove

public void afterRemove(ChannelHandlerContext ctx)
                 throws java.lang.Exception

Specified by:

afterRemove in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception