Packages

sealed abstract class Validation[E, A] extends Product with Serializable

Represents either:

  • Success(a), or
  • Failure(e).

Isomorphic to scala.Either and scalaz.\/. The motivation for a Validation is to provide the instance Applicativea that accumulate failures through a scalaz.Semigroup[E].

scalaz.NonEmptyList is commonly chosen as a type constructor for the type E. As a convenience, an alias scalaz.ValidationNel[E] is provided as a shorthand for scalaz.Validation[NonEmptyList[E]], and a method Validation#toValidationNel converts Validation[E] to ValidationNel[E].

Example:

import scalaz._, std.AllInstances._

def parseInt(s: String): Validation[String, Int] =
  try { Success(s.toInt) } catch { case ex: NumberFormatException => Failure(ex.getMessage) }
val V = Applicative[ValidationNel[String, ?]]

val x: ValidationNel[String, Int] =
  V.apply2(parseInt("1.x").toValidationNel, parseInt("1..0").toValidationNel)(_ * _)
  // Failure(NonEmptyList(For input string: "1..0", For input string: "1.x"))
E

The type of the Failure

A

The type of the Success

Source
Validation.scala
Known Subclasses
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  1. Validation
  2. Serializable
  3. Serializable
  4. Product
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Type Members

  1. final class SwitchingValidation[X] extends AnyRef

Abstract Value Members

  1. abstract def canEqual(that: Any): Boolean
    Definition Classes
    Equals
  2. abstract def productArity: Int
    Definition Classes
    Product
  3. abstract def productElement(n: Int): Any
    Definition Classes
    Product

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. def +++(x: ⇒ Validation[E, A])(implicit M1: Semigroup[A], M2: Semigroup[E]): Validation[E, A]

    Sums up values inside validation, if both are success or failure.

    Sums up values inside validation, if both are success or failure. Returns first failure otherwise.

    success(v1) +++ success(v2) → success(v1 + v2)
    success(v1) +++ failure(v2) → failure(v2)
    failure(v1) +++ success(v2) → failure(v1)
    failure(v1) +++ failure(v2) → failure(v1 + v2)
  4. def +|+(x: Validation[E, A])(implicit es: Semigroup[E], as: Semigroup[A]): Validation[E, A]

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each.

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each. Otherwise, return the success. Alias for append

  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def ===(x: Validation[E, A])(implicit EE: Equal[E], EA: Equal[A]): Boolean

    Compare two validations values for equality.

  7. def @\/[EE, AA](k: (\/[E, A]) ⇒ \/[EE, AA]): Validation[EE, AA]

    Run a disjunction function and back to validation again.

    Run a disjunction function and back to validation again. Alias for disjunctioned

  8. def andThen[EE >: E, B](f: (A) ⇒ Validation[EE, B]): Validation[EE, B]
  9. def ap[B](x: ⇒ Validation[E, (A) ⇒ B])(implicit E: Semigroup[E]): Validation[E, B]

    Apply a function in the environment of the success of this validation, accumulating errors.

  10. def append(that: Validation[E, A])(implicit es: Semigroup[E], as: Semigroup[A]): Validation[E, A]

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each.

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each. Otherwise, return the success. Alias for +|+

  11. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  12. def bimap[C, D](f: (E) ⇒ C, g: (A) ⇒ D): Validation[C, D]

    Binary functor map on this validation.

  13. def bitraverse[G[_], C, D](f: (E) ⇒ G[C], g: (A) ⇒ G[D])(implicit arg0: Functor[G]): G[Validation[C, D]]

    Binary functor traverse on this validation.

  14. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  15. def compare(x: Validation[E, A])(implicit OE: Order[E], OA: Order[A]): Ordering

    Compare two validations values for ordering.

  16. def disjunctioned[EE, AA](k: (\/[E, A]) ⇒ \/[EE, AA]): Validation[EE, AA]

    Run a disjunction function and back to validation again.

    Run a disjunction function and back to validation again. Alias for @\/

  17. def ensure(onFailure: ⇒ E)(f: (A) ⇒ Boolean): Validation[E, A]

    Ensures that the success value of this validation satisfies the given predicate, or fails with the given value.

  18. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  19. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  20. def excepting(pf: PartialFunction[A, E]): Validation[E, A]

    Return a Validation formed by the application of a partial function across the success of this value:

    Return a Validation formed by the application of a partial function across the success of this value:

    strings map (_.parseInt excepting { case i if i < 0 => new Exception(s"Int must be positive: $i") })
    Since

    7.0.2

  21. def exists(f: (A) ⇒ Boolean): Boolean

    Return true if this validation is a success value satisfying the given predicate.

  22. def filter(p: (A) ⇒ Boolean)(implicit M: Monoid[E]): Validation[E, A]

    Filter on the success of this validation.

  23. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  24. def findSuccess(that: ⇒ Validation[E, A])(implicit es: Semigroup[E]): Validation[E, A]

    If this is a success, return it; otherwise, if that is a success, return it; otherwise, combine the failures with the specified semigroup.

  25. def fold[X](fail: (E) ⇒ X, succ: (A) ⇒ X): X

    Catamorphism.

    Catamorphism. Run the first given function if failure, otherwise, the second given function.

  26. def foldConst[X](fail: ⇒ X, success: ⇒ X): X

    If this validation is success, return success, otherwise, return fail.

  27. def foldRight[B](z: ⇒ B)(f: (A, ⇒ B) ⇒ B): B

    Fold on the success of this validation.

  28. def forall(f: (A) ⇒ Boolean): Boolean

    Return true if this validation is a failure value or the success value satisfies the given predicate.

  29. def foreach(f: (A) ⇒ Unit): Unit

    Run the side-effect on the success of this validation.

  30. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  31. def getOrElse[AA >: A](x: ⇒ AA): AA

    Return the success value of this validation or the given default if failure.

    Return the success value of this validation or the given default if failure. Alias for |

  32. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  33. def isFailure: Boolean

    Return true if this validation is failure.

  34. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  35. def isSuccess: Boolean

    Return true if this validation is success.

  36. def leftMap[C](f: (E) ⇒ C): Validation[C, A]

    Run the given function on the left value.

  37. def loopFailure[X](success: (A) ⇒ X, failure: (E) ⇒ \/[X, Validation[E, A]]): X

    Spin in tail-position on the failure value of this validation.

  38. def loopSuccess[X](success: (A) ⇒ \/[X, Validation[E, A]], failure: (E) ⇒ X): X

    Spin in tail-position on the success value of this validation.

  39. def map[B](f: (A) ⇒ B): Validation[E, B]

    Map on the success of this validation.

  40. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  41. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  42. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  43. def orElse(x: ⇒ Validation[E, A]): Validation[E, A]

    Return this if it is a success, otherwise, return the given value.

    Return this if it is a success, otherwise, return the given value. Alias for |||

  44. def productIterator: Iterator[Any]
    Definition Classes
    Product
  45. def productPrefix: String
    Definition Classes
    Product
  46. def swap: Validation[A, E]

    Flip the failure/success values in this validation.

    Flip the failure/success values in this validation. Alias for unary_~

  47. def swapped[EE, AA](k: (Validation[A, E]) ⇒ Validation[AA, EE]): Validation[EE, AA]

    Run the given function on this swapped value.

    Run the given function on this swapped value. Alias for ~

  48. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  49. def toDisjunction: \/[E, A]

    Convert to a disjunction.

  50. def toEither: Either[E, A]

    Convert to a core scala.Either at your own peril.

  51. def toIList[AA >: A]: IList[AA]

    Return an empty ilist or an ilist with one element on the success of this validation.

  52. def toList: List[A]

    Return an empty list or a list with one element on the success of this validation.

  53. def toMaybe[AA >: A]: Maybe[AA]

    Return an empty maybe or maybe with the element on the success of this validation.

    Return an empty maybe or maybe with the element on the success of this validation. Useful to sweep errors under the carpet.

  54. def toOption: Option[A]

    Return an empty option or option with one element on the success of this validation.

    Return an empty option or option with one element on the success of this validation. Useful to sweep errors under the carpet.

  55. def toStream: Stream[A]

    Return an empty stream or stream with one element on the success of this validation.

  56. def toString(): String
    Definition Classes
    AnyRef → Any
  57. def toValidationNel: ValidationNel[E, A]

    Wraps the failure value in a scalaz.NonEmptyList

  58. def traverse[G[_], B](f: (A) ⇒ G[B])(implicit arg0: Applicative[G]): G[Validation[E, B]]

    Traverse on the success of this validation.

  59. def unary_~: Validation[A, E]

    Flip the failure/success values in this validation.

    Flip the failure/success values in this validation. Alias for swap

  60. def valueOr[AA >: A](x: (E) ⇒ AA): AA

    Return the success value of this validation or run the given function on the failure.

  61. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  62. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  63. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  64. def |[AA >: A](x: ⇒ AA): AA

    Return the success value of this validation or the given default if failure.

    Return the success value of this validation or the given default if failure. Alias for getOrElse

  65. def |||(x: ⇒ Validation[E, A]): Validation[E, A]

    Return this if it is a success, otherwise, return the given value.

    Return this if it is a success, otherwise, return the given value. Alias for orElse

  66. def ~[EE, AA](k: (Validation[A, E]) ⇒ Validation[AA, EE]): Validation[EE, AA]

    Run the given function on this swapped value.

    Run the given function on this swapped value. Alias for swapped

Deprecated Value Members

  1. def :?>>[X](success: ⇒ X): SwitchingValidation[X]

    If this validation is success, return the given X value, otherwise, return the X value given to the return value.

    If this validation is success, return the given X value, otherwise, return the X value given to the return value.

    Annotations
    @deprecated
    Deprecated

    (Since version 7.3.0) Due to SI-1980, <<?: will always evaluate its left argument; use foldConst instead

  2. def disjunction: \/[E, A]
    Annotations
    @deprecated
    Deprecated

    (Since version 7.3.0) Use toDisjunction

Inherited from Serializable

Inherited from Serializable

Inherited from Product

Inherited from Equals

Inherited from AnyRef

Inherited from Any

Ungrouped