io.netty.handler.codec.protobuf

Class ProtobufDecoder

java.lang.Object

io.netty.channel.ChannelStateHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.handler.codec.MessageToMessageDecoder<ByteBuf,com.google.protobuf.MessageLite>

io.netty.handler.codec.protobuf.ProtobufDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler, ChannelInboundMessageHandler<ByteBuf>, ChannelStateHandler

@ChannelHandler.Sharable
public class ProtobufDecoder
extends MessageToMessageDecoder<ByteBuf,com.google.protobuf.MessageLite>

Decodes a received ByteBuf into a Google Protocol Buffers Message and MessageLite. Please note that this decoder must be used with a proper FrameDecoder such as ProtobufVarint32FrameDecoder or LengthFieldBasedFrameDecoder if you are using a stream-based transport such as TCP/IP. 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 messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
     MyMessage req = (MyMessage) e.getMessage();
     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 and Description
ProtobufDecoder(com.google.protobuf.MessageLite prototype) Creates a new instance.
ProtobufDecoder(com.google.protobuf.MessageLite prototype, com.google.protobuf.ExtensionRegistry extensionRegistry)

Method Summary

Methods

Modifier and Type	Method and Description
com.google.protobuf.MessageLite	decode(ChannelHandlerContext ctx, ByteBuf msg)
boolean	isDecodable(Object msg) Returns true if and only if the specified message can be decoded by this decoder.

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

inboundBufferUpdated, newInboundBuffer

Methods inherited from class io.netty.channel.ChannelStateHandlerAdapter

afterAdd, afterRemove, beforeAdd, beforeRemove, channelActive, channelInactive, channelRegistered, channelUnregistered, exceptionCaught, userEventTriggered

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.ChannelStateHandler

channelActive, channelInactive, channelRegistered, channelUnregistered

Methods inherited from interface io.netty.channel.ChannelHandler

afterAdd, afterRemove, beforeAdd, beforeRemove, exceptionCaught, userEventTriggered

Constructor Detail

ProtobufDecoder

public ProtobufDecoder(com.google.protobuf.MessageLite prototype)

Creates a new instance.

ProtobufDecoder

public ProtobufDecoder(com.google.protobuf.MessageLite prototype,
               com.google.protobuf.ExtensionRegistry extensionRegistry)

Method Detail

isDecodable

public boolean isDecodable(Object msg)
                    throws Exception

Description copied from class: MessageToMessageDecoder

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

Overrides:

isDecodable in class MessageToMessageDecoder<ByteBuf,com.google.protobuf.MessageLite>

Parameters:

msg - the message

Throws:

Exception

decode

public com.google.protobuf.MessageLite decode(ChannelHandlerContext ctx,
                                     ByteBuf msg)
                                       throws Exception

Specified by:

decode in class MessageToMessageDecoder<ByteBuf,com.google.protobuf.MessageLite>

Throws:

Exception