Class JdkZlibEncoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelOutboundHandlerAdapter

io.netty.handler.codec.MessageToByteEncoder<ByteBuf>

io.netty.handler.codec.compression.ZlibEncoder

io.netty.handler.codec.compression.JdkZlibEncoder

All Implemented Interfaces:

ChannelHandler, ChannelOutboundHandler

public class JdkZlibEncoder
extends ZlibEncoder

Compresses a ByteBuf 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 final java.util.zip.CRC32	crc
private ChannelHandlerContext	ctx
private final java.util.zip.Deflater	deflater
private boolean	finished
private static final byte[]	gzipHeader
private static final InternalLogger	logger
private static final int	MAX_INITIAL_OUTPUT_BUFFER_SIZE	Maximum initial size for temporary heap buffers used for the compressed output.
private static final int	MAX_INPUT_BUFFER_SIZE	Max size for temporary heap buffers used to copy input data to heap.
private final ZlibWrapper	wrapper
private boolean	writeHeader

Constructor Summary

Constructors

Constructor	Description
JdkZlibEncoder()	Creates a new zlib encoder with a compression level of (6) and the default wrapper (ZlibWrapper.ZLIB).
JdkZlibEncoder(byte[] dictionary)	Creates a new zlib encoder with a compression level of (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 a compression level of (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
protected final ByteBuf	allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect)	Allocate a ByteBuf which will be used as argument of MessageToByteEncoder.encode(ChannelHandlerContext, I, ByteBuf).
ChannelFuture	close()	Close this ZlibEncoder and so finish the encoding.
void	close(ChannelHandlerContext ctx, ChannelPromise promise)	Calls ChannelOutboundInvoker.close(ChannelPromise) to forward to the next ChannelOutboundHandler in the ChannelPipeline.
ChannelFuture	close(ChannelPromise promise)	Close this ZlibEncoder and so finish the encoding.
private ChannelHandlerContext	ctx()
private void	deflate(ByteBuf out)
protected void	encode(ChannelHandlerContext ctx, ByteBuf uncompressed, ByteBuf out)	Encode a message into a ByteBuf.
private void	encodeSome(ByteBuf in, ByteBuf out)
private ChannelFuture	finishEncode(ChannelHandlerContext ctx, ChannelPromise promise)
void	handlerAdded(ChannelHandlerContext ctx)	Do nothing by default, sub-classes may override this method.
boolean	isClosed()	Returns true if and only if the end of the compressed stream has been reached.

Methods inherited from class MessageToByteEncoder

acceptOutboundMessage, isPreferDirect, write

Methods inherited from class ChannelOutboundHandlerAdapter

bind, connect, deregister, disconnect, flush, read

Methods inherited from class ChannelHandlerAdapter

ensureNotSharable, exceptionCaught, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

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

Methods inherited from interface ChannelHandler

exceptionCaught, handlerRemoved

Field Details

logger

private static final InternalLogger logger

MAX_INITIAL_OUTPUT_BUFFER_SIZE

private static final int MAX_INITIAL_OUTPUT_BUFFER_SIZE

Maximum initial size for temporary heap buffers used for the compressed output. Buffer may still grow beyond this if necessary.

MAX_INPUT_BUFFER_SIZE

private static final int MAX_INPUT_BUFFER_SIZE

Max size for temporary heap buffers used to copy input data to heap.

wrapper

private final ZlibWrapper wrapper

deflater

private final java.util.zip.Deflater deflater

finished

private volatile boolean finished

ctx

private volatile ChannelHandlerContext ctx

crc

private final java.util.zip.CRC32 crc

gzipHeader

private static final byte[] gzipHeader

writeHeader

private boolean writeHeader

Constructor Details

JdkZlibEncoder

public JdkZlibEncoder()

Creates a new zlib encoder with a compression level of (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 a compression level of (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 can be set as -1 which correlates to the underlying Deflater.DEFAULT_COMPRESSION level.

Throws:

CompressionException - if failed to initialize zlib

JdkZlibEncoder

public JdkZlibEncoder(byte[] dictionary)

Creates a new zlib encoder with a compression level of (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 can be set as -1 which correlates to the underlying Deflater.DEFAULT_COMPRESSION level.

dictionary - the preset dictionary

Throws:

CompressionException - if failed to initialize zlib

Method Details

close

public ChannelFuture close()

Description copied from class: ZlibEncoder

Close this ZlibEncoder and so finish the encoding. The returned ChannelFuture will be notified once the operation completes.

Specified by:

close in class ZlibEncoder

close

public ChannelFuture close(ChannelPromise promise)

Description copied from class: ZlibEncoder

Close this ZlibEncoder and so finish the encoding. The given ChannelFuture will be notified once the operation completes and will also be returned.

Specified by:

close in class ZlibEncoder

ctx

private ChannelHandlerContext ctx()

isClosed

public boolean isClosed()

Description copied from class: ZlibEncoder

Returns true if and only if the end of the compressed stream has been reached.

Specified by:

isClosed in class ZlibEncoder

encode

protected void encode(ChannelHandlerContext ctx,
 ByteBuf uncompressed,
 ByteBuf out)
               throws java.lang.Exception

Description copied from class: MessageToByteEncoder

Encode a message into a ByteBuf. This method will be called for each written message that can be handled by this encoder.

Specified by:

encode in class MessageToByteEncoder<ByteBuf>

Parameters:

ctx - the ChannelHandlerContext which this MessageToByteEncoder belongs to

uncompressed - the message to encode

out - the ByteBuf into which the encoded message will be written

Throws:

java.lang.Exception - is thrown if an error occurs

encodeSome

private void encodeSome(ByteBuf in,
 ByteBuf out)

allocateBuffer

protected final ByteBuf allocateBuffer(ChannelHandlerContext ctx,
 ByteBuf msg,
 boolean preferDirect)
                                throws java.lang.Exception

Description copied from class: MessageToByteEncoder

Allocate a ByteBuf which will be used as argument of MessageToByteEncoder.encode(ChannelHandlerContext, I, ByteBuf). Sub-classes may override this method to return ByteBuf with a perfect matching initialCapacity.

Overrides:

allocateBuffer in class MessageToByteEncoder<ByteBuf>

Throws:

java.lang.Exception

close

public void close(ChannelHandlerContext ctx,
 ChannelPromise promise)
           throws java.lang.Exception

Description copied from class: ChannelOutboundHandlerAdapter

Calls ChannelOutboundInvoker.close(ChannelPromise) to forward to the next ChannelOutboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Specified by:

close in interface ChannelOutboundHandler

Overrides:

close in class ChannelOutboundHandlerAdapter

Parameters:

ctx - the ChannelHandlerContext for which the close operation is made

promise - the ChannelPromise to notify once the operation completes

Throws:

java.lang.Exception - thrown if an error occurs

finishEncode

private ChannelFuture finishEncode(ChannelHandlerContext ctx,
 ChannelPromise promise)

deflate

private void deflate(ByteBuf out)

handlerAdded

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

Description copied from class: ChannelHandlerAdapter

Do nothing by default, sub-classes may override this method.

Specified by:

handlerAdded in interface ChannelHandler

Overrides:

handlerAdded in class ChannelHandlerAdapter

Throws:

java.lang.Exception