if (session != null) {
                return session.getId();
            }
            final String preference = r.getParameter("preference");
            if (preference != null) {
                return Integer.toString(preference.hashCode());
            }
            final Object accessType = r.getAttribute(Constants.SEARCH_LOG_ACCESS_TYPE);

    public SearchRequestParams request() {
        return _searchRequestParams;
    }

    public void setPreference(final String preference) {
        _preference = preference;
    }

    public String getPreference() {
        return _preference;
    }

    // ===================================================================================

    public SearchRequestParams request() {
        return _searchRequestParams;
    }

    public void setPreference(final String preference) {
        _preference = preference;
    }

    public String getPreference() {
        return _preference;
    }

    // ===================================================================================

    public SearchRequestParams request() {
        return _searchRequestParams;
    }

    public void setPreference(final String preference) {
        _preference = preference;
    }

    public String getPreference() {
        return _preference;
    }

    // ===================================================================================

     * Defines the sorting order if redirection fails.
     */
    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 static Path getEnvPath(final String envName, final String... names) {
        return getPath("WEB-INF/", "env/" + envName, names);
    }

    /**
     * Gets the path by trying multiple locations in order of preference.
     * First tries to get the real path from servlet context, then checks various
     * fallback locations including source and target directories.
     *
     * @param root the root directory (e.g., "WEB-INF/")

        - name: lang
          in: query
          description: Language
          required: false
          schema:
            type: string
            example: en
        - name: preference
          in: query
          description: String to specify a shard for searching
          required: false
          schema:
            type: string
            example: abc
        - name: callback

  - [Apache Solr](#apache-solr)
  - [Other Search Systems](#other-search-systems)
- [Data Import Methods](#data-import-methods)
- [Configuration Migration](#configuration-migration)
- [API Reference](#api-reference)
- [Troubleshooting](#troubleshooting)
- [Migration Checklist](#migration-checklist)

---

## Supported Migration Sources

Fess provides built-in support and compatibility layers for:

# Sorts for inner hits in collapse queries.
query.collapse.inner.hits.sorts=
# Default languages for queries.
query.default.languages=
# Default preference for JSON queries.
query.json.default.preference=_query
# Default preference for GSA queries.
query.gsa.default.preference=_query
# Language mapping for queries.
query.language.mapping=\
ar=ar\n\
bg=bg\n\
bn=bn\n\
ca=ca\n\
ckb-iq=ckb-iq\n\
ckb_IQ=ckb-iq\n\

    public static final String REQUEST_LANGUAGES = "requestLanguages";

    /** Request page size parameter name. */
    public static final String REQUEST_PAGE_SIZE = "requestPageSize";

    /** Search preference for local node. */
    public static final String SEARCH_PREFERENCE_LOCAL = "_local";

    /** GSA API version identifier. */
    public static final String GSA_API_VERSION = "3.2";