RelationshipManager.php

<?php

namespace Drupal\ctools\Plugin;

use Drupal\Core\Plugin\Context\ContextAwarePluginManagerTrait;
use Drupal\Core\Plugin\DefaultPluginManager;
use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Extension\ModuleHandlerInterface;

/**
 * Provides the Relationship plugin manager.
 */
class RelationshipManager extends DefaultPluginManager implements RelationshipManagerInterface {
    use ContextAwarePluginManagerTrait;
    
    /**
     * Constructor for RelationshipManager objects.
     *
     * @param \Traversable $namespaces
     *   An object that implements \Traversable which contains the root paths
     *   keyed by the corresponding namespace to look for plugin implementations.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   Cache backend instance to use.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler to invoke the alter hook with.
     */
    public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
        parent::__construct('Plugin/Relationship', $namespaces, $module_handler, 'Drupal\\ctools\\Plugin\\RelationshipInterface', 'Drupal\\ctools\\Annotation\\Relationship');
        $this->alterInfo('ctools_relationship_info');
        $this->setCacheBackend($cache_backend, 'ctools_relationship_plugins');
    }

}