class ConditionPluginCollection

class ConditionPluginCollection extends DefaultLazyPluginCollection {
  
  /**
   * An array of collected contexts for conditions.
   *
   * @var \Drupal\Component\Plugin\Context\ContextInterface[]
   */
  protected $conditionContexts = [];
  
  /**
   * {@inheritdoc}
   *
   * @return \Drupal\Core\Condition\ConditionInterface
   */
  public function &get($instance_id) {
    return parent::get($instance_id);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getConfiguration() {
    $configuration = parent::getConfiguration();
    // Remove configuration if it matches the defaults.
    foreach ($configuration as $instance_id => $instance_config) {
      $default_config = [];
      $default_config['id'] = $instance_id;
      $default_config += $this->get($instance_id)
        ->defaultConfiguration();
      // In order to determine if a plugin is configured, we must compare it to
      // its default configuration. The default configuration of a plugin does
      // not contain context_mapping and it is not used when the plugin is not
      // configured, so remove the context_mapping from the instance config to
      // compare the remaining values.
      unset($instance_config['context_mapping']);
      ksort($default_config);
      ksort($instance_config);
      if ($default_config === $instance_config) {
        unset($configuration[$instance_id]);
      }
    }
    return $configuration;
  }
  
  /**
   * Sets the condition context for a given name.
   *
   * @param string $name
   *   The name of the context.
   * @param \Drupal\Component\Plugin\Context\ContextInterface $context
   *   The context to add.
   *
   * @return $this
   */
  public function addContext($name, ContextInterface $context) {
    $this->conditionContexts[$name] = $context;
    return $this;
  }
  
  /**
   * Gets the values for all defined contexts.
   *
   * @return \Drupal\Component\Plugin\Context\ContextInterface[]
   *   An array of set contexts, keyed by context name.
   */
  public function getConditionContexts() {
    return $this->conditionContexts;
  }

}