Package io.netty.handler.codec.protobuf

Class ProtobufEncoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelOutboundHandlerAdapter

io.netty.handler.codec.MessageToMessageEncoder<com.google.protobuf.MessageLiteOrBuilder>

io.netty.handler.codec.protobuf.ProtobufEncoder

All Implemented Interfaces:

ChannelHandler, ChannelOutboundHandler

@Sharable
public class ProtobufEncoder
extends MessageToMessageEncoder<com.google.protobuf.MessageLiteOrBuilder>

Encodes the requested Google Protocol Buffers Message and MessageLite into a ByteBuf. A typical setup for TCP/IP would be:

 ChannelPipeline pipeline = ...;

 // Decoders
 pipeline.addLast("frameDecoder",
                  new LengthFieldBasedFrameDecoder(1048576, 0, 4, 0, 4));
 pipeline.addLast("protobufDecoder",
                  new ProtobufDecoder(MyMessage.getDefaultInstance()));

 // Encoder
 pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
 pipeline.addLast("protobufEncoder", new ProtobufEncoder());
 

and then you can use a MyMessage instead of a ByteBuf as a message:

 void channelRead(ChannelHandlerContext ctx, Object msg) {
     MyMessage req = (MyMessage) msg;
     MyMessage res = MyMessage.newBuilder().setText(
                               "Did you say '" + req.getText() + "'?").build();
     ch.write(res);
 }
 

Nested Class Summary

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

ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor	Description
ProtobufEncoder()

Method Summary

Modifier and Type	Method	Description
protected void	encode(ChannelHandlerContext ctx, com.google.protobuf.MessageLiteOrBuilder msg, List<Object> out)	Encode from one message to an other.

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

acceptOutboundMessage, 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

Constructor Details

ProtobufEncoder

public ProtobufEncoder()

Method Details

encode

protected void encode(ChannelHandlerContext ctx,
 com.google.protobuf.MessageLiteOrBuilder msg,
 List<Object> out)
               throws Exception

Description copied from class: MessageToMessageEncoder

Encode from one message to an other. This method will be called for each written message that can be handled by this encoder.

Specified by:

encode in class MessageToMessageEncoder<com.google.protobuf.MessageLiteOrBuilder>

Parameters:

ctx - the ChannelHandlerContext which this MessageToMessageEncoder belongs to

msg - the message to encode to an other one

out - the List into which the encoded msg should be added needs to do some kind of aggregation

Throws:

Exception - is thrown if an error occurs