@@ -0,0 +1,1245 @@
+package alluxio.worker.netty;%0A%0Aimport alluxio.network.protocol.RPCErrorResponse;%0Aimport alluxio.network.protocol.RPCMessage;%0Aimport alluxio.network.protocol.RPCProtoMessage;%0Aimport alluxio.network.protocol.RPCResponse;%0Aimport alluxio.proto.dataserver.Protocol;%0Aimport io.netty.channel.ChannelHandlerContext;%0Aimport io.netty.channel.ChannelInboundHandlerAdapter;%0A%0A/**%0A * Netty handler which replies to the client with an unknown message error for message types%0A * which are no longer supported.%0A */%0Apublic class DataServerUnsupportedMessageHandler extends ChannelInboundHandlerAdapter %7B%0A  @Override%0A  public void channelRead(ChannelHandlerContext ctx, Object object) throws Exception %7B%0A    if (object instanceof RPCProtoMessage) %7B // Unknown proto message, reply proto.%0A      RPCProtoMessage resp =%0A          RPCProtoMessage.createResponse(Protocol.Status.Code.UNIMPLEMENTED, %22%22, null, null);%0A      ctx.writeAndFlush(resp);%0A    %7D else if (object instanceof RPCMessage)%7B // Unknown non-proto message, reply non-proto.%0A      RPCErrorResponse resp = new RPCErrorResponse(RPCResponse.Status.UNKNOWN_MESSAGE_ERROR);%0A      ctx.writeAndFlush(resp);%0A    %7D else %7B // Unknown message, this should not happen.%0A      ctx.fireChannelRead(object);%0A    %7D%0A  %7D%0A%7D%0A

Add unsupported message handler.