// duplicate host
            try {
                final DuplicateHostHelper duplicateHostHelper = ComponentUtil.getDuplicateHostHelper();
                duplicateHostHelper.init();
            } catch (final Exception e) {
                logger.warn("Could not initialize duplicateHostHelper.", e);
            }

        if (StringUtil.isNotBlank(childUrl)) {
            final DuplicateHostHelper duplicateHostHelper = ComponentUtil.getDuplicateHostHelper();
            final String url = duplicateHostHelper.convert(childUrl);
            super.storeChildUrl(url, parentUrl, weight, depth);
        }
    }

    /**

     */
    protected String replaceDuplicateHost(final String url) {
        try {
            // remove duplicate host
            final DuplicateHostHelper duplicateHostHelper = ComponentUtil.getDuplicateHostHelper();
            return duplicateHostHelper.convert(url);
        } catch (final Exception e) {
            return url;
        }
    }

    /**
     * Extracts anchor URLs from the HTML document.