learning scala implicit class

最新推荐文章于 2025-09-12 12:19:17 发布

转载最新推荐文章于 2025-09-12 12:19:17 发布 · 61 阅读

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原文链接：http://www.cnblogs.com/lianghong881018/p/11175024.html

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#scala

隐式类可以用来扩展对象的功能非常方便

example:

object ImplicitClass_Tutorial extends App {

  println("Step 1: How to define a case class to represent a Donut object")
  case class Donut(name: String, price: Double, productCode: Option[Long] = None)



  println("\nStep 2: How to create instances or objects for the Donut case class")
  val vanillaDonut: Donut = Donut("Vanilla", 1.50)
  println(s"Vanilla donut name = ${vanillaDonut.name}")
  println(s"Vanilla donut price = ${vanillaDonut.price}")
  println(s"Vanilla donut produceCode = ${vanillaDonut.productCode}")



  println("\nStep 3: How to define an implicit class to augment or extend the Donut object with a uuid field")
  object DonutImplicits{
    implicit class AugmentedDonut(donut: Donut) {
      def uuid: String = s"${donut.name} - ${donut.productCode.getOrElse(12345)}"
    }
  }



  println("\nStep 4: How to import and use the implicit class AugmentedDonut from Step 3")
  import DonutImplicits._
  println(s"Vanilla donut uuid = ${vanillaDonut.uuid}")
}