code: @SuppressWarnings("unchecked")
      private static synchronized Map<String, Boolean> getCache(GraphRewrite event)
      {
          Map<String, Boolean> result = (Map<String, Boolean>)event.getRewriteContext().get(ClassificationServiceCache.class);
          if (result == null)
          {
              result = Collections.synchronizedMap(new LRUMap(30000));
              event.getRewriteContext().put(ClassificationServiceCache.class, result);
          }
          return result;
      }
docs: Keep a cache of items files associated with classification in order to improve performance.