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 io.netty.channel.ChannelHandler
  ChannelHandler.Sharable

Field Summary

Fields
Modifier and Type	Field and Description
`private int`	`blockSize`
`private ByteBuf`	`buffer` Inner byte buffer for outgoing data.
`private ByteBufChecksum`	`checksum` Underlying checksum calculator in use.
`private int`	`compressionLevel` Compression level of current LZ4 encoder (depends on `blockSize`).
`private net.jpountz.lz4.LZ4Compressor`	`compressor` Underlying compressor in use.
`private ChannelHandlerContext`	`ctx` Used to interact with its `ChannelPipeline` and other handlers.
`(package private) static int`	`DEFAULT_MAX_ENCODE_SIZE`
`private static EncoderException`	`ENCODE_FINSHED_EXCEPTION`
`private boolean`	`finished` Indicates if the compressed stream has been finished.
`private int`	`maxEncodeSize` Maximum size for any buffer to write encoded (compressed) data into.

Constructor Summary

Constructors
Constructor and 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, java.util.zip.Checksum checksum)` Creates a new customizable LZ4 encoder.
`Lz4FrameEncoder(net.jpountz.lz4.LZ4Factory factory, boolean highCompressor, int blockSize, java.util.zip.Checksum checksum, int maxEncodeSize)` Creates a new customizable LZ4 encoder.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected ByteBuf`	`allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect)` Allocate a `ByteBuf` which will be used as argument of `#encode(ChannelHandlerContext, I, ByteBuf)`.
`private ByteBuf`	`allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect, boolean allowEmptyReturn)`
`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.
`private static int`	`compressionLevel(int blockSize)` Calculates compression level on the basis of block size.
`private ChannelHandlerContext`	`ctx()`
`protected void`	`encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out)` Encode a message into a `ByteBuf`.
`private ChannelFuture`	`finishEncode(ChannelHandlerContext ctx, ChannelPromise promise)`
`void`	`flush(ChannelHandlerContext ctx)` Calls `ChannelHandlerContext.flush()` to forward to the next `ChannelOutboundHandler` in the `ChannelPipeline`.
`private void`	`flushBufferedData(ByteBuf out)`
`(package private) ByteBuf`	`getBackingBuffer()`
`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 io.netty.handler.codec.MessageToByteEncoder
acceptOutboundMessage, isPreferDirect, write

Methods inherited from class io.netty.channel.ChannelOutboundHandlerAdapter
bind, connect, deregister, disconnect, read

Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, exceptionCaught, 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

- Field Detail
  - ENCODE_FINSHED_EXCEPTION
```
private static final EncoderException ENCODE_FINSHED_EXCEPTION
```
  - DEFAULT_MAX_ENCODE_SIZE
```
static final int DEFAULT_MAX_ENCODE_SIZE
```
    See Also:
    
    Constant Field Values
  - blockSize
```
private final int blockSize
```
  - compressor
```
private final net.jpountz.lz4.LZ4Compressor compressor
```
    Underlying compressor in use.
  - checksum
```
private final ByteBufChecksum checksum
```
    Underlying checksum calculator in use.
  - compressionLevel
```
private final int compressionLevel
```
    Compression level of current LZ4 encoder (depends on blockSize).
  - buffer
```
private ByteBuf buffer
```
    Inner byte buffer for outgoing data. It's capacity will be blockSize.
  - maxEncodeSize
```
private final int maxEncodeSize
```
    Maximum size for any buffer to write encoded (compressed) data into.
  - finished
```
private volatile boolean finished
```
    Indicates if the compressed stream has been finished.
  - ctx
```
private volatile ChannelHandlerContext ctx
```
    Used to interact with its ChannelPipeline and other handlers.
- Constructor Detail
  - 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,
                       java.util.zip.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 <= 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,
                       java.util.zip.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 <= 32 M
    
    checksum - the Checksum instance to use to check data for integrity
    
    maxEncodeSize - the maximum size for an encode (compressed) buffer
- Method Detail
  - compressionLevel
```
private static int compressionLevel(int blockSize)
```
    Calculates compression level on the basis of block size.
  - 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 #encode(ChannelHandlerContext, I, ByteBuf). Sub-classes may override this method to return ByteBuf with a perfect matching initialCapacity.
    
    Overrides:
    
    allocateBuffer in class MessageToByteEncoder<ByteBuf>
  - allocateBuffer
```
private ByteBuf allocateBuffer(ChannelHandlerContext ctx,
                               ByteBuf msg,
                               boolean preferDirect,
                               boolean allowEmptyReturn)
```
  - encode
```
protected void encode(ChannelHandlerContext ctx,
                      ByteBuf in,
                      ByteBuf out)
               throws java.lang.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:
    
    java.lang.Exception - is thrown if an error occurs
  - flushBufferedData
```
private void flushBufferedData(ByteBuf out)
```
  - flush
```
public void flush(ChannelHandlerContext ctx)
           throws java.lang.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:
    
    java.lang.Exception - thrown if an error occurs
  - finishEncode
```
private ChannelFuture finishEncode(ChannelHandlerContext ctx,
                                   ChannelPromise promise)
```
  - 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 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
  - ctx
```
private ChannelHandlerContext ctx()
```
  - 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 java.lang.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:
    
    java.lang.Exception
  - getBackingBuffer
```
final ByteBuf getBackingBuffer()
```

Class Lz4FrameEncoder

Nested Class Summary

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

Field Summary

Constructor Summary

Method Summary

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

Methods inherited from class io.netty.channel.ChannelOutboundHandlerAdapter

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

Methods inherited from class java.lang.Object

Methods inherited from interface io.netty.channel.ChannelHandler

Field Detail

ENCODE_FINSHED_EXCEPTION

DEFAULT_MAX_ENCODE_SIZE

blockSize

compressor

checksum

compressionLevel

buffer

maxEncodeSize

finished

ctx

Constructor Detail

Lz4FrameEncoder

Lz4FrameEncoder

Lz4FrameEncoder

Lz4FrameEncoder

Method Detail

compressionLevel

allocateBuffer

allocateBuffer

encode

flushBufferedData

flush

finishEncode

isClosed

close

close

close

ctx

handlerAdded

handlerRemoved

getBackingBuffer