private void parseListenerProperties()

in helix-core/src/main/java/org/apache/helix/manager/zk/CallbackHandler.java [192:288]
91 lines of code
28 McCabe index (conditional complexity)

  private void parseListenerProperties() {
    BatchMode batchMode = _listener.getClass().getAnnotation(BatchMode.class);
    PreFetch preFetch = _listener.getClass().getAnnotation(PreFetch.class);

    String asyncBatchModeEnabled = System.getProperty(SystemPropertyKeys.ASYNC_BATCH_MODE_ENABLED);
    if (asyncBatchModeEnabled == null) {
      // for backcompatible, the old property name is deprecated.
      asyncBatchModeEnabled =
          System.getProperty(SystemPropertyKeys.LEGACY_ASYNC_BATCH_MODE_ENABLED);
    }

    if (asyncBatchModeEnabled != null) {
      _batchModeEnabled = Boolean.parseBoolean(asyncBatchModeEnabled);
      logger.info("isAsyncBatchModeEnabled by default: {}", _batchModeEnabled);
    }

    if (batchMode != null) {
      _batchModeEnabled = batchMode.enabled();
    }
    if (preFetch != null) {
      _preFetchEnabled = preFetch.enabled();
    }

    Class listenerClass = null;
    switch (_changeType) {
      case IDEAL_STATE:
        listenerClass = IdealStateChangeListener.class;
        break;
      case INSTANCE_CONFIG:
        if (_listener instanceof ConfigChangeListener) {
          listenerClass = ConfigChangeListener.class;
        } else if (_listener instanceof InstanceConfigChangeListener) {
          listenerClass = InstanceConfigChangeListener.class;
        }
        break;
      case CLUSTER_CONFIG:
        listenerClass = ClusterConfigChangeListener.class;
        break;
      case RESOURCE_CONFIG:
        listenerClass = ResourceConfigChangeListener.class;
        break;
      case CUSTOMIZED_STATE_CONFIG:
        listenerClass = CustomizedStateConfigChangeListener.class;
        break;
      case CONFIG:
        listenerClass = ConfigChangeListener.class;
        break;
      case LIVE_INSTANCE:
        listenerClass = LiveInstanceChangeListener.class;
        break;
      case CURRENT_STATE:
        listenerClass = CurrentStateChangeListener.class;
        break;
      case TASK_CURRENT_STATE:
        listenerClass = TaskCurrentStateChangeListener.class;
        break;
      case CUSTOMIZED_STATE_ROOT:
        listenerClass = CustomizedStateRootChangeListener.class;
        break;
      case CUSTOMIZED_STATE:
        listenerClass = CustomizedStateChangeListener.class;
        break;
      case MESSAGE:
      case MESSAGES_CONTROLLER:
        listenerClass = MessageListener.class;
        break;
      case EXTERNAL_VIEW:
      case TARGET_EXTERNAL_VIEW:
        listenerClass = ExternalViewChangeListener.class;
        break;
      case CUSTOMIZED_VIEW:
        listenerClass = CustomizedViewChangeListener.class;
        break;
      case CUSTOMIZED_VIEW_ROOT:
        listenerClass = CustomizedViewRootChangeListener.class;
        break;
      case CONTROLLER:
        listenerClass = ControllerChangeListener.class;
    }

    Method callbackMethod = listenerClass.getMethods()[0];
    try {
      Method method = _listener.getClass().getMethod(callbackMethod.getName(),
          callbackMethod.getParameterTypes());
      BatchMode batchModeInMethod = method.getAnnotation(BatchMode.class);
      PreFetch preFetchInMethod = method.getAnnotation(PreFetch.class);
      if (batchModeInMethod != null) {
        _batchModeEnabled = batchModeInMethod.enabled();
      }
      if (preFetchInMethod != null) {
        _preFetchEnabled = preFetchInMethod.enabled();
      }
    } catch (NoSuchMethodException e) {
      logger.warn("No method {} defined in listener {}", callbackMethod.getName(),
          _listener.getClass().getCanonicalName());
    }
  }