KState-Saga/ca.acendas.kstate.saga/StepOutcome

StepOutcome

sealed interface StepOutcome<out R>

Represents the outcome of a saga step execution.

This sealed interface provides type-safe, explicit control flow for saga steps, replacing exception-based cancellation with clean architecture principles.

Outcome Types

Completed - Step completed successfully with a result value
Failed - Step failed, triggering compensation for completed steps
Skipped - Step skipped, returning last successful result without compensation

Usage Example

enum class OrderSteps { VALIDATE, PAYMENT, SHIP }
enum class FailureReason { INVALID_ORDER, PAYMENT_DECLINED }
enum class SkipReason { ALREADY_PROCESSED }

first call OrderSteps.VALIDATE with { ctx ->
    if (!ctx.valid) fails with FailureReason.INVALID_ORDER
    if (ctx.alreadyProcessed) skip with SkipReason.ALREADY_PROCESSED

    val order = validateOrder(ctx)
    completes with order
}

Parameters

The result type on successful completion

Inheritors

Completed

Failed

Skipped

Types

Completed

data class Completed<R>(val value: R) : StepOutcome<R>

Step completed successfully with result.

Failed

data class Failed(val failureReason: TypedValue) : StepOutcome<Nothing>

Step failed with a reason.

Skipped

data class Skipped(val skipReason: TypedValue) : StepOutcome<Nothing>

Step skipped with a reason.