Standard Library Utilities

Either Fallback

Represent success or a named error without throwing.

Either Fallback

EitherFallback.scala 
object Main {
  def main(args: Array[String]): Unit = {
    val ok = 
    val result: Either[String, Int] = if (ok) Right(42) else Left("missing")
    val value = result.getOrElse(0)
    val status = if (result.isRight) "ok" else "fallback"

    println("status=" + status)
    println("value=" + value)
  }
}

object Main {
  def main(args: Array[String]): Unit = {
    val ok = 
    val result: Either[String, Int] = if (ok) Right(42) else Left("missing")
    val value = result.getOrElse(0)
    val status = if (result.isRight) "ok" else "fallback"

    println("status=" + status)
    println("value=" + value)
  }
}
either `Either[String, Int]` stores either an error label on the left or a useful value on the right. `getOrElse` supplies a fallback when the value is missing.