fessConfig.getIndexFieldClickCount(), //
                    fessConfig.getIndexFieldFavoriteCount(), //
                    fessConfig.getIndexFieldLang());
            // Initialize Set for O(1) lookup performance
            searchFieldSet = new HashSet<>();
            Collections.addAll(searchFieldSet, searchFields);
        }
        if (facetFields == null) {

import jakarta.annotation.PostConstruct;

/**
 * Helper class for managing popular words and suggestions.
 * Provides functionality to retrieve popular words based on search parameters
 * and manages caching for improved performance.
 */
public class PopularWordHelper {
    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(PopularWordHelper.class);

     */
    public Class<? extends RootAction> getActionClass() {
        return actionClass;
    }

    /**
     * Overrides fillInStackTrace to return null for performance optimization.
     * This prevents stack trace generation for this exception type.
     *
     * @return null to skip stack trace generation
     */
    @Override
    public synchronized Throwable fillInStackTrace() {

/**
 * Utility class for handling Base64 encoding and decoding.
 * <p>
 * This class now uses the standard {@link java.util.Base64} implementation
 * instead of a custom implementation, providing better security and performance.
 * The API remains backward compatible with previous versions.
 * </p>
 *
 * @author higa
 */
public abstract class Base64Util {

    /**
     * Do not instantiate.
     */

        this.dataConfigIds = dataConfigIds;
        return this;
    }

    /**
     * Sets the hot thread monitoring interval for performance analysis.
     * Hot threads help identify performance bottlenecks in the crawler process.
     *
     * @param hotThreadInterval monitoring interval in seconds, -1 to disable
     * @return this CrawlJob instance for method chaining
     */

 *
 * <p>Thread-safe operations are supported for registration and retrieval of data stores.
 * The factory caches data store names with a time-based refresh mechanism to improve
 * performance while ensuring up-to-date plugin discovery.</p>
 */
public class DataStoreFactory {
    /** Logger instance for this factory class. */
    private static final Logger logger = LogManager.getLogger(DataStoreFactory.class);

 * <p>
 * This class provides methods to configure the XPath expressions, parser features, and properties.
 * It also includes caching mechanism for XPathAPI instances to improve performance.
 * </p>
 * <p>
 * The extracted text is obtained from the nodes selected by the {@code targetNodePath} XPath expression.

**Alternative Approach**: Instead of relying on GSA API compatibility, we recommend migrating client applications to use Fess's modern JSON API (`/api/v1/documents`), which provides more features and better performance.

---

### Google Site Search (GSS) / Google Custom Search (GSE)

[Fess Site Search](https://github.com/codelibs/fess-site-search) provides a drop-in replacement for GSS/CSE JavaScript.

    /** HTTP status code for OK */
    private static final int HTTP_STATUS_OK = 200;

    /**
     * Cache for client rules mapping client names to their corresponding URL patterns.
     * This cache improves performance by avoiding repeated parsing of client configuration rules.
     * The key is the rule string, and the value is a pair containing the client name and compiled pattern.
     */

            return url;
        }
    }

    /**
     * Gets the character encoding for a parent URL from cache or data service.
     * Caches encoding information to improve performance on subsequent requests.
     *
     * @param parentUrl the parent URL to get encoding for
     * @param sessionId the session ID for the crawling session
     * @return the character encoding, or null if not found