//                                                                           =========
    private static final ThumbnailQueueDbm _instance = new ThumbnailQueueDbm();

    private ThumbnailQueueDbm() {
    }

    public static ThumbnailQueueDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final FavoriteLogDbm _instance = new FavoriteLogDbm();

    private FavoriteLogDbm() {
    }

    public static FavoriteLogDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final ElevateWordDbm _instance = new ElevateWordDbm();

    private ElevateWordDbm() {
    }

    public static ElevateWordDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final ClickLogDbm _instance = new ClickLogDbm();

    private ClickLogDbm() {
    }

    public static ClickLogDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final JobLogDbm _instance = new JobLogDbm();

    private JobLogDbm() {
    }

    public static JobLogDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final KeyMatchDbm _instance = new KeyMatchDbm();

    private KeyMatchDbm() {
    }

    public static KeyMatchDbm getInstance() {
        return _instance;
    }

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

   */
  fun <T : CallEvent> removeUpToEvent(eventClass: Class<T>): T {
    val fullEventSequence = eventSequence.toList()
    try {
      while (true) {
        val event = takeEvent()
        if (eventClass.isInstance(event)) {
          return eventClass.cast(event)
        }
      }
    } catch (e: NoSuchElementException) {
      throw AssertionError("full event sequence: $fullEventSequence", e)
    }
  }

    //                                                                           =========
    private static final BadWordDbm _instance = new BadWordDbm();

    private BadWordDbm() {
    }

    public static BadWordDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final BoostDocumentRuleDbm _instance = new BoostDocumentRuleDbm();

    private BoostDocumentRuleDbm() {
    }

    public static BoostDocumentRuleDbm getInstance() {
        return _instance;
    }

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

    //                                                                           =========
    private static final FileAuthenticationDbm _instance = new FileAuthenticationDbm();

    private FileAuthenticationDbm() {
    }

    public static FileAuthenticationDbm getInstance() {
        return _instance;
    }

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