new ImmutableListMultimap.Builder<Integer, String>()
            .put(4, "Inky")
            .put(6, "Blinky")
            .put(5, "Pinky")
            .put(5, "Pinky")
            .put(5, "Clyde")
            .build();

    List<String> badGuys = Arrays.asList("Inky", "Blinky", "Pinky", "Pinky", "Clyde");
    Function<String, Integer> stringLengthFunction =
        new Function<String, Integer>() {

   * List<String> badGuys =
   *     Arrays.asList("Inky", "Blinky", "Pinky", "Pinky", "Clyde");
   * Function<String, Integer> stringLengthFunction = ...;
   * Multimap<Integer, String> index =
   *     Multimaps.index(badGuys, stringLengthFunction);
   * System.out.println(index);
   * }
   *
   * <p>prints
   *
   * {@snippet :
   * {4=[Inky], 6=[Blinky], 5=[Pinky, Pinky, Clyde]}
   * }
   *

When adding links which point to resources within git repositories, like
KEPs or supporting documentation, please reference a specific commit and avoid
linking directly to the master branch. This ensures that links reference a
specific point in time, rather than a document that may change over time.

    public void setDomain(final String domain) {
        this.domain = domain;
    }

    @Override
    public String getLink() {
        return this.link;
    }

    @Override
    public void setLink(final String link) {
        this.link = link;
    }

    /**
     * @return the key
     */
    @Override
    public String getKey() {
        return this.key;
    }

    /**

            public void visit(final Link link) {
                final String destination = link.getDestination();
                if (StringUtil.isNotBlank(destination)) {
                    links.add(destination);
                }
                super.visit(link);
            }
        });

        if (!links.isEmpty()) {
            extractData.putValues("links", links.toArray(new String[0]));
        }
    }

        final SitemapAlternateLink link1 = sitemapUrl.getAlternateLinks().get(0);
        assertEquals("en", link1.getHreflang());
        assertEquals("http://www.example.com/en/page.html", link1.getHref());

        final SitemapAlternateLink link2 = sitemapUrl.getAlternateLinks().get(1);
        assertEquals("ja", link2.getHreflang());

    this.lastEntry = ENDPOINT;
    if (links != null) {
      Arrays.fill(links, 0, size(), 0);
    }
    super.clear();
  }

  /*
   * For discussion of the safety of the following methods, see the comments near the end of
   * CompactHashMap.
   */

  private long[] requireLinks() {
    return requireNonNull(links);
  }

  private long link(int i) {
    return requireLinks()[i];
  }

            }
            roots.remove(root);
            links = null;
        }

        if (links == null) {
            log.trace("Loadings roots");
            final String refServerName = domain;
            dr = fetchRootReferral(tf, domain, root, refServerName);
            links = cacheRootReferral(tf, domain, root, roots, dr, links);
        } else if (links instanceof NegativeCacheEntry) {

                 */
                CacheEntry links = (CacheEntry) roots.get(root);
                if (links != null && now > links.expiration) {
                    roots.remove(root);
                    links = null;
                }

                if (links == null) {
                    trans = getDc(domain, auth);
                    if (trans == null) {
                        return null;

        CloseableUtil.closeQuietly(in);

        // Verify link metadata
        final String[] links = extractData.getValues("links");
        assertNotNull(links);
        assertTrue(links.length > 0);

        boolean foundGitHubLink = false;
        for (final String link : links) {
            if (link.contains("github.com/codelibs/fess-crawler")) {
                foundGitHubLink = true;