joshua-r2
11/7/2017 - 2:53 PM

Throw

Throw is used to force an exception that would otherwise not be thrown. This comes in handy for making your own logic which shouldn't accept values outside of a given parameter. Like "Try", "Throw" can be passed as a value.

SomeFile
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fun PickaNumberBetweenOneAndOneHundred(number: Int)
{
  if(number !in 1..100){
    throw IllegalArgumentException("It said a number between 1 and 100 you dingus")
  }
}

//Throw as an expression
fun percentConverter(decimal: Long): Long{
val percentage = if(decimal+>0 && decimal<=1){
        decimal*100
        }
      else{
        throw IllegalArgumentException("Decimal must be within bounds of 0 and 1")
        }
    
    
  return percentage    

}

//Using Throw with an Elvis operator

fun printName(person: Person?){

  val name: String = person.name ?: throw IllegalArgumentException("Everyone needs a name ya dingus")
  println(name)
  
}

//Using the Nothing type to not continue beyond a call

fun fail(message: String): Nothing{
  throw IllegalArgumentException(message)
}

fun printDoggoName(name: String?){
  //will not execute beyond this line if null due to Nothing return Type
  val doggoName = name ?: fail("Doggo Name required")
  
  println(doggoName)

}