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()) {
      /*

            final Map<String, String[]> fields = new HashMap<>();
            for (final Map.Entry<String, String[]> entry : request.getParameterMap().entrySet()) {
                final String key = entry.getKey();
                if (key.startsWith("fields.")) {
                    final String[] value = simplifyArray(entry.getValue());
                    fields.put(key.substring("fields.".length()), value);
                }

        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 fields array of fields to search in
     * @param excludes array of words to exclude from results
     * @return list of popular words matching the criteria
     */
    public List<String> getWordList(final SearchRequestType searchRequestType, final String seed, final String[] tags, final String[] roles,
            final String[] fields, final String[] excludes) {

<%@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",

    /**
     * Set a field with the specified date. If the field is not found, it is added. If the field is
     * found, the existing values are replaced.
     */
    operator fun set(
      name: String,
      value: Date,
    ) = set(name, value.toHttpDateString())

    /**
     * Set a field with the specified instant. If the field is not found, it is added. If the field

    /** The key of the configuration. e.g. url */
    String INDEX_FIELD_URL = "index.field.url";

    /** The key of the configuration. e.g. doc_id */
    String INDEX_FIELD_doc_id = "index.field.doc_id";

    /** The key of the configuration. e.g. _id */
    String INDEX_FIELD_ID = "index.field.id";

    /** The key of the configuration. e.g. _version */

            }
            if (FieldUtil.isPublicField(field)) {
                final PropertyDescImpl pd = new PropertyDescImpl(field.getName(), field.getType(), null, null, field, this);
                propertyDescCache.put(fname, pd);
            }
        }
    }

    private void setFieldAccessible(Field field) {
        if (isExceptPrivateAccessible(field)) {
            return;
        }
        try {

     * @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();

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

    /**
     * Checks if the specified field is a search field.
     * @param field The field name to check.
     * @return True if the field is a search field, false otherwise.
     */
    protected boolean isSearchField(final String field) {
        for (final String searchField : getQueryFieldConfig().searchFields) {