@Override public short ping(RpcRequestMessage.PingNameNodeReq request, RpcResponseMessage.PingNameNodeRes response, RpcNameNodeState errorState) throws Exception { if (!RpcProtocol.verifyProtocol(RpcProtocol.CMD_PING_NAMENODE, request, response)){ return RpcErrors.ERR_PROTOCOL_MISMATCH; } response.setData(request.getOp()+1); return RpcErrors.ERR_OK; }