Code for immutable domain blog part 4

AggregateFactory.scala

trait AggregateFactory[AR <: AggregateRoot[AR, Event], Event] extends EventSourced[Event] {
  def loadFromHistory[T <: AR](history: Iterable[Event]): T = {
    var aggregate = applyEvent(history.head)
    for (event <- history.tail)
      aggregate = aggregate.applyEvent(event)
    aggregate.asInstanceOf[AR].markCommitted.asInstanceOf[T]
  }
}

ApplyEvent.scala

def applyEvent = {
  // [... code omitted ...]
  case event: InvoiceSent => applySent(event)
  // [... code omitted ...]
}

BadCall.scala

Invoice.create(2).changeRecipient(Some("Erik")).pay.send.addItem("Food", 2.95)

DraftInvoice.scala

sealed trait Invoice extends AggregateRoot[Invoice, InvoiceEvent]

case class DraftInvoice(
    uncommittedEvents: List[InvoiceEvent],
    id: Int,
    recipient_? : Boolean = false,
    nextItemId: Int = 1,
    items: Map[Int, InvoiceItem] = Map.empty)
  extends Invoice {
  // [... code omitted ...]
}

NotPayable.scala

"draft invoice" should {
  val invoice: DraftInvoice = Invoice.loadFromHistory(Seq(InvoiceCreated(1)))

  "not be payable" in {
    invoice.pay must throwA[IllegalArgumentException]
  }
}

PaidInvoice.scala

case class PaidInvoice(uncommittedEvents: List[InvoiceEvent]) extends Invoice {
  def markCommitted = copy(uncommittedEvents = Nil)

  def applyEvent = unhandled
}

Send.scala

def send: SentInvoice = {
  require(readyToSend_?, "recipient and items must be specified before sending")
  val now = new LocalDate
  applySent(InvoiceSent(id, sentDate = now, dueDate = now.plusDays(14)))
}

private def applySent(event: InvoiceSent) = new SentInvoice(event :: uncommittedEvents, id, event.dueDate)