return StringUtil.EMPTY;
        }
        try (final Reader reader = new StringReader(str)) {
            return normalizeText(reader, initialCapacity, maxAlphanumTermSize, maxSymbolTermSize, removeDuplication);
        } catch (final IOException e) {
            return StringUtil.EMPTY;
        }
    }

    public static String normalizeText(final Reader reader, final int initialCapacity, final int maxAlphanumTermSize,

        super();
    }

    @Override
    protected ExtractData createExtractData(final String content) {
        final DOMParser parser = getDomParser();
        try (final Reader reader = new StringReader(content)) {
            parser.parse(new InputSource(reader));
        } catch (final Exception e) {
            logger.warn("Failed to parse the content.", e);
            return new ExtractData(extractString(content));
        }

            final BufferedReader reader = new BufferedReader(new InputStreamReader(new BOMInputStream(stream), charsetName));

            String line;
            final RobotsTxt robotsTxt = new RobotsTxt();
            final List<Directive> currentDirectiveList = new ArrayList<>();
            boolean isGroupRecordStarted = false;
            while ((line = reader.readLine()) != null) {