* java.util.stream.Stream#filter}. This method is not being deprecated, but we gently encourage
   * you to migrate to streams.
   */
  // TODO(kevinb): how to omit that last sentence when building GWT javadoc?
  public static <E extends @Nullable Object> Set<E> filter(
      Set<E> unfiltered, Predicate<? super E> predicate) {
    if (unfiltered instanceof SortedSet) {
      return filter((SortedSet<E>) unfiltered, predicate);

        "tokenizer" : "fess_japanese_normal",
        "filter" : ["reading_form"]
      },
      "reading_term_analyzer" : {
        "type" : "custom",
        "tokenizer" : "fess_japanese_normal"
      },
      "normalize_analyzer" : {
        "type" : "custom",
        "tokenizer" : "keyword",
        "char_filter" : ["mapping_char"],
        "filter" : ["lowercase"]
      },
      "contents_analyzer" : {

   * underlying multimap.
   *
   * <p>The returned multimap isn't threadsafe or serializable, even if {@code unfiltered} is.
   *
   * <p>Many of the filtered multimap's methods, such as {@code size()}, iterate across every
   * key/value mapping in the underlying multimap and determine which satisfy the filter. When a

      },
      "contents_analyzer_pl" : {
        "type" : "custom",
        "tokenizer" : "standard",
        "char_filter" : ["mapping_char"],
        "filter" : ["lowercase", "content_length_filter", "limit_token_count_filter"]
      },
      "contents_reading_analyzer_pl" : {
        "type" : "custom",
        "tokenizer" : "standard",
        "char_filter" : ["mapping_char"],

        // TODO always returns empty list
        return split(getIndexAdminArrayFields(), ",").get(stream -> stream.filter(StringUtil::isNotBlank)
                .map(String::trim)
                .filter(s -> isNonEmptyValue(source.get(s)))
                .filter(s -> false) // TODO
                .collect(Collectors.toList()));
    }

    String getIndexAdminDateFields();

        "tokenizer" : "fess_japanese_normal",
        "filter" : ["reading_form"]
      },
      "reading_term_analyzer" : {
        "type" : "custom",
        "tokenizer" : "fess_japanese_normal"
      },
      "normalize_analyzer" : {
        "type" : "custom",
        "tokenizer" : "keyword",
        "char_filter" : ["mapping_char"],
        "filter" : ["lowercase"]
      },
      "contents_analyzer" : {

        "tokenizer" : "fess_japanese_normal",
        "filter" : ["reading_form"]
      },
      "reading_term_analyzer" : {
        "type" : "custom",
        "tokenizer" : "fess_japanese_normal"
      },
      "normalize_analyzer" : {
        "type" : "custom",
        "tokenizer" : "keyword",
        "char_filter" : ["mapping_char"],
        "filter" : ["lowercase"]
      },
      "contents_analyzer" : {

            return;
        }
        String filter = subRoleSet.stream().map(s -> String.format(groupFilter, s)).collect(Collectors.joining());
        if (subRoleSet.size() > 1) {
            filter = "(|" + filter + ")";
        }

        if (logger.isDebugEnabled()) {
            logger.debug("Group filter: {}", filter);
        }

                plan.sortedNodes().stream()
                        // 1. Filter steps that are in CREATED state
                        .filter(BuildStep::isCreated)
                        // 2. Check if all predecessors are in a terminal state
                        .filter(step -> step.predecessors.stream().allMatch(BuildStep::isDone))
                        // 3. Process each step

        return false;
    }

    /**
     * Processes a scroll search request.
     * @param request The HTTP request.
     * @param response The HTTP response.
     * @param chain The filter chain.
     */
    protected void processScrollSearchRequest(final HttpServletRequest request, final HttpServletResponse response,
            final FilterChain chain) {
        if (!acceptHttpMethod(request, GET)) {