FutureEitherTxBoundary.scala

FutureEitherTxBoundary.scala

object Sample {

  implicit def futureEitherTxBoundary[A, B](implicit ec: ExecutionContext): TxBoundary[Future[Either[A, B]]] = new TxBoundary[Future[Either[A, B]]] {

    def finishTx(result: Future[Either[A, B]], tx: Tx): Future[Either[A, B]] = {
      onFinishTx(result) {
        case Success(Right(_)) => tx.commit()
        case Success(Left(_))  => tx.rollback()
        case Failure(_)        => tx.rollback()
      }
    }

    override def closeConnection(result: Future[Either[A, B]], doClose: () => Unit): Future[Either[A, B]] =
      onFinishTx(result)(_ => doClose())
  }

  // copy from ScalikeJDBC since these are private.
  /**
    * Applies an operation to finish current transaction to the result.
    * When the operation throws some exception, the exception will be returned without fail.
    */
  private def doFinishTx[A](result: Try[A])(doFinish: Try[A] => Unit): Try[A] =
    scala.util.Try(doFinish(result)).transform(
      _ => result,
      finishError =>
        Failure(result match {
          case Success(_) => finishError
          case Failure(resultError) =>
            resultError.addSuppressed(finishError)
            resultError
        }))

  /**
    * Applies an operation to finish current transaction to the Future value which holds the result.
    * When the operation throws some exception, the exception will be returned without fail.
    */
  private def onFinishTx[A](resultF: Future[A])(doFinish: Try[A] => Unit)(implicit ec: ExecutionContext): Future[A] = {
    val p = Promise[A]
    resultF.onComplete(result => p.complete(doFinishTx(result)(doFinish)))
    p.future
  }

}