public void crawl(SearchPerformer performer, CrawlableSearchResult sr) {
   if (performer != null && !performer.isStopped()) {
     try {
       SearchTask task = new CrawlTask(this, performer, sr, getOrder(performer.getToken()));
       submitSearchTask(task);
     } catch (Throwable e) {
       LOG.warn("Error scheduling crawling of search result: " + sr);
     }
   } else {
     LOG.warn("Search performer is null or stopped, review your logic");
   }
 }
 public boolean isStopped() {
   return performer.isStopped();
 }