在客户端-服务器游戏中如何处理RPCs ?

I'd like to use PlayN to create a client/server card game, e.g. Hearts. While I'm mostly focusing on the HTML5 output, I'd ideally like to be output-platform-agnostic in case I decide to make an Android client in the future. How should I approach the RPC mechanism?I'd like to use PlayN to create a client/server