interface MigrationPluginManagerInterface

interface MigrationPluginManagerInterface extends PluginManagerInterface {
    
    /**
     * Create pre-configured instance of plugin derivatives.
     *
     * @param array $id
     *   Either the plugin ID or the base plugin ID of the plugins being
     *   instantiated. Also accepts an array of plugin IDs and an empty array to
     *   load all plugins.
     * @param array $configuration
     *   An array of configuration relevant to the plugin instances. Keyed by the
     *   plugin ID.
     *
     * @return \Drupal\migrate\Plugin\MigrationInterface[]
     *   Fully configured plugin instances.
     *
     * @throws \Drupal\Component\Plugin\Exception\PluginException
     *   If an instance cannot be created, such as if the ID is invalid.
     */
    public function createInstances($id, array $configuration = []);
    
    /**
     * Creates a stub migration plugin from a definition array.
     *
     * @param array $definition
     *   The migration definition. If an 'id' key is set then this will be used as
     *   the migration ID, if not a random ID will be assigned.
     *
     * @return \Drupal\migrate\Plugin\Migration
     *   The stub migration.
     */
    public function createStubMigration(array $definition);
    
    /**
     * Create migrations given a tag.
     *
     * @param string $tag
     *   A migration tag we want to filter by.
     *
     * @return array|\Drupal\migrate\Plugin\MigrationInterface[]
     *   An array of migration objects with the given tag, or an empty array if no
     *   migrations with that tag exist.
     */
    public function createInstancesByTag($tag);

}