io.netty.handler.codec.protobuf

Class ProtobufDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelStateHandlerAdapter

io.netty.channel.ChannelInboundMessageHandlerAdapter<I>

io.netty.handler.codec.MessageToMessageDecoder<io.netty.buffer.ByteBuf>

io.netty.handler.codec.protobuf.ProtobufDecoder

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundMessageHandler<io.netty.buffer.ByteBuf>, io.netty.channel.ChannelStateHandler

@ChannelHandler.Sharable
public class ProtobufDecoder
extends MessageToMessageDecoder<io.netty.buffer.ByteBuf>

Decodes a received ByteBuf into a Google Protocol Buffers Message and MessageLite. Please note that this decoder must be used with a proper ByteToMessageDecoder 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, MyMessage req) {
     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

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields inherited from class io.netty.channel.ChannelInboundMessageHandlerAdapter

ABORT

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
protected Object	decode(io.netty.channel.ChannelHandlerContext ctx, io.netty.buffer.ByteBuf msg) Decode from one message to an other.

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

messageReceived

Methods inherited from class io.netty.channel.ChannelInboundMessageHandlerAdapter

acceptInboundMessage, beginMessageReceived, endMessageReceived, freeInboundBuffer, inboundBufferUpdated, newInboundBuffer

Methods inherited from class io.netty.channel.ChannelStateHandlerAdapter

channelActive, channelInactive, channelReadSuspended, channelRegistered, channelUnregistered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

afterAdd, afterRemove, beforeAdd, beforeRemove, 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, channelReadSuspended, 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

decode

protected Object decode(io.netty.channel.ChannelHandlerContext ctx,
            io.netty.buffer.ByteBuf msg)
                 throws Exception

Description copied from class: MessageToMessageDecoder

Decode from one message to an other. This method will be called till either the MessageBuf has nothing left or till this method returns null.

Specified by:

decode in class MessageToMessageDecoder<io.netty.buffer.ByteBuf>

Parameters:

ctx - the ChannelHandlerContext which this MessageToMessageDecoder belongs to

msg - the message to decode to an other one

Returns:

message the decoded message or null if more messages are needed be cause the implementation needs to do some kind of aggragation

Throws:

Exception - is thrown if an error accour