for (Field field : httpHeadersFields()) {
      httpHeaders.add((String) field.get(null));
    }
    assertThat(httpHeaders.build()).containsNoDuplicates();
  }

  private static ImmutableSet<Field> httpHeadersFields() {
    ImmutableSet.Builder<Field> builder = ImmutableSet.builder();
    for (Field field : HttpHeaders.class.getDeclaredFields()) {
      /*

        fields.put(key, value);
    }

    public String getLogMessage() {
        return getSearchWord();
    }

    @Override
    public Map<String, Object> toSource() {
        final Map<String, Object> sourceMap = super.toSource();
        if (fields != null) {
            sourceMap.putAll(fields);
        }

     * @param key the field name to match against
     * @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

        }
        return SortBuilders.fieldSort(field).order(order);
    }

    /**
     * Checks if the specified field is a search field.
     * Uses O(1) Set lookup for improved performance.
     * @param field The field name to check.
     * @return True if the field is a search field, false otherwise.
     */
    protected boolean isSearchField(final String field) {

                try {
                    suggester.settings().array().add(SuggestSettings.DefaultKeys.SUPPORTED_FIELDS, field);
                } catch (final SuggestSettingsException e) {
                    logger.warn("Failed to add suggest field: field={}", field, e);
                }
            }));

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<h2>Query Syntax</h2>
<dl>
	<dt>Field</dt>
	<dd>
		You can search any field by typing the field name followed by a colon
		":" and then the term you are looking for. If you want to find
		documents which has "Fess" as the document title, you can enter:
		<pre>title:Fess</pre>
		The available fields are "url", "host", "site", "title", "content",

    extends AggregateFuture<V, C> {
  /*
   * We access this field racily but safely. For discussion of a similar situation, see the comments
   * on the fields of TimeoutFuture. This field is slightly different from the fields discussed
   * there: cancel() never reads this field, only writes to it. That makes the race here completely
   * harmless, rather than just 99.99% harmless.
   */

     * @param id the document ID to retrieve
     * @param fields the fields to include in the response (null for all fields)
     * @return the document as a map of field names to values, or null if not found
     */
    public Map<String, Object> getDocument(final SearchEngineClient searchEngineClient, final String id, final String[] fields) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

     * Specifies the language preference if redirection fails.
     */
    public String lang;

    /**
     * Additional fields map for error page fallback.
     * Contains extra search parameters as key-value pairs if redirection fails.
     */
    public Map<String, String[]> fields = new HashMap<>();

    /** Mapping type for array fields. */
    public static final String MAPPING_TYPE_ARRAY = "array";

    /** Mapping type for string fields. */
    public static final String MAPPING_TYPE_STRING = "string";

    /** Mapping type for long fields. */
    public static final String MAPPING_TYPE_LONG = "long";

    /** Mapping type for double fields. */