* The input object can be either a single string or a list of strings representing URLs.
     *
     * @param obj the object containing anchor URLs (String or List of Strings)
     * @return a set of RequestData objects for the anchor URLs, or null if no valid URLs found
     */
    protected Set<RequestData> getAnchorSet(final Object obj) {
        List<String> anchorList;
        if (obj instanceof final String s) {

    protected static final String ID_TOKEN = "id_token";

    /** OAuth2 authorization code parameter name. */
    protected static final String CODE = "code";

    /** Timeout for token acquisition in milliseconds. */
    protected long acquisitionTimeout = 30 * 1000L;

    /** Cache for storing group information to reduce API calls. */
    protected Cache<String, Pair<String[], String[]>> groupCache;

     *
     * @param input the input object (String[], List, or String)
     * @return joined string with elements separated by spaces, or empty string if invalid input
     */
    public static String join(final Object input) {
        String[] values = null;
        if (input instanceof String[]) {
            values = (String[]) input;
        } else if (input instanceof List) {

      hash *= 31;
      hash += Long.hashCode(array[i]);
    }
    return hash;
  }

  /**
   * Returns a string representation of this array in the same form as {@link
   * Arrays#toString(long[])}, for example {@code "[1, 2, 3]"}.
   */
  @Override
  public String toString() {
    if (isEmpty()) {
      return "[]";
    }

      hash *= 31;
      hash += Integer.hashCode(array[i]);
    }
    return hash;
  }

  /**
   * Returns a string representation of this array in the same form as {@link
   * Arrays#toString(int[])}, for example {@code "[1, 2, 3]"}.
   */
  @Override
  public String toString() {
    if (isEmpty()) {
      return "[]";
    }

     * @return stream of tag-attribute pairs for URL extraction
     */
    @Override
    protected Stream<Pair<String, String>> getChildUrlRules(final ResponseData responseData, final ResultData resultData) {
        final Map<String, String> configMap = getConfigPrameterMap(responseData, ConfigName.CONFIG);
        final String ruleString = configMap.get(Config.HTML_CHILD_URL_RULES);
        if (StringUtil.isBlank(ruleString)) {

        }
        // TODO Long, Integer, String supported only.
        if (StringUtil.isNotBlank(crawlingInfoPager.sessionId)) {
            cb.query().setSessionId_Match(crawlingInfoPager.sessionId);
        }
        cb.query().addOrderBy_CreatedTime_Desc();
    }

    /**
     * Sets up the conditions for storing a crawling information record.

 *
 * <h3>Example</h3>
 *
 * <p>The following code:
 *
 * {@snippet :
 * ListMultimap<String, String> multimap = ArrayListMultimap.create();
 * for (President pres : US_PRESIDENTS_IN_ORDER) {
 *   multimap.put(pres.firstName(), pres.lastName());
 * }
 * for (String firstName : multimap.keySet()) {
 *   List<String> lastNames = multimap.get(firstName);
 *   out.println(firstName + ": " + lastNames);
 * }
 * }
 *

    private static final String LDAP_MANAGER = "ldapManager";

    private static final String ROLE_QUERY_HELPER = "roleQueryHelper";

    private static final String SUGGEST_HELPER = "suggestHelper";

    private static final String SEARCH_ENGINE_CLIENT = "searchEngineClient";

    private static final String DICTIONARY_MANAGER = "dictionaryManager";

///

## Previous Steps Before Starting { #previous-steps-before-starting }

There are many cases where you want to perform some steps **before starting** your application.

For example, you might want to run **database migrations**.

But in most cases, you will want to perform these steps only **once**.