erikrozendaal

public String negotiateFormat(HttpServletRequest request) {
    String format = request.getParameter("format");
    if (format == null)
        format = getFormatFromUriExtension(request);
    if (format == null)
        format = getFormatFromAcceptHeader(request);
    if (format == null)
        format = "html";
    return format;
}

erikrozendaal

trait AggregateRoot[Event] {
  protected def applyEvent: Event => Unit

  def uncommittedEvents: Iterable[Event] = _uncommittedEvents

  def markCommitted = _uncommittedEvents.clear

  def loadFromHistory(history: Iterable[Event]) = history.foreach(applyEvent)

  protected def record(event: Event) {

erikrozendaal

case class Invoice (
    uncommittedEvents: List[InvoiceEvent],
    id: Int,
    recipient_? : Boolean = false,
    nextItemId: Int = 1,
    items: Map[Int, InvoiceItem] = Map.empty,
    sent_? : Boolean = false,
    paid_? : Boolean = false,
    dueDate: Option[LocalDate] = None)
  extends AggregateRoot[Invoice, InvoiceEvent] {

erikrozendaal

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]
  }
}

erikrozendaal

trait Reaction[+T]
case class Accepted[+T](events: List[Any], result: T) extends Reaction[T]
case class Rejected(message: String) extends Reaction[Nothing]

trait Behavior[+A] {
  protected def apply(events: List[Any]): Reaction[A]

  // [... code omitted ...]

  def reaction = apply(Nil)

erikrozendaal

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

  "support adding invoice items" in {
    val updated = invoice.addItem("Food", "2.95") flatMap (_.addItem("Water", "1.95")) flatMap (_.removeItem(1))

    updated.changes must contain(InvoiceItemAdded(1, InvoiceItem(1, "Food", "2.95"), "2.95"))
    updated.changes must contain(InvoiceItemAdded(1, InvoiceItem(2, "Water", "1.95"), "4.90"))
    updated.changes must contain(InvoiceItemRemoved(1, InvoiceItem(1, "Food", "2.95"), "1.95"))
  }

erikrozendaal

# CQRS+ES Domain DSL

class Symbol
  def snake_case
    to_s.gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2').
      gsub(/([a-z\d])([A-Z])/, '\1_\2').
      tr("-", "_").
      downcase.to_sym
  end

erikrozendaal

import collection.immutable.TreeMap
import util.Random

object TreeMapTest {

  def time(block: => Unit): Double = {
    val start = System.nanoTime()
    block
    val stop = System.nanoTime()
    (stop - start) / 1.0e9

erikrozendaal

import collection.mutable.ArrayBuffer
import collection.immutable.HashMap

object HashMapTest {

  val random = new util.Random(1234)

  def time(block: => Unit): Double = {
    val start = System.nanoTime()
    block

erikrozendaal

# --- !Ups

create table users (
  name text primary key, 
  age int not null);

# --- !Downs
 
drop table users;