Simple example of custom extractor objects vs existing case class extractors

output.txt

is dino
14
no one
is dino
14
no one

Unapp.scala

object Unapp extends App {

  case class MyClass(age: Int, name: String)

  private object Age {
    def unapply(myClass: MyClass): Option[Int] = myClass match {
      case MyClass(age, _) if (age > 0) => Option(age)
      case _ => None
    }
  }

  private object Name {
    def unapply(myClass: MyClass): Option[String] = myClass match {
      case MyClass(_, name) => Option(name)
      case _ => None
    }
  }

  private object Dino {
    def unapply(myClass: MyClass): Boolean = myClass match {
      case MyClass(53, "Dino") => true
      case _ => false
    }
  }

  val matchMe: MyClass => Unit = {
    case Dino() => println("is dino")
    case Age(age: Int) => println(age)
    case Name(name: String) => println(name)
  }

  matchMe(MyClass(53, "Dino"))
  matchMe(MyClass(14, "Neo"))
  matchMe(MyClass(0, "no one"))

  // without the above custom extractor objects

  val matchMe2: MyClass => Unit = {
    case MyClass(53, "Dino") => println("is dino")
    case MyClass(age, _) if (age > 0) => println(age)
    case MyClass(_, name) => println(name)
  }

  matchMe2(MyClass(53, "Dino"))
  matchMe2(MyClass(14, "Neo"))
  matchMe2(MyClass(0, "no one"))
}