Question

更新：更改了示例以反映我当前的情况

相当新的解除，我正在尝试为我的应用程序创建一个模型。由于我想保持DRY的精神，我想使用trait mixins来指定我模型中的一些字段。例如，我有一个Person特征，我将其混合到我的Employee类：

trait Person[T <: LongKeyedMapper[T]] extends LongKeyedMapper[T]{
  self: T =>
  object firstName extends MappedString[T](this, 50)
  object lastName extends MappedString[T](this, 50)
  object civicRegNumber extends MappedString[T](this, 12)
}

class Employee extends IdPK with OneToMany[Long, Employee] with Person[Employee] {
  def getSingleton = Employee

  object contactInfos extends MappedOneToMany(EmployeeContactInfo, EmployeeContactInfo.person) 
}

object Employee extends Employee with LongKeyedMetaMapper[Employee]

可以看出，我在Employee中有一个contactInfos多对一映射。它看起来像：

trait PersonContactInfo[T <: LongKeyedMapper[T],P <: Person[P]] extends LongKeyedMapper[T] {
  self: T =>
  object email extends MappedEmail[T](this, 80)
  def personMeta:P with LongKeyedMetaMapper[P]
  object person extends LongMappedMapper[T,P](this, personMeta)
}

class EmployeeContactInfo extends IdPK with PersonContactInfo[EmployeeContactInfo, Employee] {
  def getSingleton = EmployeeContactInfo
  val personMeta = Employee

}
object EmployeeContactInfo extends  EmployeeContactInfo with LongKeyedMetaMapper[EmployeeContactInfo]

这似乎有效，但我想将contactInfos对象移动到我的Person特征中。但是，我无法弄清楚如何实现这一点......是否可以从特征继承OneToMany映射？欢迎任何帮助！

Answer 1

经过几次尝试后，我通过将执行Person的OneToMany映射的特征分离到PersonContactInfo来实现此功能。这就是它现在的样子

trait Person[T <: Person[T]] extends LongKeyedMapper[T]{
  self: T =>
  object firstName extends MappedString[T](this, 50)
  object lastName extends MappedString[T](this, 50)
  object civicRegNumber extends MappedString[T](this, 12)
}

trait PersonToPersonContacts[P <: Person[P], PCI <: PersonContactInfo[PCI, P]] extends OneToMany[Long,P] {
  self: P =>
  def contactInfoMeta:LongKeyedMetaMapper[PCI] with PCI
  object contactInfos extends MappedOneToMany(contactInfoMeta, contactInfoMeta.person)
}

class Employee extends IdPK with Person[Employee]  with PersonToPersonContacts[Employee, EmployeeContactInfo] {
  def getSingleton = Employee
  override def contactInfoMeta = EmployeeContactInfo
}
object Employee extends Employee with LongKeyedMetaMapper[Employee]

我的PersonContactInfo现在看起来像：

trait PersonContactInfo[T <: LongKeyedMapper[T],P <: Person[P]] extends LongKeyedMapper[T] {
  self: T =>
  object email extends MappedEmail[T](this, 80)
  def personMeta:P with LongKeyedMetaMapper[P]
  object person extends LongMappedMapper[T,P](this, personMeta)
}

class EmployeeContactInfo extends IdPK with PersonContactInfo[EmployeeContactInfo, Employee] {
  def getSingleton = EmployeeContactInfo

  val personMeta = Employee

}
object EmployeeContactInfo extends  EmployeeContactInfo with LongKeyedMetaMapper[EmployeeContactInfo]

仍然不确定这是否是解决这个问题的方法，但是ity完成了这项工作：）

提升映射器 - 使用OneToMany映射的特征

1 个答案: