Package e.java

Interface EOr<A>

Type Parameters:

A - Type of the value this EOr can contain

All Known Implementing Classes:

EOr.Failure, EOr.Success

public interface EOr<A>

A container that can either be a Failure containing an E or Success containing a value

See Also:

• E

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	EOr.Failure<A>	A failed EOr
static final class	EOr.Success<A>	A successful EOr

Field Summary

Fields

Modifier and Type	Field	Description
static final E	filteredError	A default E to be used when condition does not hold while filtering an EOr
static final EOr<Void>	unit	A successful EOr of type Unit

Method Summary

Modifier and Type	Method	Description
default <B> EOr<B>	andThen(Supplier<EOr<B>> next)	Provides a next EOr if this one has a value, ignoring the value
static <A> EOr<A>	catching(UnsafeSupplier<A> f, Function<Throwable,E> ifFailure)	Constructs an EOr from a computation that can throw
default Optional<E>	error()
default EOr<A>	filter(Function<A,Boolean> condition)	Filters this EOr by value in it, if it exists
default EOr<A>	filter(Function<A,Boolean> condition, Function<A,E> filteredError)	Filters this EOr by value in it, if it exists, using given function
default <B> EOr<B>	flatMap(Function<A,EOr<B>> f)	Computes a new EOr using value in this, if it exists, with given flat mapping function
default EOr<A>	flatMapError(Function<E,EOr<A>> f)	Computes a new EOr using E in this, if it exists, with given flat mapping function
default <B> B	fold(Function<E,B> ifFailure, Function<A,B> ifSuccess)	Folds this into a single value, handling both E and value conversions with given functions
default EOr<A>	forEach(Consumer<A> f)	Alias of `onValue`
static <A> EOr<A>	from(A a)	Constructs a successful EOr containing given value
static <A> EOr<A>	from(E e)	Constructs a failed EOr containing given E
static <A> EOr<A>	fromNullable(A a, Supplier<E> ifNull)	Constructs an EOr from a nullable value
static <A> EOr<A>	fromOptional(Optional<A> a, Supplier<E> ifEmpty)	Constructs an EOr from an Optional value
default A	getOrElse(Supplier<A> alternative)	Gets the value in this or falls back to given default value
default boolean	hasError()
default boolean	hasValue()
default <B> EOr<B>	map(Function<A,B> f)	Converts value in this, if it exists, using given mapping function to make a new EOr
default EOr<A>	mapError(Function<E,E> f)	Converts E in this, if it exists, using given mapping function to make a new EOr
default EOr<A>	onError(Consumer<E> f)	Performs a side-effect using error in this, if it exists
default EOr<A>	onValue(Consumer<A> f)	Performs a side-effect using value in this, if it exists
default EOr<A>	orElse(Supplier<EOr<A>> alternative)	Provides an alternative EOr if this one has E, ignoring the E
default Optional<A>	value()

Field Details

unit

static final EOr<Void> unit

A successful EOr of type Unit

filteredError

static final E filteredError

A default E to be used when condition does not hold while filtering an EOr

See Also:

• filter(java.util.function.Function<A, java.lang.Boolean>, java.util.function.Function<A, e.java.E>)

Method Details

hasError

default boolean hasError()

Returns:

Whether or not this contains an E

hasValue

default boolean hasValue()

Returns:

Whether or not this contains a value

error

default Optional<E> error()

Returns:

E in this as an Optional

value

default Optional<A> value()

Returns:

Value in this as an Optional

map

default <B> EOr<B> map(Function<A,B> f)

Converts value in this, if it exists, using given mapping function to make a new EOr

Type Parameters:

B - Type of the new value

Parameters:

f - Mapping function

Returns:

A new EOr containing either the new value or E in this one

flatMap

default <B> EOr<B> flatMap(Function<A,EOr<B>> f)

Computes a new EOr using value in this, if it exists, with given flat mapping function

Type Parameters:

B - Type of the new value

Parameters:

f - Flat mapping function

Returns:

Computed EOr or a new EOr containing E in this one

mapError

default EOr<A> mapError(Function<E,E> f)

Converts E in this, if it exists, using given mapping function to make a new EOr

Parameters:

f - E mapping function

Returns:

This EOr or a new EOr containing computed E if this one has E

flatMapError

default EOr<A> flatMapError(Function<E,EOr<A>> f)

Computes a new EOr using E in this, if it exists, with given flat mapping function

Parameters:

f - E flat mapping function

Returns:

This EOr or a computed EOr if this one has E

fold

default <B> B fold(Function<E,B> ifFailure,
 Function<A,B> ifSuccess)

Folds this into a single value, handling both E and value conversions with given functions

Type Parameters:

B - Type of the desired result

Parameters:

ifFailure - Conversion function for E

ifSuccess - Conversion function for value

Returns:

Converted result

getOrElse

default A getOrElse(Supplier<A> alternative)

Gets the value in this or falls back to given default value

Parameters:

alternative - Default value to use in case this has E

Returns:

Value in this or given default value

orElse

default EOr<A> orElse(Supplier<EOr<A>> alternative)

Provides an alternative EOr if this one has E, ignoring the E

Parameters:

alternative - Alternative EOr in case this one has E

Returns:

This EOr or alternative if this one has E

andThen

default <B> EOr<B> andThen(Supplier<EOr<B>> next)

Provides a next EOr if this one has a value, ignoring the value

Type Parameters:

B - Type of value in next EOr

Parameters:

next - Next EOr in case this one has a value

Returns:

Next EOr or a new EOr containing E in this one

onError

default EOr<A> onError(Consumer<E> f)

Performs a side-effect using error in this, if it exists

Parameters:

f - Side-effecting function

Returns:

This EOr for chaining

onValue

default EOr<A> onValue(Consumer<A> f)

Performs a side-effect using value in this, if it exists

Parameters:

f - Side-effecting function

Returns:

This EOr for chaining

forEach

default EOr<A> forEach(Consumer<A> f)

Alias of `onValue`

Returns:

This EOr for chaining

See Also:

• onValue(java.util.function.Consumer<A>)

filter

default EOr<A> filter(Function<A,Boolean> condition,
 Function<A,E> filteredError)

Filters this EOr by value in it, if it exists, using given function

Parameters:

condition - Filtering function

filteredError - E conversion function

Returns:

This EOr of a new EOr containing an E computed by given conversion function

filter

default EOr<A> filter(Function<A,Boolean> condition)

Filters this EOr by value in it, if it exists

Parameters:

condition - Filtering function

Returns:

This EOr of a new EOr containing an E

See Also:

• filteredError

from

static <A> EOr<A> from(E e)

Constructs a failed EOr containing given E

Type Parameters:

A - Type of value of resulting EOr

Parameters:

e - An E

Returns:

A new failed EOr containing given E

from

static <A> EOr<A> from(A a)

Constructs a successful EOr containing given value

Type Parameters:

A - Type of value of resulting EOr

Parameters:

a - A value

Returns:

A new failed EOr containing given value

fromNullable

static <A> EOr<A> fromNullable(A a,
 Supplier<E> ifNull)

Constructs an EOr from a nullable value

Type Parameters:

A - Type of value

Parameters:

a - A nullable value

ifNull - An error to use in case value is null

Returns:

An EOr containing either value or given E

fromOptional

static <A> EOr<A> fromOptional(Optional<A> a,
 Supplier<E> ifEmpty)

Constructs an EOr from an Optional value

Type Parameters:

A - Type of value

Parameters:

a - An Optional value

ifEmpty - An error to use in case value is empty

Returns:

An EOr containing either value or given E

catching

static <A> EOr<A> catching(UnsafeSupplier<A> f,
 Function<Throwable,E> ifFailure)

Constructs an EOr from a computation that can throw

Type Parameters:

A - Type of value

Parameters:

f - A computation that can throw

ifFailure - An E conversion function

Returns:

An EOr containing either computed value or an E computed by given function