protected Set<String> facetFieldSet;

    /** Array of fields that can be used for sorting search results */
    protected String[] sortFields;

    /** Set of fields that can be used for sorting for O(1) lookup */
    protected Set<String> sortFieldSet;

    /** Set of fields that are allowed in API responses */
    protected Set<String> apiResponseFieldSet;

    /** Set of fields that are not analyzed during indexing */

                    return;
                }
            } else { /* Basic */
                final String auth = new String(Base64.decode(msg.substring(6)), "US-ASCII");
                int index = auth.indexOf(':');
                String user = index != -1 ? auth.substring(0, index) : auth;
                final String password = index != -1 ? auth.substring(index + 1) : "";
                index = user.indexOf('\\');

                    return;
                }
            } else { /* Basic */
                final String auth = new String(Base64.decode(msg.substring(6)), "US-ASCII");
                int index = auth.indexOf(':');
                String user = index != -1 ? auth.substring(0, index) : auth;
                final String password = index != -1 ? auth.substring(index + 1) : "";
                index = user.indexOf('\\');

    /** Constant used to indicate that query-based preference should be used for search routing */
    protected static final String PREFERENCE_QUERY = "_query";

    /** Prefix used to identify sort parameters in search queries */
    protected String sortPrefix = "sort:";

    /** Additional query string to be appended to all search queries */
    protected String additionalQuery;

     */
    public String sort;

    /**
     * Language parameter for error page fallback.
     * 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<>();

     */
    public String[] getInputs() {
        return inputs == null ? null : inputs.clone();
    }

    /**
     * Returns all input sequences joined with newline characters as a single string.
     * This is useful for display purposes in forms and user interfaces.
     *
     * @return string representation of all inputs separated by newlines, or empty string if inputs is null
     */

     *
     * @param userAgent the user agent string to match against directives,
     *                 can be null (treated as empty string)
     * @return the most specific matching directive, or null if no directive matches
     */
    public Directive getMatchedDirective(final String userAgent) {
        final String target;
        if (userAgent == null) {
            target = StringUtil.EMPTY;

     *
     * @param <K> the key type of {@link ConcurrentSkipListMap}
     * @param <V> the value type of {@link ConcurrentSkipListMap}
     * @param c the comparator for sorting the map
     * @return a new instance of {@link ConcurrentSkipListMap}
     * @see ConcurrentSkipListMap#ConcurrentSkipListMap(Comparator)
     */

#### JSON Search API

**Endpoints**:
- `GET /api/v1/documents?q={query}` (recommended)
- `GET /json/?q={query}` (legacy, for backward compatibility)

**Parameters**:
- `q` - Query string
- `num` - Results per page (default: 20)
- `start` - Starting offset (default: 0)
- `fields.label` - Label filter
- `lang` - Language preference

**Example**:
```bash
# Using the recommended endpoint

     */
    @Size(max = 10)
    public String popularWord;

    /**
     * Character encoding to use for CSV file exports.
     * This setting affects the encoding of downloaded CSV files.
     */
    @Required
    @Size(max = 20)
    public String csvFileEncoding;

    /**
     * Number of days to keep search logs before purging.