Class ProtobufDecoder

java.lang.Object

org.jboss.netty.handler.codec.oneone.OneToOneDecoder

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

All Implemented Interfaces:

ChannelHandler, ChannelUpstreamHandler

@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);
}

Nested Class Summary

Nested classes/interfaces inherited from interface ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private final com.google.protobuf.ExtensionRegistry	extensionRegistry
private static final boolean	HAS_PARSER
private final com.google.protobuf.MessageLite	prototype

Constructor Summary

Constructors

Constructor	Description
ProtobufDecoder(com.google.protobuf.MessageLite prototype)	Creates a new instance.
ProtobufDecoder(com.google.protobuf.MessageLite prototype, com.google.protobuf.ExtensionRegistry extensionRegistry)

Method Summary

Modifier and Type	Method	Description
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 OneToOneDecoder

handleUpstream

Methods inherited from class Object

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

Field Details

HAS_PARSER

private static final boolean HAS_PARSER

prototype

private final com.google.protobuf.MessageLite prototype

extensionRegistry

private final com.google.protobuf.ExtensionRegistry extensionRegistry

Constructor Details

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 Details

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