3.1.1

State/opensavvy.state.outcome/Outcome

Outcome

sealed class Outcome<out Failure, out Value>(source)

The result of an operation.

To store progress information as well as the result of the operation, please see ProgressiveOutcome.

There are two possible cases:

Success if a successful result is available (see Success.value),
Failure if a failed result is available (see Failure.failure).

To create outcomes from computations, use the successful and failed factories.

Arrow

Outcome is essentially identical to Arrow's Either. When using Arrow, we recommend using Either most of the time because of all the convenience functions and DSLs it has. Using our companion library state-arrow, it is possible to use Outcome in the Raise DSL.

Because of this, we will keep Outcome as simple as possible, and avoid adding too much sugar.

Inheritors

Types

data class Failure<Failure>(val failure: Failure) : Outcome<Failure, Nothing>

The latest known result of the operation was a failure, available as failure.

data class Success<Value>(val value: Value) : Outcome<Nothing, Value>

The latest known result of the operation was a success, available as value.

Properties

val <Failure> Outcome<Failure, Nothing>.failure: Failure

Returns Failure.failure.

val <Failure : Any> Outcome<Failure, *>.failureOrNull: Failure?

Returns Failure.failure, or null if this outcome is not a failure.

val <Value> Outcome<Nothing, Value>.value: Value

Returns Success.value.

val <Value : Any> Outcome<*, Value>.valueOrNull: Value?

Returns Success.value, or null if this outcome is not successful.

Functions

inline fun <Failure, InputValue, OutputValue> Outcome<Failure, InputValue>.map(transform: (InputValue) -> OutputValue): Outcome<Failure, OutputValue>

If this outcome is successful, replaces its value using transform.

inline fun <InputFailure, Value, OutputFailure> Outcome<InputFailure, Value>.mapFailure(transformFailure: (InputFailure) -> OutputFailure): Outcome<OutputFailure, Value>

If this outcome is failed, replaces its failure using transformFailure.

inline fun <Failure> Outcome<Failure, *>.onFailure(block: (Failure) -> Unit)

Executes block if this outcome is a failure.

inline fun <Value> Outcome<*, Value>.onSuccess(block: (Value) -> Unit)

Executes block if this outcome is successful.

fun <Failure, Value> Outcome<Failure, Value>.toEither(): Either<Failure, Value>

Converts an Outcome into a typed Either.

fun <Failure, Value> Outcome<Failure, Value>.withProgress(progress: Progress = done()): ProgressiveOutcome<Failure, Value>

Adds progress information to this outcome to make it a ProgressiveOutcome.