public static String filterNormalize()

in src/java/org/apache/nutch/parse/ParseOutputFormat.java [401:467]
60 lines of code
22 McCabe index (conditional complexity)

  public static String filterNormalize(String fromUrl, String toUrl,
      String origin, boolean ignoreInternalLinks, boolean ignoreExternalLinks,
       String ignoreExternalLinksMode, URLFilters filters,
       URLExemptionFilters exemptionFilters, URLNormalizers normalizers,
        String urlNormalizerScope) {
    // ignore links to self (or anchors within the page)
    if (fromUrl.equals(toUrl)) {
      return null;
    }
    if (ignoreExternalLinks || ignoreInternalLinks) {
      URL targetURL = null;
      try {
        targetURL = new URL(toUrl);
      } catch (MalformedURLException e1) {
        return null; // skip it
      }
      if (ignoreExternalLinks) {
        if ("bydomain".equalsIgnoreCase(ignoreExternalLinksMode)) {
          String toDomain = URLUtil.getDomainName(targetURL).toLowerCase();
          //FIXME: toDomain will never be null, correct?
          if (toDomain == null || !toDomain.equals(origin)) {
            return null; // skip it
          }
        } else {
          String toHost = targetURL.getHost().toLowerCase();
          if (!toHost.equals(origin)) { // external host link
            if (exemptionFilters == null // check if it is exempted?
                || !exemptionFilters.isExempted(fromUrl, toUrl)) {
              return null; ///skip it, This external url is not exempted.
            }
          }
        }
      }
      if (ignoreInternalLinks) {
        if ("bydomain".equalsIgnoreCase(ignoreExternalLinksMode)) {
          String toDomain = URLUtil.getDomainName(targetURL).toLowerCase();
          //FIXME: toDomain will never be null, correct?
          if (toDomain == null || toDomain.equals(origin)) {
            return null; // skip it
          }
        } else {
          String toHost = targetURL.getHost().toLowerCase();
          //FIXME: toDomain will never be null, correct?
          if (toHost == null || toHost.equals(origin)) {
            return null; // skip it
          }
        }
      }
    }

    try {
      if (normalizers != null) {
        toUrl = normalizers.normalize(toUrl, urlNormalizerScope); // normalize
                                                                  // the url
      }
      if (filters != null) {
        toUrl = filters.filter(toUrl); // filter the url
      }
      if (toUrl == null) {
        return null;
      }
    } catch (Exception e) {
      return null;
    }

    return toUrl;
  }