gistfile1.java

        public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
            if (e.getMessage() instanceof OFMessage) {
                OFMessage in = (OFMessage)e.getMessage();
                log.debug("Message received: message({}), switch({})", in.getType(), ctx.getChannel().getRemoteAddress());
                switch (in.getType()) {
                    case HELLO:
                        ctx.getChannel().write(factory.getMessage(OFType.FEATURES_REQUEST));
                    case ECHO_REQUEST:
                        int xid = in.getXid();
                        OFMessage out = factory.getMessage(OFType.ECHO_REPLY);
                        out.setXid(xid);
                        //  replies an ECHO_REPLY message
                        ctx.getChannel().write(out);
                        break;
                    case FEATURES_REPLY:
                        log.info("Handshake completed: switch({})", ctx.getChannel().getRemoteAddress());
                        break;
                    case ERROR:
                        OFError error = (OFError)in;
                        log.warn("Error occurred: type({}), switch({})", error.getErrorType(), ctx.getChannel().getRemoteAddress());
                        break;
                    default:
                        controller.invokeMessageListeners(ctx.getChannel(), in);
                }
            }
        }