final CrawlerContext crawlerContext = CrawlingParameterUtil.getCrawlerContext();
        final UrlQueueService<UrlQueue<?>> urlQueueService = CrawlingParameterUtil.getUrlQueueService();
        if (!urlQueueService.visited(urlQueue)) {
            if (checkAccessCount(crawlerContext)) {
                final AccessResult<?> accessResult = createAccessResult(responseData, resultData);
                if (logger.isDebugEnabled()) {

        // TODO use cache
    }

    /**
     * Checks if a URL has been visited by looking in both the queue and access results.
     *
     * @param urlQueue The URL queue entry to check.
     * @return true if the URL has been visited, false otherwise.
     */
    @Override
    public boolean visited(final OpenSearchUrlQueue urlQueue) {
        final String url = urlQueue.getUrl();

 * class CrawlingService extends AbstractScheduledService {
 *   private Set<Uri> visited;
 *   private Queue<Uri> toCrawl;
 *   protected void startUp() throws Exception {
 *     toCrawl = readStartingUris();
 *   }
 *
 *   protected void runOneIteration() throws Exception {
 *     Uri uri = toCrawl.remove();
 *     Collection<Uri> newUris = crawl(uri);
 *     visited.add(uri);
 *     for (Uri newUri : newUris) {

 * class CrawlingService extends AbstractScheduledService {
 *   private Set<Uri> visited;
 *   private Queue<Uri> toCrawl;
 *   protected void startUp() throws Exception {
 *     toCrawl = readStartingUris();
 *   }
 *
 *   protected void runOneIteration() throws Exception {
 *     Uri uri = toCrawl.remove();
 *     Collection<Uri> newUris = crawl(uri);
 *     visited.add(uri);
 *     for (Uri newUri : newUris) {

      return true;
    }
    return hasCycle(network.asGraph());
  }

  /**
   * Performs a traversal of the nodes reachable from {@code startNode}. If we ever reach a node
   * we've already visited (following only outgoing edges and without reusing edges), we know
   * there's a cycle in the graph.
   */
  private static <N> boolean subgraphHasCycle(

      return true;
    }
    return hasCycle(network.asGraph());
  }

  /**
   * Performs a traversal of the nodes reachable from {@code startNode}. If we ever reach a node
   * we've already visited (following only outgoing edges and without reusing edges), we know
   * there's a cycle in the graph.
   */
  private static <N> boolean subgraphHasCycle(

        private int indexToRemove = ABSENT;
        private int expectedModCount = biMap.modCount;

        // Calls to setValue on inverse entries can move already-visited entries to the end.
        // Make sure we don't visit those.
        private int remaining = biMap.size;

        private void checkForComodification() {
          if (biMap.modCount != expectedModCount) {

            return null;
        }

        @Override
        public void saveSession(String sessionId) {
            // Do nothing in test
        }

        @Override
        public boolean visited(OpenSearchUrlQueue urlQueue) {
            return false;
        }

        @Override
        public void generateUrlQueues(String sessionId, String url) {
            // Do nothing in test
        }

        }

        @Override
        public int hashCode() {
            return getClass().hashCode();
        }

        @Override
        public void visit(org.apache.lucene.search.QueryVisitor visitor) {
            // Empty implementation for test
        }
    }

    public void test_execute_withUnknownQueryType() {
        // Test executing BoostQuery with an unknown query type inside

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