org.jboss.netty.handler.codec.protobuf
Class ProtobufDecoder

java.lang.Object
  org.jboss.netty.handler.codec.oneone.OneToOneDecoder
      org.jboss.netty.handler.codec.protobuf.ProtobufDecoder

All Implemented Interfaces:

ChannelHandler, ChannelUpstreamHandler

@ChannelHandler.Sharable
public class ProtobufDecoder
extends OneToOneDecoder

Decodes a received ChannelBuffer 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 ChannelBuffer 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);
 }
 

Version:

$Rev:231 $, $Date:2008-06-12 16:44:50 +0900 (목, 12 6월 2008) $

Author:

The Netty Project, Trustin Lee

Nested Class Summary

Nested classes/interfaces inherited from interface org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

Constructor Summary

ProtobufDecoder(MessageLite prototype)
Creates a new instance.

ProtobufDecoder(MessageLite prototype, ExtensionRegistry extensionRegistry)

Method Summary

protected Object

decode(ChannelHandlerContext ctx, Channel channel, Object msg) Transforms the specified received message into another message and return the transformed message.

Methods inherited from class org.jboss.netty.handler.codec.oneone.OneToOneDecoder

handleUpstream

Methods inherited from class java.lang.Object

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

Constructor Detail

ProtobufDecoder

public ProtobufDecoder(MessageLite prototype)

Creates a new instance.

ProtobufDecoder

public ProtobufDecoder(MessageLite prototype,
                       ExtensionRegistry extensionRegistry)

Method Detail

decode

protected Object decode(ChannelHandlerContext ctx,
                        Channel channel,
                        Object msg)
                 throws Exception

Description copied from class: OneToOneDecoder

Transforms the specified received message into another message and return the transformed message. Return null if the received message is supposed to be discarded.

Specified by:

decode in class OneToOneDecoder

Throws:

Exception