return o;
    }

    @Override
    public String toString() {
      return "Functions.identity()";
    }
  }

  /**
   * Returns a function which performs a map lookup. The returned function throws an {@link
   * IllegalArgumentException} if given a key that does not exist in the map. See also {@link
   * #forMap(Map, Object)}, which returns a default value in this case.
   *

                logger.info("No crawling target urls.");
            }
            return;
        }

        doCrawl(sessionId, configList);
    }

    /**
     * Performs the actual crawling operation for the provided data configurations.
     * This method manages the creation and execution of crawler threads,
     * monitors their progress, and handles cleanup operations.
     *

        final String key = entity.getVirtualHost();
        return StringUtil.isBlank(key) ? StringUtil.EMPTY : key;
    }

    /**
     * Retrieves related queries for a given search term.
     * The search is performed using the current virtual host context and
     * the query term is converted to lowercase for case-insensitive matching.
     *
     * @param query the search term to find related queries for

  // 'inputFuture' field is read and where we will have to consider visibility of the write
  // operation in the constructor.
  //
  // 1. In the listener that performs the callback. In this case it is fine since inputFuture is
  //    assigned prior to calling addListener, and addListener happens-before any invocation of the

    @Resource
    protected SearchEngineClient searchEngineClient;

    // ===================================================================================
    // Search Execute
    //

    /**
     * Performs bulk document operations (index multiple documents).
     * Validates document fields and adds default values where necessary.
     *
     * @param body the bulk request body containing documents to process

     * Creates a new instance of the log purging job with default settings.
     */
    public PurgeLogJob() {
        // Default constructor
    }

    /**
     * Executes the log purging job.
     * Performs the following cleanup operations:
     * - Purges old crawling sessions
     * - Purges search logs older than configured days
     * - Purges job logs older than configured days

     */
    public DuplicateHostService() {
        super();
    }

    /**
     * Retrieves a paginated list of duplicate host configurations based on search criteria.
     *
     * <p>This method performs a paginated search through all duplicate host configurations,
     * applying any search filters specified in the pager. The results are sorted
     * by sort order, creation time, regular name, and duplicate hostname.</p>
     *

    protected long requestInterval = 500;

    /**
     * Sends a list of documents to the search engine for indexing.
     * This method handles thumbnail processing, deletes old documents with the same URL,
     * and performs bulk indexing operations with proper error handling.
     *
     * @param searchEngineClient the search engine client to use for indexing
     * @param docList the list of documents to be indexed

            if (authenticator != null) {
                return authenticator.getResponse(responseType);
            }
        }
        return null;
    }

    /**
     * Performs logout operations for the specified user using SSO.
     *
     * @param user The user to logout
     * @return The logout URL from the SSO authenticator, or null if SSO is not available
     */

 * possible sequences of these operations, up to a given number of steps. So, if the caller
 * specifies to use <i>n</i> steps, a total of <i>3^n</i> tests are actually performed.
 *
 * <p>For instance, if <i>steps</i> is 5, one example sequence that will be tested is:
 *
 * <ol>
 *   <li>remove();
 *   <li>hasNext()
 *   <li>hasNext();
 *   <li>remove();
 *   <li>next();
 * </ol>