class DestinationBase

abstract class DestinationBase extends PluginBase implements MigrateDestinationInterface, RequirementsInterface {
  
  /**
   * Indicates whether the destination can be rolled back.
   *
   * @var bool
   */
  protected $supportsRollback = FALSE;
  
  /**
   * The rollback action to be saved for the last imported item.
   *
   * @var int
   */
  protected $rollbackAction = MigrateIdMapInterface::ROLLBACK_DELETE;
  
  /**
   * The migration.
   *
   * @var \Drupal\migrate\Plugin\MigrationInterface
   */
  protected $migration;
  
  /**
   * Constructs an entity destination plugin.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin ID for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
   *   The migration.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->migration = $migration;
  }
  
  /**
   * {@inheritdoc}
   */
  public function rollbackAction() {
    return $this->rollbackAction;
  }
  
  /**
   * {@inheritdoc}
   */
  public function checkRequirements() {
    if (empty($this->pluginDefinition['requirements_met'])) {
      throw new RequirementsException(sprintf("Destination plugin '%s' did not meet the requirements", $this->pluginId));
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function rollback(array $destination_identifier) {
    // By default we do nothing.
  }
  
  /**
   * {@inheritdoc}
   */
  public function supportsRollback() {
    return $this->supportsRollback;
  }
  
  /**
   * For a destination item being updated, set the appropriate rollback action.
   *
   * @param array $id_map
   *   The map row data for the item.
   * @param int $update_action
   *   The rollback action to take if we are updating an existing item.
   */
  protected function setRollbackAction(array $id_map, $update_action = MigrateIdMapInterface::ROLLBACK_PRESERVE) {
    // If the entity we're updating was previously migrated by us, preserve the
    // existing rollback action.
    if (isset($id_map['sourceid1'])) {
      $this->rollbackAction = $id_map['rollback_action'];
    }
    else {
      $this->rollbackAction = $update_action;
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function getDestinationModule() {
    if (!empty($this->configuration['destination_module'])) {
      return $this->configuration['destination_module'];
    }
    if (!empty($this->pluginDefinition['destination_module'])) {
      return $this->pluginDefinition['destination_module'];
    }
    if (is_string($this->migration->provider)) {
      return $this->migration->provider;
    }
    else {
      return reset($this->migration->provider);
    }
  }

}