Class Lz4FrameEncoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelOutboundHandlerAdapter

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

io.netty.handler.codec.compression.Lz4FrameEncoder

All Implemented Interfaces:

ChannelHandler, ChannelOutboundHandler

public class Lz4FrameEncoder
extends MessageToByteEncoder<ByteBuf>

Compresses a ByteBuf using the LZ4 format. See original LZ4 Github project and LZ4 block format for full description. Since the original LZ4 block format does not contains size of compressed block and size of original data this encoder uses format like LZ4 Java library written by Adrien Grand and approved by Yann Collet (author of original LZ4 library). * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Magic * Token * Compressed * Decompressed * Checksum * + * LZ4 compressed * * * * length * length * * * block * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Nested Class Summary

Nested classes/interfaces inherited from interface ChannelHandler

ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor	Description
Lz4FrameEncoder()	Creates the fastest LZ4 encoder with default block size (64 KB) and xxhash hashing for Java, based on Yann Collet's work available at Github.
Lz4FrameEncoder(boolean highCompressor)	Creates a new LZ4 encoder with hight or fast compression, default block size (64 KB) and xxhash hashing for Java, based on Yann Collet's work available at Github.
Lz4FrameEncoder(net.jpountz.lz4.LZ4Factory factory, boolean highCompressor, int blockSize, Checksum checksum)	Creates a new customizable LZ4 encoder.
Lz4FrameEncoder(net.jpountz.lz4.LZ4Factory factory, boolean highCompressor, int blockSize, Checksum checksum, int maxEncodeSize)	Creates a new customizable LZ4 encoder.

Method Summary

Modifier and Type	Method	Description
protected 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 Lz4FrameEncoder 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 Lz4FrameEncoder and so finish the encoding.
protected void	encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out)	Encode a message into a ByteBuf.
void	flush(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.flush() to forward to the next ChannelOutboundHandler in the ChannelPipeline.
void	handlerAdded(ChannelHandlerContext ctx)	Do nothing by default, sub-classes may override this method.
void	handlerRemoved(ChannelHandlerContext ctx)	Do nothing by default, sub-classes may override this method.
boolean	isClosed()	Returns true if and only if the compressed stream has been finished.

Methods inherited from class MessageToByteEncoder

acceptOutboundMessage, isPreferDirect, write

Methods inherited from class ChannelOutboundHandlerAdapter

bind, connect, deregister, disconnect, read

Methods inherited from class ChannelHandlerAdapter

ensureNotSharable, exceptionCaught, isSharable

Methods inherited from class Object

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

Methods inherited from interface ChannelHandler

exceptionCaught

Constructor Details

Lz4FrameEncoder

public Lz4FrameEncoder()

Creates the fastest LZ4 encoder with default block size (64 KB) and xxhash hashing for Java, based on Yann Collet's work available at Github.

Lz4FrameEncoder

public Lz4FrameEncoder(boolean highCompressor)

Creates a new LZ4 encoder with hight or fast compression, default block size (64 KB) and xxhash hashing for Java, based on Yann Collet's work available at Github.

Parameters:

highCompressor - if true codec will use compressor which requires more memory and is slower but compresses more efficiently

Lz4FrameEncoder

public Lz4FrameEncoder(net.jpountz.lz4.LZ4Factory factory,
 boolean highCompressor,
 int blockSize,
 Checksum checksum)

Creates a new customizable LZ4 encoder.

Parameters:

factory - user customizable LZ4Factory instance which may be JNI bindings to the original C implementation, a pure Java implementation or a Java implementation that uses the Unsafe

highCompressor - if true codec will use compressor which requires more memory and is slower but compresses more efficiently

blockSize - the maximum number of bytes to try to compress at once, must be >= 64 and invalid input: '<'= 32 M

checksum - the Checksum instance to use to check data for integrity

Lz4FrameEncoder

public Lz4FrameEncoder(net.jpountz.lz4.LZ4Factory factory,
 boolean highCompressor,
 int blockSize,
 Checksum checksum,
 int maxEncodeSize)

Creates a new customizable LZ4 encoder.

Parameters:

factory - user customizable LZ4Factory instance which may be JNI bindings to the original C implementation, a pure Java implementation or a Java implementation that uses the Unsafe

highCompressor - if true codec will use compressor which requires more memory and is slower but compresses more efficiently

blockSize - the maximum number of bytes to try to compress at once, must be >= 64 and invalid input: '<'= 32 M

checksum - the Checksum instance to use to check data for integrity

maxEncodeSize - the maximum size for an encode (compressed) buffer

Method Details

allocateBuffer

protected ByteBuf allocateBuffer(ChannelHandlerContext ctx,
 ByteBuf msg,
 boolean preferDirect)

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>

encode

protected void encode(ChannelHandlerContext ctx,
 ByteBuf in,
 ByteBuf out)
               throws Exception

Encode a message into a ByteBuf. This method will be called for each written message that can be handled by this encoder. Encodes the input buffer into blockSize chunks in the output buffer. Data is only compressed and written once we hit the blockSize; else, it is copied into the backing buffer to await more data.

Specified by:

encode in class MessageToByteEncoder<ByteBuf>

Parameters:

ctx - the ChannelHandlerContext which this MessageToByteEncoder belongs to

in - the message to encode

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

Throws:

Exception - is thrown if an error occurs

flush

public void flush(ChannelHandlerContext ctx)
           throws Exception

Description copied from class: ChannelOutboundHandlerAdapter

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

Specified by:

flush in interface ChannelOutboundHandler

Overrides:

flush in class ChannelOutboundHandlerAdapter

Parameters:

ctx - the ChannelHandlerContext for which the flush operation is made

Throws:

Exception - thrown if an error occurs

isClosed

public boolean isClosed()

Returns true if and only if the compressed stream has been finished.

close

public ChannelFuture close()

Close this Lz4FrameEncoder and so finish the encoding. The returned ChannelFuture will be notified once the operation completes.

close

public ChannelFuture close(ChannelPromise promise)

Close this Lz4FrameEncoder and so finish the encoding. The given ChannelFuture will be notified once the operation completes and will also be returned.

close

public void close(ChannelHandlerContext ctx,
 ChannelPromise promise)
           throws 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:

Exception - thrown if an error occurs

handlerAdded

public void handlerAdded(ChannelHandlerContext ctx)

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

handlerRemoved

public void handlerRemoved(ChannelHandlerContext ctx)
                    throws Exception

Description copied from class: ChannelHandlerAdapter

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

Specified by:

handlerRemoved in interface ChannelHandler

Overrides:

handlerRemoved in class ChannelHandlerAdapter

Throws:

Exception