public function getResultsListPlugin()
    {
        /* @var ResultsPluginService $pluginService */
        $pluginService = $this->getServiceLocator()->get(ResultsPluginService::SERVICE_ID);

        $event = new ResultsListPluginEvent($pluginService->getAllPlugins());
        $this->getServiceLocator()->get(EventManager::SERVICE_ID)->trigger($event);

        // return the list of active plugins
        return array_filter($event->getPlugins(), function ($plugin) {
            return !is_null($plugin) && $plugin->isActive();
        });
    }