commonTest.com.fraktalio.fmodel.domain.examples.numbers.NumberSaga.kt Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of application-arrow Show documentation

Fmodel provides just enough tactical Domain-Driven Design patterns, optimised for Event Sourcing and CQRS. The application library orchestrates the execution of the logic by loading state, executing domain components and storing new state. It is an Arrow (FP library for Kotlin) flavored implementation.

There is a newer version: 3.6.0

Show newest version

/*
 * Copyright (c) 2021 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.domain.examples.numbers

import com.fraktalio.fmodel.domain.Saga
import com.fraktalio.fmodel.domain.examples.numbers.api.Description
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberCommand
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberCommand.EvenNumberCommand.AddEvenNumber
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberCommand.EvenNumberCommand.SubtractEvenNumber
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberCommand.OddNumberCommand.AddOddNumber
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberCommand.OddNumberCommand.SubtractOddNumber
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberEvent
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberEvent.EvenNumberEvent.EvenNumberAdded
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberEvent.EvenNumberEvent.EvenNumberSubtracted
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberEvent.OddNumberEvent.OddNumberAdded
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberEvent.OddNumberEvent.OddNumberSubtracted
import com.fraktalio.fmodel.domain.examples.numbers.api.NumberValue
import kotlinx.coroutines.flow.emptyFlow
import kotlinx.coroutines.flow.flowOf

/**
 * Very simple Number saga, just for fun ;)
 *
 * It reacts on Action Results of type of any Event (Even or Odd) and issue a Command/Action (Odd or Even)
 * For example if the EvenNumberAdded happened with value 4, a new command of type AddOddNumber will be published with value EvenNumberAdded-1=3
 *
 * @return number Saga instance
 */
fun numberSaga() = Saga(
    react = { numberEvent ->
        when (numberEvent) {
            is EvenNumberAdded -> flowOf(
                AddOddNumber(
                    Description("${numberEvent.value.get - 1}"),
                    NumberValue(numberEvent.value.get - 1)
                )
            )
            is EvenNumberSubtracted -> flowOf(
                SubtractOddNumber(
                    Description("${numberEvent.value.get - 1}"),
                    NumberValue(numberEvent.value.get - 1)
                )
            )
            is OddNumberAdded -> flowOf(
                AddEvenNumber(
                    Description("${numberEvent.value.get + 1}"),
                    NumberValue(numberEvent.value.get + 1)
                )
            )
            is OddNumberSubtracted -> flowOf(
                SubtractEvenNumber(
                    Description("${numberEvent.value.get + 1}"),
                    NumberValue(numberEvent.value.get + 1)
                )
            )
            else -> emptyFlow()
        }
    }
)

/**
 * Even number saga - not doing much
 *
 * It reacts on Action Results of type of any [NumberEvent.EvenNumberEvent] and issue a Command/Action of type [NumberCommand.OddNumberCommand]
 *
 * @return even number Saga instance
 */
fun evenNumberSaga() = Saga(
    react = { numberEvent -> emptyFlow() }
)

/**
 * Odd number saga
 *
 * It reacts on Action Results of type of any [NumberEvent.OddNumberEvent] and issue a Command/Action of type [NumberCommand.EvenNumberCommand]
 *
 * @return odd number Saga instance
 */
fun oddNumberSaga() = Saga(
    react = { numberEvent ->
        when (numberEvent) {
            is OddNumberAdded -> flowOf(
                AddEvenNumber(
                    Description("${numberEvent.value.get + 1}"),
                    NumberValue(numberEvent.value.get + 1)
                )
            )
            is OddNumberSubtracted -> flowOf(
                SubtractEvenNumber(
                    Description("${numberEvent.value.get + 1}"),
                    NumberValue(numberEvent.value.get + 1)
                )
            )
            else -> emptyFlow()
        }
    }
)