io.netty.handler.codec.protobuf

Class ProtobufDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

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

io.netty.handler.codec.protobuf.ProtobufDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler

@ChannelHandler.Sharable
public class ProtobufDecoder
extends MessageToMessageDecoder<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 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 and Description
ProtobufDecoder(com.google.protobuf.MessageLite prototype) Creates a new instance.
ProtobufDecoder(com.google.protobuf.MessageLite prototype, com.google.protobuf.ExtensionRegistry extensionRegistry)
ProtobufDecoder(com.google.protobuf.MessageLite prototype, com.google.protobuf.ExtensionRegistryLite extensionRegistry)

Method Summary

Modifier and Type	Method and Description
protected void	decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) Decode from one message to an other.

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

acceptInboundMessage, channelRead, channelReadComplete

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, 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

handlerAdded, handlerRemoved

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)

ProtobufDecoder

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

Method Detail

decode

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

Description copied from class: MessageToMessageDecoder

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

Specified by:

decode in class MessageToMessageDecoder<ByteBuf>

Parameters:

ctx - the ChannelHandlerContext which this MessageToMessageDecoder belongs to

msg - the message to decode to an other one

out - the List to which decoded messages should be added

Throws:

Exception - is thrown if an error occurs