Module io.netty5.codec

Package io.netty5.handler.codec

Class MessageToMessageCodec<INBOUND_IN,OUTBOUND_IN>

java.lang.Object

io.netty5.channel.ChannelHandlerAdapter

io.netty5.handler.codec.MessageToMessageCodec<INBOUND_IN,OUTBOUND_IN>

All Implemented Interfaces:

ChannelHandler

Direct Known Subclasses:

Http2StreamFrameToHttpObjectCodec, HttpContentEncoder

public abstract class MessageToMessageCodec<INBOUND_IN,OUTBOUND_IN>
extends ChannelHandlerAdapter

A Codec for on-the-fly encoding/decoding of message. This can be thought of as a combination of MessageToMessageDecoder and MessageToMessageEncoder. Here is an example of a MessageToMessageCodec which just decode from Integer to Long and encode from Long to Integer.

     public class NumberCodec extends
             MessageToMessageCodec<Integer, Long> {
         @Override
         public Long decode(ChannelHandlerContext ctx, Integer msg, List<Object> out)
                 throws Exception {
             out.add(msg.longValue());
         }

         @Override
         public Integer encode(ChannelHandlerContext ctx, Long msg, List<Object> out)
                 throws Exception {
             out.add(msg.intValue());
         }
     }
 

Be aware that you need to call ReferenceCounted.retain() on messages that are just passed through if they are of type ReferenceCounted. This is needed as the MessageToMessageCodec will call ReferenceCounted.release() on encoded / decoded messages.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MessageToMessageCodec()	Create a new instance which will try to detect the types to decode and encode out of the type parameter of the class.
protected	MessageToMessageCodec(Class<? extends INBOUND_IN> inboundMessageType, Class<? extends OUTBOUND_IN> outboundMessageType)	Create a new instance.

Method Summary

Modifier and Type	Method	Description
boolean	acceptInboundMessage(Object msg)	Returns true if and only if the specified message can be decoded by this codec.
boolean	acceptOutboundMessage(Object msg)	Returns true if and only if the specified message can be encoded by this codec.
void	channelRead(ChannelHandlerContext ctx, Object msg)	Invoked when the current Channel has read a message from the peer.
protected void	decode(ChannelHandlerContext ctx, INBOUND_IN msg)
protected void	decodeAndClose(ChannelHandlerContext ctx, INBOUND_IN msg)
protected void	encode(ChannelHandlerContext ctx, OUTBOUND_IN msg, List<Object> out)
protected void	encodeAndClose(ChannelHandlerContext ctx, OUTBOUND_IN msg, List<Object> out)
Future<Void>	write(ChannelHandlerContext ctx, Object msg)	Called once a write operation is made.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty5.channel.ChannelHandler

bind, channelActive, channelExceptionCaught, channelInactive, channelInboundEvent, channelReadComplete, channelRegistered, channelShutdown, channelUnregistered, channelWritabilityChanged, close, connect, deregister, disconnect, flush, handlerAdded, handlerRemoved, isSharable, pendingOutboundBytes, read, register, sendOutboundEvent, shutdown

Constructor Detail

MessageToMessageCodec

protected MessageToMessageCodec()

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

MessageToMessageCodec

protected MessageToMessageCodec(Class<? extends INBOUND_IN> inboundMessageType,
                                Class<? extends OUTBOUND_IN> outboundMessageType)

Create a new instance.

Parameters:

inboundMessageType - The type of messages to decode

outboundMessageType - The type of messages to encode

Method Detail

channelRead

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

Description copied from interface: ChannelHandler

Invoked when the current Channel has read a message from the peer.

Throws:

Exception

write

public Future<Void> write(ChannelHandlerContext ctx,
                          Object msg)

Description copied from interface: ChannelHandler

Called once a write operation is made. The write operation will write the messages through the ChannelPipeline. Those are then ready to be flushed to the actual Channel once Channel.flush() is called.

Parameters:

ctx - the ChannelHandlerContext for which the write operation is made

msg - the message to write

Returns:

the Future which will be notified once the operation completes.

acceptInboundMessage

public boolean acceptInboundMessage(Object msg)
                             throws Exception

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

Parameters:

msg - the message

Throws:

Exception

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

encode

protected void encode(ChannelHandlerContext ctx,
                      OUTBOUND_IN msg,
                      List<Object> out)
               throws Exception

Throws:

Exception

See Also:

MessageToMessageEncoder.encode(ChannelHandlerContext, Object, List)

encodeAndClose

protected void encodeAndClose(ChannelHandlerContext ctx,
                              OUTBOUND_IN msg,
                              List<Object> out)
                       throws Exception

Throws:

Exception

See Also:

MessageToMessageEncoder.encodeAndClose(ChannelHandlerContext, Object, List)

decode

protected void decode(ChannelHandlerContext ctx,
                      INBOUND_IN msg)
               throws Exception

Throws:

Exception

See Also:

MessageToMessageDecoder.decode(ChannelHandlerContext, Object)

decodeAndClose

protected void decodeAndClose(ChannelHandlerContext ctx,
                              INBOUND_IN msg)
                       throws Exception

Throws:

Exception

See Also:

MessageToMessageDecoder.decodeAndClose(ChannelHandlerContext, Object)