Package io.netty.handler.codec.compression

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 io.netty.channel.ChannelHandler

ChannelHandler.Sharable

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 ByteBuf	allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect)	Allocate a ByteBuf which will be used as argument of #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.
protected void	encode(ChannelHandlerContext ctx, ByteBuf uncompressed, ByteBuf out)	Encode a message into a ByteBuf.
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 io.netty.handler.codec.MessageToByteEncoder

acceptOutboundMessage, isPreferDirect, write

Methods inherited from class io.netty.channel.ChannelOutboundHandlerAdapter

bind, connect, deregister, disconnect, flush, read

Methods inherited from class io.netty.channel.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 io.netty.channel.ChannelHandler

exceptionCaught, handlerRemoved

Constructor Detail

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 Detail

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

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

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 #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

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