@Override
    protected void refresh(final List<SelectorData> data) {
        if (CollectionUtils.isEmpty(data)) {
            LOG.info("clear all selector cache, old cache");
            data.forEach(pluginDataSubscriber::unSelectorSubscribe);
            pluginDataSubscriber.refreshSelectorDataAll();
        } else {
            // update cache for UpstreamCacheManager
            pluginDataSubscriber.refreshSelectorDataAll();
            data.forEach(pluginDataSubscriber::onSelectorSubscribe);
        }
    }
@Test
    public void testRefreshCoverage() {
        final SelectorDataRefresh selectorDataRefresh = mockSelectorDataRefresh;
        SelectorData selectorData = new SelectorData();
        List<SelectorData> selectorDataList = new ArrayList<>();
        selectorDataRefresh.refresh(selectorDataList);
        selectorDataList.add(selectorData);
        selectorDataRefresh.refresh(selectorDataList);
    }