* @return the compiled Pattern object
         */
        private static Pattern compilePattern(final String pattern) {
            final StringBuilder regex = new StringBuilder();
            regex.append("^"); // Match from the start

            for (int i = 0; i < pattern.length(); i++) {
                final char c = pattern.charAt(i);
                if (c == '*') {

      hostname += "."
    }
    if (!pattern.endsWith(".")) {
      pattern += "."
    }
    // Hostname and pattern are now absolute domain names.

    pattern = pattern.asciiToLowercase()
    // Hostname and pattern are now in lower case -- domain names are case-insensitive.

    if ("*" !in pattern) {
      // Not a wildcard pattern -- hostname and pattern must match exactly.
      return hostname == pattern

        }
        if (client == null) {
            throw new CrawlerSystemException("CrawlerClient instance is null. Cannot register null client.");
        }
        clientMap.put(Pattern.compile(regex), client);
    }

    /**
     * Adds a client with a regular expression pattern at a specific position.
     * @param regex The regular expression to match URLs.
     * @param client The CrawlerClient instance.

    }

    /**
     * Adds an include URL pattern for the specified session.
     * @param sessionId the session ID
     * @param url the URL pattern to include
     */
    public synchronized void addIncludeUrlPattern(final String sessionId, final String url) {
        final List<Pattern> patternList = getIncludeUrlPatternList(sessionId);
        patternList.add(Pattern.compile(url));
    }

    /**

    }

    /**
     * Converts a pattern string to a plain pattern string without delimiters.
     *
     * @param pattern the pattern string
     * @return the plain pattern string without delimiters
     */
    protected static String toPlainPattern(final String pattern) {
        final StringBuilder buf = new StringBuilder(pattern.length());
        for (int i = 0; i < pattern.length(); ++i) {

     * @param regex the regular expression pattern
     */
    public void addRule(final String key, final String regex) {
        regexMap.put(key, Pattern.compile(regex));
    }

    /**
     * Adds a compiled regular expression rule for the specified field.
     * @param key the field name to match against
     * @param pattern the compiled regular expression pattern
     */

    }

    /**
     * Gets the list of include URL patterns for the specified session.
     *
     * @param sessionId The session ID.
     * @return The list of compiled include patterns.
     * @throws CrawlerSystemException if the patterns cannot be loaded.
     */
    @Override
    public List<Pattern> getIncludeUrlPatternList(final String sessionId) {
        try {

          "pattern": "/^((?!question).)*$/is"
        },
        {
          "type": "descriptionMatches",
          "pattern": "/^((?!Describe the feature).)*$/is"
        },
        {
          "type": "titleMatches",
          "pattern": "/^((?!critical|urgent).)*$/s"
        },
        {
          "type": "descriptionMatches",
          "pattern": "/^((?!critical|urgent).)*$/s"
        }
      ]

        final List<Pattern> includeList = getUrlFilterService().getIncludeUrlPatternList(sessionId);
        final List<Pattern> excludeList = getUrlFilterService().getExcludeUrlPatternList(sessionId);

        if (!includeList.isEmpty()) {
            boolean match = false;
            for (final Pattern pattern : includeList) {
                final Matcher matcher = pattern.matcher(url);

            logger.debug("pattern1: {}, pattern2: {}", pattern1Str, pattern2Str);
        }
        if (pattern1Str != null) {
            pattern1 = Pattern.compile(pattern1Str);
            pattern2 = Pattern.compile(pattern2Str);
        }
    }

    @Override
    public TokenStream create(final TokenStream tokenStream) {
        return new PatternConcatenationFilter(tokenStream, pattern1, pattern2);
    }