将类型从A转换为B,反之亦然Scala

时间:2013-08-08 18:27:29

标签: scala functional-programming scalaz

我们的Web服务接口的一部分,我们创建了更轻量级的面向客户端的API,这些API不依赖于任何特定的平台/供应商API。

现在,这些服务特征的impl必须将这些承载传入数据的平台不可知类型转换为供应商特定类型,以便impl方法继续按原样工作。请注意,我们无法更改供应商API上的任何代码。我想我们必须创建某种适配器/转换API,可以双向进行这种类型的转换。一些供应商类型非常神秘。例如较轻的服务接口可以具有包含所有数据的展平类型,而供应商API具有可以获取输入数据的分层类型等。返回类型的情况也是如此。在Scala中实现这一目标的最佳方法是什么?

编辑:示例

case class A(var1,var2,var3,var4,var5,var6)

public Class B{

  private C c;
  private D d;

}

案例类是一个扁平化结构,需要所有数据,而另一方面,来自类A类的数据将填充为B(var2,var3),C(var4,var5),D(var6)等。我忘了提到供应商API都是基于Java的。

谢谢,

1 个答案:

答案 0 :(得分:0)

我想说你可以利用“Pimping”模式在两者之间来回走动。这是我在我的应用程序中使用的一大块东西。我只转换一种方式,但你可以看到另一种隐含的方式,你可以实现逻辑回到原始/你的格式。

// implicits for pimping 
implicit def pimpUser(user: User) = PimpedUser(user)
implicit def pimpLimitedViewUser(user: LimitedViewUser) = PimpedLimitedViewUser(user)

@entity
case class User(@serializer(classOf[UUIDOptionSerializer]) @id @column(name = "id") override val id: Option[UUID] = None,
                @serializer(classOf[DateOptionSerializer]) @column(name = "created_on") override val createdOn: Option[Date] = None,
                @serializer(classOf[DateOptionSerializer]) @column(name = "modified_on") override val modifiedOn: Option[Date] = None,
                @serializer(classOf[StringOptionSerializer]) @column(name = "first_name") firstName: Option[String] = None,
                @serializer(classOf[StringOptionSerializer]) @column(name = "last_name") lastName: Option[String] = None,
                @serializer(classOf[StringOptionSerializer]) @column(name = "email_address") emailAddress: Option[String] = None,
                @serializer(classOf[StringOptionSerializer]) @column(name = "password_salt") passwordSalt: Option[String] = None,
                @serializer(classOf[StringOptionSerializer]) @column(name = "password_hash") passwordHash: Option[String] = None,
                @serializer(classOf[IntOptionSerializer]) @column(name = "extension") extension: Option[Int] = None,
                devices: Set[Device] = Set.empty,
                @serializer(classOf[RingModeSerializer]) @column(name = "ring_mode") ringMode: RingMode = Waterfall) extends IdBaseEntity[UUID] {
  def this() = this(None, None, None, None, None, None, None, None, None, Set.empty[Device], Waterfall)

  override def equals(other: Any): Boolean =
    other match {
      case that: User => (that canEqual this) && (this.id match {
        case Some(uuid) => that.id match {
          case Some(thatUuid) => uuid == thatUuid
          case None => false
        }
        case None => false
      })
      case _ => false
    }

  override def hashCode: Int = this.id match {
    case Some(uuid) => 41 * (41 + uuid.hashCode())
    case None => super.hashCode
  }

  override def canEqual(other: Any): Boolean = other.isInstanceOf[User]

  def asAvailable: User = {
    User.devices.set(this)(devices.map(_.asAvailable))
  }

  def asUnavailable: User = {
    User.devices.set(this)(devices.map(_.asUnavailable))
  }
}

object User {
  implicit val userIso = Iso.hlist(User.apply _, User.unapply _)

  val id = Lens[User] >> _0
  val createdOn = Lens[User] >> _1
  val modifiedOn = Lens[User] >> _2
  val firstName = Lens[User] >> _3
  val lastName = Lens[User] >> _4
  val emailAddress = Lens[User] >> _5
  val passwordSalt = Lens[User] >> _6
  val passwordHash = Lens[User] >> _7
  val extension = Lens[User] >> _8
  val devices = Lens[User] >> _9
  val ringMode = Lens[User] >> _10
}

case class LimitedViewUser(id: Option[UUID], createdOn: Option[Date], modifiedOn: Option[Date], firstName: Option[String], lastName: Option[String]) {
  def this(user: User) = this(user.id, user.createdOn, user.modifiedOn, user.firstName, user.lastName)
}

case class PimpedUser(underlying: User) {
  def limited = LimitedViewUser(underlying)
}

case class PimpedLimitedViewUser(underlying: LimitedViewUser) {
  def normal = /* do something here to transform back to yours/the normal one */
}

// As long as those implicits are brought into scope, you will be able to do this:

val user: User = /* ... */
val limitedViewUser: LimitedViewUser = user.limited
val normalUser: User = limitedViewUser.normal