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Scala with DDD
- 6. ところで
- 8. テーブル？
- 9. UI？
- 10. DDDでは(ドメイン)モデル
- 11. なんで？
- 12. 詳しくはこちら？
- 13. というのは、 冗談です
- 16. I/F Domain Model
- 17. 問題の領域＝ ドメイン
- 18. ボクらのハンタードメイン
- 21. 落とし物を拾うシーン
- 24. ハンターが落とし物を拾い、 アイテムとして所持する。 Hunter 1 0..* LostMatter trait Item trait LostMatter extends Item trait Hunter { val items: Seq[Item] def take(lostMatter: LostMatter): Try[Hunter] }
- 25. ドメインの語彙＝ ユビキタス言語
- 26. シナリオ 実装 モデル
- 29. モデルと実装
- 32. trait Entity[ID <: Identity[_]] { ! /** エンティティの識別子。 */ val identity: ID ! override final def hashCode: Int = 31 * identity.## ! override final def equals(obj: Any): Boolean = obj match { case that: Entity[_] => identity == that.identity case _ => false } ! }
- 33. trait Identity[+A] extends Serializable { ! def value: A ! } ! object EmptyIdentity extends Identity[Nothing] { ! def value = throw EmptyIdentityException() ! override def equals(obj: Any): Boolean = EmptyIdentity eq obj ! override def hashCode(): Int = 31 * 1 ! override def toString = "EmptyIdentity" }
- 34. case class User(id: Int, firstName: String, lastName: String) ! val l = List( User(1, "Yutaka", “Yamashiro"), User(2, "Junchi", “Kato") ) l.exists(_ == User(1, "Yutaka", "Yamashiro")) // true
- 35. // 値表現としての山城さんが改名されてしまったら見分けられない val l = List( User(1, "Yutaka", “Yamashiro"). copy(lastName = “Hogeshiro"), User(2, "Junchi", "Kato")) l.exists(_ == User(1, "Yutaka", "Yamashiro")) // false ! // この操作は危険。オブジェクトを取り違える可能性。 User(1, "Yutaka", "Yamashiro").copy(id = 2)
- 36. class User(val id: Int, val firstName: String, val lastName: String) { override def equals(obj: Any): Boolean = obj match { case that: User => id == that.id case _ => false } override def hashCode = 31 * id.## // 識別子は更新できない def copy(firstName: String = this.firstName, lastName: String = this.lastName) = new User(firstName, lastName) } object User { def apply(…): User = … }
- 37. // 見つけられる val l = List( User(1, "Yutaka", "Hogeshiro"), User(2, "Junchi", "Kato")) l.exists(_ == User(1, "Yutaka", "Yamashiro")) // true
- 38. case class HunterId(value: UUID) extends Identity[UUID] ! class Hunter( val identity: HunterId, val name: String, val rank: Int, // ... ) extends Entity[HunterId] { // ... }
- 40. sealed trait Item { val name: String def beUsedBy(hunter: Hunter): Try[Hunter] } case class Analepticum() extends Item { val name = "analepticum" def beUsedBy(hunter: Hunter): Try[Hunter] = { // hunterを回復させる } } case class Antidote() extends Item { val name = "antidote" def beUsedBy(hunter: Hunter): Try[Hunter] = { // hunterを解毒させる } }
- 41. class Hunter( val identity: HunterId, val name: String, val rank: Int, val items: Set[Item] ) extends Entity[HunterId] { ! def use(item: Item): Try[Hunter] = { require(items.exists(_ == item)) item.beUsedBy(hunter) } ! }
- 44. ライフサイクルの管理
- 48. Repository DAO Repository on Memory on Memcached on DB DAO on API
- 49. どんなI/Fがあるか def resolve(identity: ID) (implicit ctx: EntityIOContext): Future[E] ! def store(entity: E) (implicit ctx: EntityIOContext): Future[(R, E)] ! def delete(identity: ID) (implicit ctx: EntityIOContext): Future[(R, E)] ! def resolveChunk(index: Int, maxEntities: Int) (implicit ctx: EntityIOContext): Future[EntitiesChunk[ID, E]] ! // toList, toSetは メモリ版の実装のみ。 def toList: Future[List[E]] def toSet: Future[Set[E]]
- 51. ! protected val storage: AsyncRepository[ID, E] ! protected val cache: AsyncRepository[ID, E] ! def resolve(identity: ID) (implicit ctx: EntityIOContext): Future[E] = { implicit val executor = getExecutionContext(ctx) cache.resolve(identity).recoverWith { case ex: EntityNotFoundException => for { entity <-‐ storage.resolve(identity) (_, result) <-‐ cache.store(entity) } yield { result } } }
- 52. def filterByPredicate(predicate: E => Boolean, index: Option[Int] = None, maxEntities: Option[Int] = None) (implicit ctx: EntityIOContext): Future[EntitiesChunk[ID, E]] ! def filterByCriteria(criteria: Criteria, index: Option[Int] = None, maxEntities: Option[Int] = None) (implicit ctx: EntityIOContext): Future[EntitiesChunk[ID, E]] ! trait CriteriaValue[A] { val name: String val operator: OperatorType.Value val value: A def asString: String } ! trait Criteria { protected val criteriaValues: List[CriteriaValue[_]] def asString: String }
- 53. val repository: HunterRepository = HunterRepository(RepositoryType.Memory) // or RepositoryType.Memcached ! val hunter = new Hunter(EmptyIdentity, ...) ! val updateTime = for { (newRepos, newEntity) <-‐ repository.store(hunter) // def store(entity: E): Try[(R, E)] hunter <-‐ newRepos.resolve(newEntity.identity) // def resolve(identity: ID): Try[E] } yield { hunter.updateTime }
- 54. val repository: HunterRepository = HunterRepository(RepositoryType.JDBC) ! val hunter = new Hunter(EmptyIdentity, ...) ! // def withTransaction[T](f: (DBSession) => T): T val updateTime = UnitOfWork.withTransaction { tx => implicit ctx = EntityIOContext(tx) for { (newRepos, newEntity) <-‐ repository.store(hunter) // def store(entity: E) // (implicit ctx: EntityIOContext): Try[(R, E)] hunter <-‐ newRepos.resolve(newEntity.identity) // def resolve(identity: ID) // (implicit ctx: EntityIOContext): Try[E] } yield { hunter.updateTime } }
- 56. val repository: HunterRepository = HunterRepository(RepositoryType.JDBC) ! val hunter = new Hunter(EmptyIdentity, ...) ! // def withTransaction[T](f: (DBSession) => Future[T]): Future[T] val updateTime = UnitOfWork.withTransaction { tx => implicit ctx = EntityIOContext(tx) for { (newRepos, newEntity) <-‐ repository.store(hunter) // def store(entity: E) // (implicit ctx: EntityIOContext): Future[(R, E)] hunter <-‐ newRepos.resolve(newEntity.identity) // def resolve(identity: ID) // (implicit ctx: EntityIOContext): Future[E] } yield { hunter.updateTime } }
- 57. def withTransaction[A](op: (DBSession) => Future[A]) (implicit executor: ExecutionContext): Future[A] = { Future(ConnectionPool.borrow()).flatMap { connection => val db = DB(connection) Future(db.newTx).flatMap { tx => Future(tx.begin()).flatMap { _ => op(db.withinTxSession(tx)) }.andThen { case Success(_) => tx.commit() case Failure(_) => tx.rollback() } }.andThen { case _ => connection.close() } } }
- 59. class HunterController(hunterRepository: HunterRepository) extends ControllerSupport { def createHunter = SimpleAction { request => val params = parseJson(request) val formValidation = CreateForm.validate(params) formValidation.fold(validationErrorHandler, { case form => UnitOfWork.withSession { implicit session => hunterRepository. store(form.asEntity).flatMap { case (_, entity) => responseBuilder. withJValue(entity.asJValue).toFuture } } }) } }
- 60. class HunterController(hunterRepository: HunterRepository) extends ControllerSupport { def transferItems(from: HunterId, to: HunterId, itmes: Seq[Item]) = SimpleAction { request => UnitOfWork.withSession { implicit session => for { toHunter <-‐ hunterRepository.resolve(to) fromHunter <-‐ hunterRepository.resolve(from) _ <-‐ fromHunter.transerItems(items, toHunter) } yield { createResponse() } } } }
- 61. やってみて思ったこと
- 63. Play2 with DDD Controller Batch or ??? Entity VO Domain Repository Service ScalikeJDBC Anorm Play2
- 65. ありがとございました。