class FieldMigration

class FieldMigration extends Migration implements ContainerFactoryPluginInterface {
    
    /**
     * Flag indicating whether the field data has been filled already.
     *
     * @var bool
     */
    protected $init = FALSE;
    
    /**
     * The migration field discovery service.
     *
     * @var \Drupal\migrate_drupal\FieldDiscoveryInterface
     */
    protected $fieldDiscovery;
    
    /**
     * Constructs a FieldMigration.
     *
     * @param array $configuration
     *   Plugin configuration.
     * @param string $plugin_id
     *   The plugin ID.
     * @param mixed $plugin_definition
     *   The plugin definition.
     * @param \Drupal\migrate\Plugin\MigrationPluginManagerInterface $migration_plugin_manager
     *   The migration plugin manager.
     * @param \Drupal\migrate\Plugin\MigratePluginManager $source_plugin_manager
     *   The source migration plugin manager.
     * @param \Drupal\migrate\Plugin\MigratePluginManager $process_plugin_manager
     *   The process migration plugin manager.
     * @param \Drupal\migrate\Plugin\MigrateDestinationPluginManager $destination_plugin_manager
     *   The destination migration plugin manager.
     * @param \Drupal\migrate\Plugin\MigratePluginManager $id_map_plugin_manager
     *   The ID map migration plugin manager.
     * @param \Drupal\migrate_drupal\FieldDiscoveryInterface $field_discovery
     *   The migration field discovery service.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationPluginManagerInterface $migration_plugin_manager, MigratePluginManager $source_plugin_manager, MigratePluginManager $process_plugin_manager, MigrateDestinationPluginManager $destination_plugin_manager, MigratePluginManager $id_map_plugin_manager, FieldDiscoveryInterface $field_discovery) {
        parent::__construct($configuration, $plugin_id, $plugin_definition, $migration_plugin_manager, $source_plugin_manager, $process_plugin_manager, $destination_plugin_manager, $id_map_plugin_manager);
        $this->fieldDiscovery = $field_discovery;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('plugin.manager.migration'), $container->get('plugin.manager.migrate.source'), $container->get('plugin.manager.migrate.process'), $container->get('plugin.manager.migrate.destination'), $container->get('plugin.manager.migrate.id_map'), $container->get('migrate_drupal.field_discovery'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getProcess() {
        if (!$this->init) {
            $this->init = TRUE;
            $this->fieldDiscovery
                ->addAllFieldProcesses($this);
        }
        return parent::getProcess();
    }

}