class Taxonomy

class Taxonomy extends NumericArgument implements ContainerFactoryPluginInterface {
  
  /**
   * @var \Drupal\Core\Entity\EntityStorageInterface
   */
  protected $termStorage;
  
  /**
   * {@inheritdoc}
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityStorageInterface $term_storage) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->termStorage = $term_storage;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($configuration, $plugin_id, $plugin_definition, $container->get('entity_type.manager')
      ->getStorage('taxonomy_term'));
  }
  
  /**
   * Override the behavior of title(). Get the title of the node.
   */
  public function title() {
    // There might be no valid argument.
    if ($this->argument) {
      $term = $this->termStorage
        ->load($this->argument);
      if (!empty($term)) {
        return $term->getName();
      }
    }
    // TODO review text
    return $this->t('No name');
  }

}