Question

鉴于以下情况

abstract class Animal {/***/}
class Dog(s : String) extends Animal {/***/}
class Cat(s :String) extends Animal {/***/}

 class C() {
  val animal: Animal = new Dog(name)
  private def name = "name for animal that C knows how to calculate"
}

如何向C提供Animal实例，而不是创建它的C？

可以执行类似

的操作

class B(f : String => Animal) {
  val animal: Animal = f(name)
  private def name = "name for animal that B knows how to calculate"
}

然后允许我

val bWithDog = new B((name: String) => new Dog(name))
val bWithCat = new B((name: String) => new Cat(name))

这是我的目标但这是一个干净的解决方案吗？或者将Animal提供给C是没有意义的，因为只有C知道如何计算它的名字？

Answer 1

class C(val animal: Animal) {
 private def name = "name for animal that C knows how to calculate"
}
new C(new Dog("fiddo"))

构造函数参数有什么问题？

Scala：依赖注入

1 个答案: