/
SagaManager.kt
84 lines (77 loc) · 3.18 KB
/
SagaManager.kt
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/*
* Copyright (c) 2023 Fraktalio D.O.O. All rights reserved.
*
* 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.
*/
package com.fraktalio.fmodel.application
import com.fraktalio.fmodel.domain.ISaga
import kotlinx.coroutines.flow.Flow
/**
* Saga manager - Stateless process orchestrator.
* It is reacting on Action Results of type [AR] and produces new actions [A] based on them.
*
* [SagaManager] extends [ISaga] and [ActionPublisher] interfaces,
* clearly communicating that it is composed out of these two behaviours.
*
* @author Иван Дугалић / Ivan Dugalic / @idugalic
*/
interface SagaManager<AR, A> : ISaga<AR, A>, ActionPublisher<A> {
/**
* Computes new Actions based on the Action Results.
*
* @return The newly computed [Flow] of Actions/[A]
*/
fun AR.computeNewActions(): Flow<A> = react(this)
}
/**
* Saga Manager factory function.
*
* The Delegation pattern has proven to be a good alternative to implementation inheritance, and Kotlin supports it natively requiring zero boilerplate code.
*
* @param AR Action Result of type [AR], Action Result is usually an Event
* @param A An Action of type [A] to be taken. Action is usually a Command.
* @property saga A saga component of type [ISaga]<[AR], [A]>
* @property actionPublisher Interface for publishing the Actions of type [A] - dependencies by delegation
* @return An object/instance of type [SagaManager]<[AR], [A]>
*
* @author Иван Дугалић / Ivan Dugalic / @idugalic
*/
@Deprecated(
message = "Use SagaManager constructor-like function instead",
replaceWith = ReplaceWith("SagaManager(saga, actionPublisher)")
)
fun <AR, A> sagaManager(
saga: ISaga<AR, A>,
actionPublisher: ActionPublisher<A>
): SagaManager<AR, A> = object : SagaManager<AR, A>,
ActionPublisher<A> by actionPublisher,
ISaga<AR, A> by saga {}
/**
* Saga Manager constructor-like function.
*
* The Delegation pattern has proven to be a good alternative to implementation inheritance, and Kotlin supports it natively requiring zero boilerplate code.
*
* @param AR Action Result of type [AR], Action Result is usually an Event
* @param A An Action of type [A] to be taken. Action is usually a Command.
* @property saga A saga component of type [ISaga]<[AR], [A]>
* @property actionPublisher Interface for publishing the Actions of type [A] - dependencies by delegation
* @return An object/instance of type [SagaManager]<[AR], [A]>
*
* @author Иван Дугалић / Ivan Dugalic / @idugalic
*/
fun <AR, A> SagaManager(
saga: ISaga<AR, A>,
actionPublisher: ActionPublisher<A>
): SagaManager<AR, A> = object : SagaManager<AR, A>,
ActionPublisher<A> by actionPublisher,
ISaga<AR, A> by saga {}