Package io.netty.handler.codec

Class ByteToMessageCodec<I>

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.ChannelDuplexHandler

io.netty.handler.codec.ByteToMessageCodec<I>

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler, ChannelOutboundHandler

public abstract class ByteToMessageCodec<I>
extends ChannelDuplexHandler

A Codec for on-the-fly encoding/decoding of bytes to messages and vise-versa. This can be thought of as a combination of ByteToMessageDecoder and MessageToByteEncoder. Be aware that sub-classes of ByteToMessageCodec MUST NOT annotated with

invalid @link

{@link @Sharable

}.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private final class	ByteToMessageCodec.Encoder

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

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private final ByteToMessageDecoder	decoder
private final MessageToByteEncoder<I>	encoder
private final TypeParameterMatcher	outboundMsgMatcher

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ByteToMessageCodec()	see ByteToMessageCodec(boolean) with true as boolean parameter.
protected	ByteToMessageCodec(boolean preferDirect)	Create a new instance which will try to detect the types to match out of the type parameter of the class.
protected	ByteToMessageCodec(Class<? extends I> outboundMessageType)	see ByteToMessageCodec(Class, boolean) with true as boolean value.
protected	ByteToMessageCodec(Class<? extends I> outboundMessageType, boolean preferDirect)	Create a new instance

Method Summary

Modifier and Type	Method	Description
boolean	acceptOutboundMessage(Object msg)	Returns true if and only if the specified message can be encoded by this codec.
void	channelInactive(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelInactive() to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelRead(ChannelHandlerContext ctx, Object msg)	Calls ChannelHandlerContext.fireChannelRead(Object) to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelReadComplete(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelReadComplete() to forward to the next ChannelInboundHandler in the ChannelPipeline.
protected abstract void	decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out)
protected void	decodeLast(ChannelHandlerContext ctx, ByteBuf in, List<Object> out)
protected abstract void	encode(ChannelHandlerContext ctx, I msg, ByteBuf out)
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.
void	write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)	Calls ChannelOutboundInvoker.write(Object, ChannelPromise) to forward to the next ChannelOutboundHandler in the ChannelPipeline.

Methods inherited from class io.netty.channel.ChannelDuplexHandler

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

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, isSharable

Methods inherited from class java.lang.Object

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

Field Details

outboundMsgMatcher

private final TypeParameterMatcher outboundMsgMatcher

encoder

private final MessageToByteEncoder<I> encoder

decoder

private final ByteToMessageDecoder decoder

Constructor Details

ByteToMessageCodec

protected ByteToMessageCodec()

see ByteToMessageCodec(boolean) with true as boolean parameter.

ByteToMessageCodec

protected ByteToMessageCodec(Class<? extends I> outboundMessageType)

see ByteToMessageCodec(Class, boolean) with true as boolean value.

ByteToMessageCodec

protected ByteToMessageCodec(boolean preferDirect)

Create a new instance which will try to detect the types to match out of the type parameter of the class.

Parameters:

preferDirect - true if a direct ByteBuf should be tried to be used as target for the encoded messages. If false is used it will allocate a heap ByteBuf, which is backed by an byte array.

ByteToMessageCodec

protected ByteToMessageCodec(Class<? extends I> outboundMessageType,
 boolean preferDirect)

Create a new instance

Parameters:

outboundMessageType - The type of messages to match

preferDirect - true if a direct ByteBuf should be tried to be used as target for the encoded messages. If false is used it will allocate a heap ByteBuf, which is backed by an byte array.

Method Details

acceptOutboundMessage

public boolean acceptOutboundMessage(Object msg)
                              throws Exception

Returns true if and only if the specified message can be encoded by this codec.

Parameters:

msg - the message

Throws:

Exception

channelRead

public void channelRead(ChannelHandlerContext ctx,
 Object msg)
                 throws Exception

Description copied from class: ChannelInboundHandlerAdapter

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

Specified by:

channelRead in interface ChannelInboundHandler

Overrides:

channelRead in class ChannelInboundHandlerAdapter

Throws:

Exception

write

public void write(ChannelHandlerContext ctx,
 Object msg,
 ChannelPromise promise)
           throws Exception

Description copied from class: ChannelDuplexHandler

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

Specified by:

write in interface ChannelOutboundHandler

Overrides:

write in class ChannelDuplexHandler

Parameters:

ctx - the ChannelHandlerContext for which the write operation is made

msg - the message to write

promise - the ChannelPromise to notify once the operation completes

Throws:

Exception - thrown if an error occurs

channelReadComplete

public void channelReadComplete(ChannelHandlerContext ctx)
                         throws Exception

Description copied from class: ChannelInboundHandlerAdapter

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

Specified by:

channelReadComplete in interface ChannelInboundHandler

Overrides:

channelReadComplete in class ChannelInboundHandlerAdapter

Throws:

Exception

channelInactive

public void channelInactive(ChannelHandlerContext ctx)
                     throws Exception

Description copied from class: ChannelInboundHandlerAdapter

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

Specified by:

channelInactive in interface ChannelInboundHandler

Overrides:

channelInactive in class ChannelInboundHandlerAdapter

Throws:

Exception

handlerAdded

public void handlerAdded(ChannelHandlerContext ctx)
                  throws 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:

Exception

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

encode

protected abstract void encode(ChannelHandlerContext ctx,
 I msg,
 ByteBuf out)
                        throws Exception

Throws:

Exception

See Also:

• MessageToByteEncoder.encode(ChannelHandlerContext, Object, ByteBuf)

decode

protected abstract void decode(ChannelHandlerContext ctx,
 ByteBuf in,
 List<Object> out)
                        throws Exception

Throws:

Exception

See Also:

• ByteToMessageDecoder.decode(ChannelHandlerContext, ByteBuf, List)

decodeLast

protected void decodeLast(ChannelHandlerContext ctx,
 ByteBuf in,
 List<Object> out)
                   throws Exception

Throws:

Exception

See Also:

• ByteToMessageDecoder.decodeLast(ChannelHandlerContext, ByteBuf, List)