* alternative or supplementary search terms to improve search results.
 */
public class RelatedQueryHelper extends AbstractConfigHelper {
    private static final Logger logger = LogManager.getLogger(RelatedQueryHelper.class);

    /**
     * Map storing related queries organized by virtual host key and search term.

 * and converting XContent objects to different output formats.
 */
public final class SearchEngineUtil {

    private static final Logger logger = LogManager.getLogger(SearchEngineUtil.class);

    /**
     * Private constructor to prevent instantiation of this utility class.
     */
    private SearchEngineUtil() {
    }

    /**

/**
 * API action for admin related query management.
 * Provides REST endpoints for managing related search queries.
 */
public class ApiAdminRelatedqueryAction extends FessApiAdminAction {

    private static final Logger logger = LogManager.getLogger(ApiAdminRelatedqueryAction.class);

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

 * This searcher handles query execution, response processing, and document highlighting.
 */
public class DefaultSearcher extends RankFusionSearcher {

    /** Logger for this class. */
    private static final Logger logger = LogManager.getLogger(DefaultSearcher.class);

    /**
     * Creates a new instance of DefaultSearcher.
     * This constructor initializes the default rank fusion searcher for performing

 */
public class SuggestHelper {
    /**
     * Constructs a new suggest helper.
     */
    public SuggestHelper() {
        // do nothing
    }

    private static final Logger logger = LogManager.getLogger(SuggestHelper.class);

    /** The separator for text content. */
    protected static final String TEXT_SEP = " ";

    /** The suggester instance for handling suggest operations. */

 */
public class PingSearchEngineJob {

    /**
     * Default constructor.
     */
    public PingSearchEngineJob() {
        // Default constructor
    }

    private static final Logger logger = LogManager.getLogger(PingSearchEngineJob.class);

    /**
     * Executes the ping job.
     *
     * @return the execution result
     */
    public String execute() {

        if (session == null) {
            if (logger.isDebugEnabled()) {
                logger.debug("Session not found. sessionId={}", sessionId);
            }
            return null;
        }
        if (isExpired(session)) {
            sessionCache.remove(sessionId);
            if (logger.isDebugEnabled()) {

 * based on crawling configuration parameters.
 */
public class FessUrlQueueService extends OpenSearchUrlQueueService {

    private static final Logger logger = LogManager.getLogger(FessUrlQueueService.class);

    /** Configuration value for sequential URL processing order */
    protected static final String ORDER_SEQUENTIAL = "sequential";

            if (logger.isDebugEnabled()) {
                logger.debug("SuggestCreator is stopped.", e);
            } else if (logger.isInfoEnabled()) {
                logger.info("SuggestCreator is stopped.");
            }
            exitCode = Constants.EXIT_FAIL;
        } catch (final Throwable t) {
            logger.error("SuggestCreator terminated unexpectedly.", t);

        final String sessionId = request.getParameter("sessionId");

        if (logger.isDebugEnabled()) {
            logger.debug("Processing stream request. sessionId={}, messageLength={}", sessionId, message != null ? message.length() : 0);
        }

        if (StringUtil.isBlank(message)) {
            if (logger.isDebugEnabled()) {
                logger.debug("Message is required but was empty for stream request");
            }