* @param sessionId The session ID.
     */
    @Override
    public void saveSession(final String sessionId) {
        // 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