class SelectionPluginManager

class SelectionPluginManager extends DefaultPluginManager implements SelectionPluginManagerInterface, FallbackPluginManagerInterface {
    
    /**
     * {@inheritdoc}
     */
    public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
        $this->alterInfo('entity_reference_selection');
        $this->setCacheBackend($cache_backend, 'entity_reference_selection_plugins');
        parent::__construct('Plugin/EntityReferenceSelection', $namespaces, $module_handler, 'Drupal\\Core\\Entity\\EntityReferenceSelection\\SelectionInterface', 'Drupal\\Core\\Entity\\Annotation\\EntityReferenceSelection');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getInstance(array $options) {
        if (!isset($options['target_type'])) {
            throw new \InvalidArgumentException("Missing required 'target_type' property for a EntityReferenceSelection plugin.");
        }
        // Initialize default options.
        $options += [
            'handler' => $this->getPluginId($options['target_type'], 'default'),
        ];
        // A specific selection plugin ID was already specified.
        if (strpos($options['handler'], ':') !== FALSE) {
            $plugin_id = $options['handler'];
        }
        else {
            $plugin_id = $this->getPluginId($options['target_type'], $options['handler']);
        }
        unset($options['handler']);
        return $this->createInstance($plugin_id, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getPluginId($target_type, $base_plugin_id) {
        // Get all available selection plugins for this entity type.
        $selection_handler_groups = $this->getSelectionGroups($target_type);
        // Sort the selection plugins by weight and select the best match.
        uasort($selection_handler_groups[$base_plugin_id], [
            'Drupal\\Component\\Utility\\SortArray',
            'sortByWeightElement',
        ]);
        end($selection_handler_groups[$base_plugin_id]);
        $plugin_id = key($selection_handler_groups[$base_plugin_id]);
        return $plugin_id;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSelectionGroups($entity_type_id) {
        $plugins = [];
        $definitions = $this->getDefinitions();
        // Do not display the 'broken' plugin in the UI.
        unset($definitions['broken']);
        foreach ($definitions as $plugin_id => $plugin) {
            if (empty($plugin['entity_types']) || in_array($entity_type_id, $plugin['entity_types'])) {
                $plugins[$plugin['group']][$plugin_id] = $plugin;
            }
        }
        return $plugins;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSelectionHandler(FieldDefinitionInterface $field_definition, EntityInterface $entity = NULL) {
        $options = $field_definition->getSetting('handler_settings') ?: [];
        $options += [
            'target_type' => $field_definition->getFieldStorageDefinition()
                ->getSetting('target_type'),
            'handler' => $field_definition->getSetting('handler'),
            'entity' => $entity,
        ];
        return $this->getInstance($options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFallbackPluginId($plugin_id, array $configuration = []) {
        return 'broken';
    }

}