class NettyHttpServerEngine implements ServerEngine {

    @Override
    public void addServant(URL url, NettyHttpHandler handler) {
        checkRegistedContext(url);

        if (serverChannel == null) {
            serverChannel = startServer();
        }
        // need to set the handler name for looking up
        handler.setName(url.getPath());
        String contextName = HttpUriMapper.getContextName(url.getPath());
        // need to check if the NettyContext is there
        NettyHttpContextHandler contextHandler = handlerMap.get(contextName);
        if (contextHandler == null) {
            contextHandler = new NettyHttpContextHandler(contextName);
            handlerMap.put(contextName, contextHandler);
        }
        contextHandler.addNettyHttpHandler(handler);
        registedPaths.add(url.getPath());
    }

    public  NettyHttpServerEngine();
    public  NettyHttpServerEngine(
            String host,
            int port);

}