public function validate() { $errors = parent::validate(); if ($this->usesRowPlugin()) { $plugin = $this->displayHandler->getPlugin('row'); if (empty($plugin)) { $errors[] = $this->t('Style @style requires a row style but the row plugin is invalid.', array('@style' => $this->definition['title'])); } else { $result = $plugin->validate(); if (!empty($result) && is_array($result)) { $errors = array_merge($errors, $result); } } } return $errors; }