Lightweight abstractions for clean-architecture flows: explicit Result success/failure type, synchronous and suspending use-case interfaces, presentation logic handler, and flattened Cause for safe error passing.
Kotlin Multiplatform architecture library providing lightweight abstractions for clean architecture: Result, IUseCase, ISuspendingUseCase, ILogicHandler, and Cause.
Add dependency to build.gradle.kts:
repositories {
mavenCentral()
}
kotlin {
sourceSets {
commonMain.dependencies {
implementation("cz.sazel.arch:arch-patterns:0.1.0")
}
}
}Explicit result type representing success (Ok) or failure (Fail) without throwing runtime exceptions.
Result.Ok(data): Holds success value OK.Result.Fail(reason): Holds failure reason FAIL.UnitResult<FAIL>: Typealias for Result<Unit, FAIL>.mapOk, mapFail, map
onOk, onFail (flat-map style for suspending and non-suspending operations)fold(onSuccess, onFailure)
Result.catching(call, onError)
dataOrThrow, dataOrNull, failReasonOrNull
Abstractions for single domain operations in Clean Architecture.
IUseCase<INPUT, OUTPUT, FAIL>: Synchronous use case returning Result<OUTPUT, FAIL>.ISuspendingUseCase<INPUT, OUTPUT, FAIL>: Suspending use case returning Result<OUTPUT, FAIL>.Unit as INPUT when no input parameter is needed.Use cases typically define a sealed interface Fail for typed domain errors.
Presentation layer interface for single-step operations. Calls use cases and handles presentation output or error formatting.
Flattened exception data structure (type, message, stackTrace) safe for passing across module and layer boundaries. Use Cause.of(throwable) to flatten any Throwable.
class RenameDeviceUC(
private val store: PreferencesStore,
) : ISuspendingUseCase<DeviceName, DeviceName, RenameDeviceUC.Fail> {
sealed interface Fail {
data class Rejected(val fault: String) : Fail
data class Unwritable(val cause: Cause?) : Fail
}
override suspend fun invoke(input: DeviceName): Result<DeviceName, Fail> =
if (input.value.isBlank()) {
Result.Fail(Fail.Rejected("Name cannot be empty"))
} else {
store.saveName(input)
.mapFail { Fail.Unwritable(it.cause) }
.mapOk { input }
}
}class RegisterUserUC(
private val validateEmail: EmailValidatorUC,
private val saveUser: SaveUserUC,
) : ISuspendingUseCase<Email, User, RegisterUserUC.Fail> {
sealed interface Fail {
data object InvalidEmail : Fail
data class StorageError(val cause: Cause?) : Fail
}
override suspend fun invoke(input: Email): Result<User, Fail> =
validateEmail(input)
.mapFail { Fail.InvalidEmail }
.onOk { validEmail ->
saveUser(validEmail).mapFail { Fail.StorageError(it.cause) }
}
}class GetConfigLogicHandler(
private val terminal: Terminal,
private val deviceNameSetting: DeviceNameSettingUC,
) : ILogicHandler<ConfigKey> {
override suspend fun invoke(input: ConfigKey) = when (input) {
ConfigKey.DEVICE_NAME -> deviceNameSetting(Unit).fold(
onSuccess = { setting -> terminal.println(setting.configuredName) },
onFailure = { error -> terminal.warning("Error loading config: $error") },
)
}
}suspend fun fetchDataFromNetwork(): Result<String, Cause> =
Result.catching(
call = { httpClient.get("https://api.example.com/data") },
onError = { Cause.of(it) }
)Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Kotlin Multiplatform architecture library providing lightweight abstractions for clean architecture: Result, IUseCase, ISuspendingUseCase, ILogicHandler, and Cause.
Add dependency to build.gradle.kts:
repositories {
mavenCentral()
}
kotlin {
sourceSets {
commonMain.dependencies {
implementation("cz.sazel.arch:arch-patterns:0.1.0")
}
}
}Explicit result type representing success (Ok) or failure (Fail) without throwing runtime exceptions.
Result.Ok(data): Holds success value OK.Result.Fail(reason): Holds failure reason FAIL.UnitResult<FAIL>: Typealias for Result<Unit, FAIL>.mapOk, mapFail, map
onOk, onFail (flat-map style for suspending and non-suspending operations)fold(onSuccess, onFailure)
Result.catching(call, onError)
dataOrThrow, dataOrNull, failReasonOrNull
Abstractions for single domain operations in Clean Architecture.
IUseCase<INPUT, OUTPUT, FAIL>: Synchronous use case returning Result<OUTPUT, FAIL>.ISuspendingUseCase<INPUT, OUTPUT, FAIL>: Suspending use case returning Result<OUTPUT, FAIL>.Unit as INPUT when no input parameter is needed.Use cases typically define a sealed interface Fail for typed domain errors.
Presentation layer interface for single-step operations. Calls use cases and handles presentation output or error formatting.
Flattened exception data structure (type, message, stackTrace) safe for passing across module and layer boundaries. Use Cause.of(throwable) to flatten any Throwable.
class RenameDeviceUC(
private val store: PreferencesStore,
) : ISuspendingUseCase<DeviceName, DeviceName, RenameDeviceUC.Fail> {
sealed interface Fail {
data class Rejected(val fault: String) : Fail
data class Unwritable(val cause: Cause?) : Fail
}
override suspend fun invoke(input: DeviceName): Result<DeviceName, Fail> =
if (input.value.isBlank()) {
Result.Fail(Fail.Rejected("Name cannot be empty"))
} else {
store.saveName(input)
.mapFail { Fail.Unwritable(it.cause) }
.mapOk { input }
}
}class RegisterUserUC(
private val validateEmail: EmailValidatorUC,
private val saveUser: SaveUserUC,
) : ISuspendingUseCase<Email, User, RegisterUserUC.Fail> {
sealed interface Fail {
data object InvalidEmail : Fail
data class StorageError(val cause: Cause?) : Fail
}
override suspend fun invoke(input: Email): Result<User, Fail> =
validateEmail(input)
.mapFail { Fail.InvalidEmail }
.onOk { validEmail ->
saveUser(validEmail).mapFail { Fail.StorageError(it.cause) }
}
}class GetConfigLogicHandler(
private val terminal: Terminal,
private val deviceNameSetting: DeviceNameSettingUC,
) : ILogicHandler<ConfigKey> {
override suspend fun invoke(input: ConfigKey) = when (input) {
ConfigKey.DEVICE_NAME -> deviceNameSetting(Unit).fold(
onSuccess = { setting -> terminal.println(setting.configuredName) },
onFailure = { error -> terminal.warning("Error loading config: $error") },
)
}
}suspend fun fetchDataFromNetwork(): Result<String, Cause> =
Result.catching(
call = { httpClient.get("https://api.example.com/data") },
onError = { Cause.of(it) }
)Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.