Package io.netty.handler.codec.protobuf

Class ProtobufDecoder

  • All Implemented Interfaces:
    io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler
    @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 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

        io.netty.channel.ChannelHandler.Sharable

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

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected void decode​(io.netty.channel.ChannelHandlerContext ctx, io.netty.buffer.ByteBuf msg, List<Object> out)
      Decode from one message to an other.

      • Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

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

      • Methods inherited from class io.netty.channel.ChannelHandlerAdapter

        ensureNotSharable, handlerAdded, handlerRemoved, isSharable

      • 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​(io.netty.channel.ChannelHandlerContext ctx,
                      io.netty.buffer.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<io.netty.buffer.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