这部分文档在 `/docs` 下的 Swagger API 文档中显示，并且会告诉外部开发者如何构建*外部 API*。

本例没有实现回调本身（只是一行代码），只有文档部分。

/// tip | 提示

实际的回调只是 HTTP 请求。

实现回调时，要使用 <a href="https://www.encode.io/httpx/" class="external-link" target="_blank">HTTPX</a> 或 <a href="https://requests.readthedocs.io/" class="external-link" target="_blank">Requests</a>。

///

## 编写回调文档代码

应用不执行这部分代码，只是用它来*记录 外部 API* 。

但，您已经知道用 **FastAPI** 创建自动 API 文档有多简单了。

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

  private static final class BelowAll extends Cut<Comparable<?>> {
    private static final BelowAll INSTANCE = new BelowAll();

    private BelowAll() {
      /*
       * No code ever sees this bogus value for `endpoint`: This class overrides both methods that

import jakarta.annotation.PostConstruct;

/**
 * Helper class for managing related content configurations.
 * This class provides functionality to load, cache, and retrieve related content
 * based on search queries and virtual host configurations. It supports both exact
 * term matching and regex pattern matching for flexible content association.
 */
public class RelatedContentHelper extends AbstractConfigHelper {

    /**

import java.net.InetAddress;

/**
 * Utility class for handling IP addresses, particularly IPv6 addresses in URLs.
 * This class provides methods to properly format IPv6 addresses for use in URLs
 * by adding brackets where necessary.
 */
public final class IpAddressUtil {

    /**
     * Private constructor to prevent instantiation of utility class.
     */
    private IpAddressUtil() {

 * #dispatch} is expected to be called concurrently, it is idempotent.
 */
@J2ktIncompatible
@GwtIncompatible
final class ListenerCallQueue<L> {
  // TODO(cpovirk): consider using the logger associated with listener.getClass().
  private static final LazyLogger logger = new LazyLogger(ListenerCallQueue.class);

  // TODO(chrisn): promote AppendOnlyCollection for use here.
  private final List<PerListenerQueue<L>> listeners =

 * <ul>
 *   <li>Retry up to 5 times</li>
 *   <li>Wait 500ms between retries</li>
 * </ul>
 *
 */
public class FaultTolerantClient implements CrawlerClient {

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

    /** The underlying crawler client */
    protected CrawlerClient client;

    /** Maximum number of retry attempts */

import org.codelibs.fess.crawler.exception.ExtractException;
import org.dbflute.utflute.core.PlainTestCase;

/**
 * Enhanced test class for TextExtractor covering improved error messages and edge cases.
 */
public class TextExtractorEnhancedTest extends PlainTestCase {

    private TextExtractor textExtractor;

    @Override
    protected void setUp() throws Exception {
        super.setUp();

/**
 * 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);

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

 *   <li>Clean text conversion from Markdown</li>
 *   <li>Configurable encoding</li>
 * </ul>
 */
public class MarkdownExtractor extends AbstractExtractor {
    /** Logger instance for this class. */
    private static final Logger logger = LogManager.getLogger(MarkdownExtractor.class);

    /** Default encoding for Markdown files. */
    protected String encoding = Constants.UTF_8;

import java.io.Serializable;
import java.util.List;

import org.codelibs.fess.util.ComponentUtil;

/**
 * Pager class for request header management in the Fess search engine.
 * This class provides pagination functionality for displaying and managing
 * request headers in the administration interface.
 */
public class ReqHeaderPager implements Serializable {

    private static final long serialVersionUID = 1L;

    /**