} catch (final ExecutionException e) {
            throw new CrawlerSystemException(e);
        }
    }

    @Override
    public List<Pattern> getExcludeUrlPatternList(final String sessionId) {
        try {
            return excludeFilterCache.get(sessionId);
        } catch (final ExecutionException e) {
            throw new CrawlerSystemException(e);
        }
    }