Package io.netty.handler.codec.compression

Class SnappyFrameEncoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelOutboundHandlerAdapter

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

io.netty.handler.codec.compression.SnappyFrameEncoder

All Implemented Interfaces:

ChannelHandler, ChannelOutboundHandler

Direct Known Subclasses:

SnappyFramedEncoder

public class SnappyFrameEncoder
extends MessageToByteEncoder<ByteBuf>

Compresses a ByteBuf using the Snappy framing format. See Snappy framing format.

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private static int	MIN_COMPRESSIBLE_LENGTH	The minimum amount that we'll consider actually attempting to compress.
private int	sliceSize
private Snappy	snappy
private static int	SNAPPY_SLICE_JUMBO_SIZE	Both 32767 and 65535 are valid lengths for the Snappy framing format
private static short	SNAPPY_SLICE_SIZE
private boolean	started
private static byte[]	STREAM_START	All streams should start with the "Stream identifier", containing chunk type 0xff, a length field of 0x6, and 'sNaPpY' in ASCII.

Constructor Summary

Constructors

Modifier	Constructor	Description
	SnappyFrameEncoder()
private	SnappyFrameEncoder(int sliceSize)

Method Summary

Modifier and Type	Method	Description
private static void	calculateAndWriteChecksum(ByteBuf slice, ByteBuf out)	Calculates and writes the 4-byte checksum to the output buffer
protected void	encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out)	Encode a message into a ByteBuf.
private static void	setChunkLength(ByteBuf out, int lengthIdx)
static SnappyFrameEncoder	snappyEncoderWithJumboFrames()	Create a new instance with a 65535 chunk size.
private static void	writeChunkLength(ByteBuf out, int chunkLength)	Writes the 2-byte chunk length to the output buffer.
private static void	writeUnencodedChunk(ByteBuf in, ByteBuf out, int dataLength)

Methods inherited from class io.netty.handler.codec.MessageToByteEncoder

acceptOutboundMessage, allocateBuffer, isPreferDirect, write

Methods inherited from class io.netty.channel.ChannelOutboundHandlerAdapter

bind, close, connect, deregister, disconnect, flush, read

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, exceptionCaught, handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

exceptionCaught, handlerAdded, handlerRemoved

Field Detail

SNAPPY_SLICE_SIZE

private static final short SNAPPY_SLICE_SIZE

See Also:

Constant Field Values

SNAPPY_SLICE_JUMBO_SIZE

private static final int SNAPPY_SLICE_JUMBO_SIZE

Both 32767 and 65535 are valid lengths for the Snappy framing format

See Also:

Constant Field Values

MIN_COMPRESSIBLE_LENGTH

private static final int MIN_COMPRESSIBLE_LENGTH

The minimum amount that we'll consider actually attempting to compress. This value is preamble + the minimum length our Snappy service will compress (instead of just emitting a literal).

See Also:

Constant Field Values

STREAM_START

private static final byte[] STREAM_START

All streams should start with the "Stream identifier", containing chunk type 0xff, a length field of 0x6, and 'sNaPpY' in ASCII.

snappy

private final Snappy snappy

started

private boolean started

sliceSize

private final int sliceSize

Constructor Detail

SnappyFrameEncoder

public SnappyFrameEncoder()

SnappyFrameEncoder

private SnappyFrameEncoder(int sliceSize)

Method Detail

snappyEncoderWithJumboFrames

public static SnappyFrameEncoder snappyEncoderWithJumboFrames()

Create a new instance with a 65535 chunk size.

encode

protected void encode(ChannelHandlerContext ctx,
                      ByteBuf in,
                      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

in - 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

writeUnencodedChunk

private static void writeUnencodedChunk(ByteBuf in,
                                        ByteBuf out,
                                        int dataLength)

setChunkLength

private static void setChunkLength(ByteBuf out,
                                   int lengthIdx)

writeChunkLength

private static void writeChunkLength(ByteBuf out,
                                     int chunkLength)

Writes the 2-byte chunk length to the output buffer.

Parameters:

out - The buffer to write to

chunkLength - The length to write

calculateAndWriteChecksum

private static void calculateAndWriteChecksum(ByteBuf slice,
                                              ByteBuf out)

Calculates and writes the 4-byte checksum to the output buffer

Parameters:

slice - The data to calculate the checksum for

out - The output buffer to write the checksum to