Scala example source code file (Try.scala)

This example Scala source code file (Try.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

Learn more about this Scala project at its project page.

Java - Scala tags/keywords

failure, isofunctortemplate, success, throwable, try, tryfunctions, tryinstances, validation, validationnel

The Try.scala Scala example source code

package scalaz
package std

import Isomorphism.{<~>, IsoFunctorTemplate}
import scala.util.{Failure, Success, Try}

trait TryFunctions {
  def cata[A, B](t: Try[A])(success: A => B, failure: Throwable => B): B =
    t match {
      case Success(a) => success(a)
      case Failure(t) => failure(t)
    }

  def toDisjunction[A](t: Try[A]): Throwable \/ A =
    cata(t)(\/.right, \/.left)

  def fromDisjunction[T <: Throwable, A](d: T \/ A): Try[A] =
    d.fold(Failure.apply, Success.apply)

  def toValidation[A](t: Try[A]): Validation[Throwable, A] =
    cata(t)(Validation.success, Validation.failure)

  def toValidationNel[A](t: Try[A]) : ValidationNel[Throwable, A] =
    cata(t)(Validation.success, Validation.failureNel)

  def fromValidation[T <: Throwable, A](v: Validation[T, A]) : Try[A] =
    v.fold(Failure.apply, Success.apply)
}

trait TryInstances {
  import scalaz.std.{`try` => t}

  val tryDisjunctionIso: Try <~> λ[α => Throwable \/ α] =
    new IsoFunctorTemplate[Try, Throwable \/ ?] {
      def to[A](fa: Try[A]) = t.toDisjunction(fa)
      def from[A](ga: Throwable \/ A) = t.fromDisjunction(ga)
    }

  val tryValidationIso: Try <~> λ[α => Validation[Throwable, α]] =
    new IsoFunctorTemplate[Try, Validation[Throwable, ?]] {
      def to[A](fa: Try[A]) = t.toValidation(fa)
      def from[A](v: Validation[Throwable, A]) = t.fromValidation(v)
    }
}

object `try` extends TryFunctions with TryInstances