Interface Validation<E,T>

Type Parameters:

E - the type of values in the case of invalid

T - the type of values in the case of valid

All Superinterfaces:

Iterable<T>, Serializable, Value<T>

All Known Implementing Classes:

Validation.Invalid, Validation.Valid

public interface Validation<E,T>
extends Value<T>, Serializable

An implementation similar to Scalaz's Validation control.

The Validation type is an applicative functor, not a Monad. While a Monad short-circuits on the first error, an applicative functor accumulates all errors, making it particularly useful for validation scenarios where all errors should be reported.

// Validation construction:

// Valid
Validation<String, Integer> valid = Validation.valid(5);

// Invalid
Validation<List<String>, Integer>invalid = Validation.invalid(List.of("error1", "error2"));

// Validation combination:

Validation<String, String> valid1 = Validation.valid("John");
Validation<String, Integer> valid2 = Validation.valid(5);
Validation<String, Option<String>> valid3 = Validation.valid(Option.of("123 Fake St."));
Function3<String, Integer, Option<String>, Person> f = ...;

Validation<List<String>, String> result =
    valid1.combine(valid2).ap((name, age) -> "Name: " + name + " Age: " + age);

Validation<List<String>, Person> result2 =
    valid1.combine(valid2).combine(valid3).ap(f);

// Another way to combine validations:
Validation<List<String>, Person> result3 =
    Validation.combine(valid1, valid2, valid3).ap(f);

See Also:

• Scalaz Validation source

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	Validation.Builder<E,T1,T2>	A builder that holds two Validation instances, used for combining validations and applying functions that take two arguments.
static final class	Validation.Builder3<E,T1,T2,T3>	A builder that holds three Validation instances, used for combining validations and applying functions that take three arguments.
static final class	Validation.Builder4<E,T1,T2,T3,T4>	A builder that holds four Validation instances, used for combining validations and applying functions that take four arguments.
static final class	Validation.Builder5<E,T1,T2,T3,T4,T5>	A builder that holds five Validation instances, used for combining validations and applying functions that take five arguments.
static final class	Validation.Builder6<E,T1,T2,T3,T4,T5,T6>	A builder that holds six Validation instances, used for combining validations and applying functions that take six arguments.
static final class	Validation.Builder7<E,T1,T2,T3,T4,T5,T6,T7>	A builder that holds seven Validation instances, used for combining validations and applying functions that take seven arguments.
static final class	Validation.Builder8<E,T1,T2,T3,T4,T5,T6,T7,T8>	A builder that holds eight Validation instances, used for combining validations and applying functions that take eight arguments.
static final class	Validation.Invalid<E,T>	An invalid Validation
static final class	Validation.Valid<E,T>	A valid Validation

Field Summary

Fields

Modifier and Type	Field	Description
static final long	serialVersionUID	The serial version UID for serialization.

Method Summary

Modifier and Type	Method	Description
default <U> Validation<Seq<E>,U>	ap(@NonNull Validation<Seq<E>, ? extends Function<? super T, ? extends U>> validation)	Applies a validation containing a function to this validation's value, combining errors if both are invalid.
default <E2,T2> Validation<E2,T2>	bimap(@NonNull Function<? super E, ? extends E2> errorMapper, @NonNull Function<? super T, ? extends T2> valueMapper)	Whereas map only performs a mapping on a valid Validation, and mapError performs a mapping on an invalid Validation, bimap allows you to provide mapping actions for both, and will give you the result based on what type of Validation this is.
static <E,T1,T2> Validation.Builder<E,T1,T2>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2)	Combines two Validations into a Validation.Builder.
static <E,T1,T2,T3> Validation.Builder3<E,T1,T2,T3>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2, @NonNull Validation<E,T3> validation3)	Combines three Validations into a Validation.Builder3.
static <E,T1,T2,T3,T4> Validation.Builder4<E,T1,T2,T3,T4>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2, @NonNull Validation<E,T3> validation3, @NonNull Validation<E,T4> validation4)	Combines four Validations into a Validation.Builder4.
static <E,T1,T2,T3,T4,T5> Validation.Builder5<E,T1,T2,T3,T4,T5>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2, @NonNull Validation<E,T3> validation3, @NonNull Validation<E,T4> validation4, @NonNull Validation<E,T5> validation5)	Combines five Validations into a Validation.Builder5.
static <E,T1,T2,T3,T4,T5,T6> Validation.Builder6<E,T1,T2,T3,T4,T5,T6>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2, @NonNull Validation<E,T3> validation3, @NonNull Validation<E,T4> validation4, @NonNull Validation<E,T5> validation5, @NonNull Validation<E,T6> validation6)	Combines six Validations into a Validation.Builder6.
static <E,T1,T2,T3,T4,T5,T6,T7> Validation.Builder7<E,T1,T2,T3,T4,T5,T6,T7>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2, @NonNull Validation<E,T3> validation3, @NonNull Validation<E,T4> validation4, @NonNull Validation<E,T5> validation5, @NonNull Validation<E,T6> validation6, @NonNull Validation<E,T7> validation7)	Combines seven Validations into a Validation.Builder7.
static <E,T1,T2,T3,T4,T5,T6,T7,T8> Validation.Builder8<E,T1,T2,T3,T4,T5,T6,T7,T8>	combine(@NonNull Validation<E,T1> validation1, @NonNull Validation<E,T2> validation2, @NonNull Validation<E,T3> validation3, @NonNull Validation<E,T4> validation4, @NonNull Validation<E,T5> validation5, @NonNull Validation<E,T6> validation6, @NonNull Validation<E,T7> validation7, @NonNull Validation<E,T8> validation8)	Combines eight Validations into a Validation.Builder8.
default <U> Validation.Builder<E,T,U>	combine(Validation<E,U> validation)	Combines two Validations to form a Validation.Builder, which can then be used to perform further combines, or apply a function to it in order to transform the Validation.Builder into a Validation.
static <E,T> Validation<E,T>	cond(boolean test, @NonNull T valid, @NonNull E error)	Decides which Validation<E, T> to return, depending on the test value - if it's true, the result will be a Validation.Valid, if it's false - the result will be a Validation.Invalid
static <E,T> Validation<E,T>	cond(boolean test, @NonNull Supplier<? extends T> valid, @NonNull Supplier<? extends E> error)	Decides which Validation<E, T> to return, depending on the test value - if it's true, the result will be a Validation.Valid, if it's false - the result will be a Validation.Invalid
boolean	equals(Object o)	Clarifies that values have a proper equals() method implemented.
default Option<Validation<E,T>>	filter(@NonNull Predicate<? super T> predicate)	Filters this Validation by testing a predicate on the value.
default <U> Validation<E,U>	flatMap(@NonNull Function<? super T, ? extends Validation<E, ? extends U>> mapper)	FlatMaps the value of this Validation if it is valid, otherwise returns this Invalid.
default <U> U	fold(@NonNull Function<? super E, ? extends U> ifInvalid, @NonNull Function<? super T, ? extends U> ifValid)	Transforms this Validation to a value of type U.
default void	forEach(@NonNull Consumer<? super T> action)	Performs the given action for the value contained in Valid, or does nothing if this is an Invalid.
static <E,T> Validation<E,T>	fromEither(@NonNull Either<E,T> either)	Creates a Validation of an Either.
static <T> Validation<Throwable, T>	fromTry(@NonNull Try<? extends T> t)	Creates a Validation of an Try.
T	get()	Gets the value of this Validation if is a Valid or throws if this is an Invalid.
E	getError()	Gets the error of this Validation if it is an Invalid or throws if this is a Valid.
default T	getOrElseGet(@NonNull Function<? super E, ? extends T> other)	Gets the value if it is a Valid or an value calculated from the error.
int	hashCode()	Clarifies that values have a proper hashCode() method implemented.
static <E,T> Validation<E,T>	invalid(E error)	Creates an Validation.Invalid that contains the given error.
default boolean	isAsync()	A Validation's value is computed synchronously.
default boolean	isEmpty()	Checks, this Value is empty, i.e.
boolean	isInvalid()	Check whether this is of type Invalid
default boolean	isLazy()	A Validation's value is computed eagerly.
default boolean	isSingleValued()	States whether this is a single-valued type.
boolean	isValid()	Check whether this is of type Valid
default @NonNull Iterator<T>	iterator()	Returns a rich io.vavr.collection.Iterator.
default <U> Validation<E,U>	map(@NonNull Function<? super T, ? extends U> f)	Maps the underlying value to a different component type.
default <U> Validation<U,T>	mapError(@NonNull Function<? super E, ? extends U> f)	Applies a function f to the error of this Validation if this is an Invalid.
static <E,T> Validation<E,T>	narrow(Validation<? extends E, ? extends T> validation)	Narrows a widened Validation<? extends E, ? extends T> to Validation<E, T> by performing a type-safe cast.
default Validation<E,T>	orElse(@NonNull Validation<? extends E, ? extends T> other)	Returns this Validation if it is valid, otherwise return the alternative.
default Validation<E,T>	orElse(@NonNull Supplier<Validation<? extends E, ? extends T>> supplier)	Returns this Validation if it is valid, otherwise return the result of evaluating supplier.
default Validation<E,T>	peek(@NonNull Consumer<? super T> action)	Performs the given action on the first element if this is an eager implementation.
static <E,T> Validation<Seq<E>,Seq<T>>	sequence(@NonNull Iterable<? extends Validation<? extends Seq<? extends E>, ? extends T>> values)	Reduces many Validation instances into a single Validation by transforming an Iterable<Validation<? extends T>> into a Validation<Seq<T>>.
default Validation<T,E>	swap()	Flip the valid/invalid values for this Validation.
default Either<E,T>	toEither()	Converts this Validation to an Either.
String	toString()	Clarifies that values have a proper toString() method implemented.
static <E,T,U> Validation<Seq<E>,Seq<U>>	traverse(@NonNull Iterable<? extends T> values, @NonNull Function<? super T, ? extends Validation<? extends Seq<? extends E>, ? extends U>> mapper)	Maps the values of an iterable to a sequence of mapped values into a single Validation by transforming an Iterable<? extends T> into a Validation<Seq<U>>.
static <E,T> Validation<E,T>	valid(T value)	Creates a Validation.Valid that contains the given value.

Methods inherited from interface Value

collect, collect, contains, corresponds, eq, exists, forAll, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, mapTo, mapToVoid, out, out, spliterator, stderr, stdout, stringPrefix, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Field Details

serialVersionUID

static final long serialVersionUID

The serial version UID for serialization.

See Also:

• Constant Field Values

Method Details

valid

static <E,T> Validation<E,T> valid(T value)

Creates a Validation.Valid that contains the given value.

Type Parameters:

E - type of the error

T - type of the given value

Parameters:

value - A value

Returns:

Valid(value)

invalid

static <E,T> Validation<E,T> invalid(E error)

Creates an Validation.Invalid that contains the given error.

Type Parameters:

E - type of the given error

T - type of the value

Parameters:

error - An error

Returns:

Invalid(error)

Throws:

NullPointerException - if error is null

fromEither

static <E,T> Validation<E,T> fromEither(@NonNull Either<E,T> either)

Creates a Validation of an Either.

Type Parameters:

E - error type

T - value type

Parameters:

either - An Either

Returns:

A Valid(either.get()) if either is a Right, otherwise Invalid(either.getLeft()).

Throws:

NullPointerException - if either is null

fromTry

static <T> Validation<Throwable, T> fromTry(@NonNull Try<? extends T> t)

Creates a Validation of an Try.

Type Parameters:

T - type of the valid value

Parameters:

t - A Try

Returns:

A Valid(t.get()) if t is a Success, otherwise Invalid(t.getCause()).

Throws:

NullPointerException - if t is null

sequence

static <E,T> Validation<Seq<E>,Seq<T>> sequence(@NonNull Iterable<? extends Validation<? extends Seq<? extends E>, ? extends T>> values)

Reduces many Validation instances into a single Validation by transforming an Iterable<Validation<? extends T>> into a Validation<Seq<T>>.

Type Parameters:

E - value type in the case of invalid

T - value type in the case of valid

Parameters:

values - An iterable of Validation instances.

Returns:

A valid Validation of a sequence of values if all Validation instances are valid or an invalid Validation containing an accumulated List of errors.

Throws:

NullPointerException - if values is null

traverse

static <E,T,U> Validation<Seq<E>,Seq<U>> traverse(@NonNull Iterable<? extends T> values,
 @NonNull Function<? super T, ? extends Validation<? extends Seq<? extends E>, ? extends U>> mapper)

Maps the values of an iterable to a sequence of mapped values into a single Validation by transforming an Iterable<? extends T> into a Validation<Seq<U>>.

Type Parameters:

E - The mapped error value type.

T - The type of the given values.

U - The mapped valid value type.

Parameters:

values - An Iterable of values.

mapper - A mapper of values to Validations

Returns:

A Validation of a Seq of results.

Throws:

NullPointerException - if values or f is null.

narrow

static <E,T> Validation<E,T> narrow(Validation<? extends E, ? extends T> validation)

Narrows a widened Validation<? extends E, ? extends T> to Validation<E, T> by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.

Type Parameters:

E - type of error

T - type of valid value

Parameters:

validation - A Validation.

Returns:

the given validation instance as narrowed type Validation<E, T>.

cond

static <E,T> Validation<E,T> cond(boolean test,
 @NonNull Supplier<? extends T> valid,
 @NonNull Supplier<? extends E> error)

Decides which Validation<E, T> to return, depending on the test value - if it's true, the result will be a Validation.Valid, if it's false - the result will be a Validation.Invalid

Type Parameters:

E - Type of error

T - Type of valid value

Parameters:

test - A boolean value to evaluate

valid - A Supplier<? extends T> supplier of valid value, called if test is true

error - A Supplier<? extends E> supplier of error, called if test is false

Returns:

Validation<E, T> with valid value or error, depending on the test condition evaluation

Throws:

NullPointerException - if any of the arguments is null

cond

static <E,T> Validation<E,T> cond(boolean test,
 @NonNull T valid,
 @NonNull E error)

Decides which Validation<E, T> to return, depending on the test value - if it's true, the result will be a Validation.Valid, if it's false - the result will be a Validation.Invalid

Type Parameters:

E - Type of error

T - Type of valid value

Parameters:

test - A boolean value to evaluate

valid - A T valid value, called if test is true

error - An E error value, called if test is false

Returns:

Validation<E, T> with valid value or error, depending on the test condition evaluation

Throws:

NullPointerException - if any of the arguments is null

combine

static <E,T1,T2> Validation.Builder<E,T1,T2> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2)

Combines two Validations into a Validation.Builder.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

Parameters:

validation1 - first validation

validation2 - second validation

Returns:

an instance of Builder<E,T1,T2>

Throws:

NullPointerException - if validation1 or validation2 is null

combine

static <E,T1,T2,T3> Validation.Builder3<E,T1,T2,T3> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2,
 @NonNull Validation<E,T3> validation3)

Combines three Validations into a Validation.Builder3.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

T3 - type of third valid value

Parameters:

validation1 - first validation

validation2 - second validation

validation3 - third validation

Returns:

an instance of Builder3<E,T1,T2,T3>

Throws:

NullPointerException - if validation1, validation2 or validation3 is null

combine

static <E,T1,T2,T3,T4>
Validation.Builder4<E,T1,T2,T3,T4> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2,
 @NonNull Validation<E,T3> validation3,
 @NonNull Validation<E,T4> validation4)

Combines four Validations into a Validation.Builder4.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

T3 - type of third valid value

T4 - type of fourth valid value

Parameters:

validation1 - first validation

validation2 - second validation

validation3 - third validation

validation4 - fourth validation

Returns:

an instance of Builder3<E,T1,T2,T3,T4>

Throws:

NullPointerException - if validation1, validation2, validation3 or validation4 is null

combine

static <E,T1,T2,T3,T4,T5>
Validation.Builder5<E,T1,T2,T3,T4,T5> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2,
 @NonNull Validation<E,T3> validation3,
 @NonNull Validation<E,T4> validation4,
 @NonNull Validation<E,T5> validation5)

Combines five Validations into a Validation.Builder5.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

T3 - type of third valid value

T4 - type of fourth valid value

T5 - type of fifth valid value

Parameters:

validation1 - first validation

validation2 - second validation

validation3 - third validation

validation4 - fourth validation

validation5 - fifth validation

Returns:

an instance of Builder3<E,T1,T2,T3,T4,T5>

Throws:

NullPointerException - if validation1, validation2, validation3, validation4 or validation5 is null

combine

static <E,T1,T2,T3,T4,T5,T6>
Validation.Builder6<E,T1,T2,T3,T4,T5,T6> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2,
 @NonNull Validation<E,T3> validation3,
 @NonNull Validation<E,T4> validation4,
 @NonNull Validation<E,T5> validation5,
 @NonNull Validation<E,T6> validation6)

Combines six Validations into a Validation.Builder6.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

T3 - type of third valid value

T4 - type of fourth valid value

T5 - type of fifth valid value

T6 - type of sixth valid value

Parameters:

validation1 - first validation

validation2 - second validation

validation3 - third validation

validation4 - fourth validation

validation5 - fifth validation

validation6 - sixth validation

Returns:

an instance of Builder3<E,T1,T2,T3,T4,T5,T6>

Throws:

NullPointerException - if validation1, validation2, validation3, validation4, validation5 or validation6 is null

combine

static <E,T1,T2,T3,T4,T5,T6,T7>
Validation.Builder7<E,T1,T2,T3,T4,T5,T6,T7> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2,
 @NonNull Validation<E,T3> validation3,
 @NonNull Validation<E,T4> validation4,
 @NonNull Validation<E,T5> validation5,
 @NonNull Validation<E,T6> validation6,
 @NonNull Validation<E,T7> validation7)

Combines seven Validations into a Validation.Builder7.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

T3 - type of third valid value

T4 - type of fourth valid value

T5 - type of fifth valid value

T6 - type of sixth valid value

T7 - type of seventh valid value

Parameters:

validation1 - first validation

validation2 - second validation

validation3 - third validation

validation4 - fourth validation

validation5 - fifth validation

validation6 - sixth validation

validation7 - seventh validation

Returns:

an instance of Builder3<E,T1,T2,T3,T4,T5,T6,T7>

Throws:

NullPointerException - if validation1, validation2, validation3, validation4, validation5, validation6 or validation7 is null

combine

static <E,T1,T2,T3,T4,T5,T6,T7,T8>
Validation.Builder8<E,T1,T2,T3,T4,T5,T6,T7,T8> combine(@NonNull Validation<E,T1> validation1,
 @NonNull Validation<E,T2> validation2,
 @NonNull Validation<E,T3> validation3,
 @NonNull Validation<E,T4> validation4,
 @NonNull Validation<E,T5> validation5,
 @NonNull Validation<E,T6> validation6,
 @NonNull Validation<E,T7> validation7,
 @NonNull Validation<E,T8> validation8)

Combines eight Validations into a Validation.Builder8.

Type Parameters:

E - type of error

T1 - type of first valid value

T2 - type of second valid value

T3 - type of third valid value

T4 - type of fourth valid value

T5 - type of fifth valid value

T6 - type of sixth valid value

T7 - type of seventh valid value

T8 - type of eighth valid value

Parameters:

validation1 - first validation

validation2 - second validation

validation3 - third validation

validation4 - fourth validation

validation5 - fifth validation

validation6 - sixth validation

validation7 - seventh validation

validation8 - eighth validation

Returns:

an instance of Builder3<E,T1,T2,T3,T4,T5,T6,T7,T8>

Throws:

NullPointerException - if validation1, validation2, validation3, validation4, validation5, validation6, validation7 or validation8 is null

isValid

boolean isValid()

Check whether this is of type Valid

Returns:

true if is a Valid, false if is an Invalid

isInvalid

boolean isInvalid()

Check whether this is of type Invalid

Returns:

true if is an Invalid, false if is a Valid

orElse

default Validation<E,T> orElse(@NonNull Validation<? extends E, ? extends T> other)

Returns this Validation if it is valid, otherwise return the alternative.

Parameters:

other - An alternative Validation

Returns:

this Validation if it is valid, otherwise return the alternative.

orElse

default Validation<E,T> orElse(@NonNull Supplier<Validation<? extends E, ? extends T>> supplier)

Returns this Validation if it is valid, otherwise return the result of evaluating supplier.

Parameters:

supplier - An alternative Validation supplier

Returns:

this Validation if it is valid, otherwise return the result of evaluating supplier.

isEmpty

default boolean isEmpty()

Description copied from interface: Value

Checks, this Value is empty, i.e. if the underlying value is absent.

Specified by:

isEmpty in interface Value<E>

Returns:

false, if no underlying value is present, true otherwise.

get

T get()

Gets the value of this Validation if is a Valid or throws if this is an Invalid.

Specified by:

get in interface Value<E>

Returns:

The value of this Validation

Throws:

NoSuchElementException - if this is an Invalid

getOrElseGet

default T getOrElseGet(@NonNull Function<? super E, ? extends T> other)

Gets the value if it is a Valid or an value calculated from the error.

Parameters:

other - a function which converts an error to an alternative value

Returns:

the value, if the underlying Validation is a Valid, or else the alternative value provided by other by applying the error.

getError

E getError()

Gets the error of this Validation if it is an Invalid or throws if this is a Valid.

Returns:

The error, if present

Throws:

RuntimeException - if this is a Valid

toEither

default Either<E,T> toEither()

Converts this Validation to an Either.

Returns:

Either.right(get()) if this is valid, otherwise Either.left(getError()).

equals

boolean equals(Object o)

Description copied from interface: Value

Clarifies that values have a proper equals() method implemented.

See Object.equals(Object).

Specified by:

equals in interface Value<E>

Overrides:

equals in class Object

Parameters:

o - An object

Returns:

true, if this equals o, false otherwise

hashCode

int hashCode()

Description copied from interface: Value

Clarifies that values have a proper hashCode() method implemented.

See Object.hashCode().

Specified by:

hashCode in interface Value<E>

Overrides:

hashCode in class Object

Returns:

The hashcode of this object

toString

String toString()

Description copied from interface: Value

Clarifies that values have a proper toString() method implemented.

See Object.toString().

Specified by:

toString in interface Value<E>

Overrides:

toString in class Object

Returns:

A String representation of this object

forEach

default void forEach(@NonNull Consumer<? super T> action)

Performs the given action for the value contained in Valid, or does nothing if this is an Invalid.

Specified by:

forEach in interface Iterable<E>

Specified by:

forEach in interface Value<E>

Parameters:

action - the action to be performed on the contained value

Throws:

NullPointerException - if action is null

fold

default <U> U fold(@NonNull Function<? super E, ? extends U> ifInvalid,
 @NonNull Function<? super T, ? extends U> ifValid)

Transforms this Validation to a value of type U.

Example:

Validation<List<String>, String> valid = ...;<br>
int i = valid.fold(List::length, String::length);

Type Parameters:

U - the fold result type

Parameters:

ifInvalid - an error mapper

ifValid - an mapper for a valid value

Returns:

ifValid.apply(get()) if this is valid, otherwise ifInvalid.apply(getError()).

Throws:

NullPointerException - if one of the given mappers ifInvalid or ifValid is null

swap

default Validation<T,E> swap()

Flip the valid/invalid values for this Validation. If this is a Valid<E,T>, returns Invalid<T,E>. Or if this is an Invalid<E,T>, return a Valid<T,E>.

Returns:

a flipped instance of Validation

map

default <U> Validation<E,U> map(@NonNull Function<? super T, ? extends U> f)

Description copied from interface: Value

Maps the underlying value to a different component type.

Specified by:

map in interface Value<E>

Type Parameters:

U - The new component type

Parameters:

f - A mapper

Returns:

A new value

bimap

default <E2,T2> Validation<E2,T2> bimap(@NonNull Function<? super E, ? extends E2> errorMapper,
 @NonNull Function<? super T, ? extends T2> valueMapper)

Whereas map only performs a mapping on a valid Validation, and mapError performs a mapping on an invalid Validation, bimap allows you to provide mapping actions for both, and will give you the result based on what type of Validation this is. Without this, you would have to do something like: validation.map(...).mapError(...);

Type Parameters:

E2 - type of the mapping result if this is an invalid

T2 - type of the mapping result if this is a valid

Parameters:

errorMapper - the invalid mapping operation

valueMapper - the valid mapping operation

Returns:

an instance of Validation<U,R>

Throws:

NullPointerException - if invalidMapper or validMapper is null

mapError

default <U> Validation<U,T> mapError(@NonNull Function<? super E, ? extends U> f)

Applies a function f to the error of this Validation if this is an Invalid. Otherwise does nothing if this is a Valid.

Type Parameters:

U - type of the error resulting from the mapping

Parameters:

f - a function that maps the error in this Invalid

Returns:

an instance of Validation<U,T>

Throws:

NullPointerException - if mapping operation f is null

ap

default <U> Validation<Seq<E>,U> ap(@NonNull Validation<Seq<E>, ? extends Function<? super T, ? extends U>> validation)

Applies a validation containing a function to this validation's value, combining errors if both are invalid. This is the applicative functor's ap operation for Validation.

Type Parameters:

U - type of the result of applying the function

Parameters:

validation - the validation containing the function to apply

Returns:

a valid Validation with the result if both are valid, otherwise an invalid Validation with accumulated errors

Throws:

NullPointerException - if validation is null

combine

default <U> Validation.Builder<E,T,U> combine(Validation<E,U> validation)

Combines two Validations to form a Validation.Builder, which can then be used to perform further combines, or apply a function to it in order to transform the Validation.Builder into a Validation.

Type Parameters:

U - type of the value contained in validation

Parameters:

validation - the validation object to combine this with

Returns:

an instance of Builder

filter

default Option<Validation<E,T>> filter(@NonNull Predicate<? super T> predicate)

Filters this Validation by testing a predicate on the value. If this is an Invalid or if the predicate matches, returns Some of this Validation, otherwise returns None.

Parameters:

predicate - A predicate to test the value

Returns:

Some(this) if this is an Invalid or the predicate matches, otherwise None

Throws:

NullPointerException - if predicate is null

flatMap

default <U> Validation<E,U> flatMap(@NonNull Function<? super T, ? extends Validation<E, ? extends U>> mapper)

FlatMaps the value of this Validation if it is valid, otherwise returns this Invalid.

Type Parameters:

U - type of the returned Validation value

Parameters:

mapper - the mapper function to apply to the value

Returns:

a new Validation

Throws:

NullPointerException - if mapper is null

peek

default Validation<E,T> peek(@NonNull Consumer<? super T> action)

Description copied from interface: Value

Performs the given action on the first element if this is an eager implementation. Performs the given action on all elements (the first immediately, successive deferred), if this is a lazy implementation.

Specified by:

peek in interface Value<E>

Parameters:

action - The action that will be performed on the element(s).

Returns:

this instance

isAsync

default boolean isAsync()

A Validation's value is computed synchronously.

Specified by:

isAsync in interface Value<E>

Returns:

false

isLazy

default boolean isLazy()

A Validation's value is computed eagerly.

Specified by:

isLazy in interface Value<E>

Returns:

false

isSingleValued

default boolean isSingleValued()

Description copied from interface: Value

States whether this is a single-valued type.

Specified by:

isSingleValued in interface Value<E>

Returns:

true if this is single-valued, false otherwise.

iterator

default @NonNull Iterator<T> iterator()

Description copied from interface: Value

Returns a rich io.vavr.collection.Iterator.

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Value<E>

Returns:

A new Iterator