class SofaRegistrySubscribeCallback implements SubscriberDataObserver, ConfigDataObserver {

    @Override
    public void handleData(String dataId, UserData userData) {

        if (dataId == null) {
            return;
        }

        this.lastUserData = userData;

        printUserData(dataId, userData);
        if (flag != null) {
            flag[0].compareAndSet(false, true);
        }

        if (canNotify()) {
            flag = null; // 已经没作用了
            composeAndNotify(userData, lastConfigData);
        }
    }

    public  SofaRegistrySubscribeCallback();

}