Actions dispatcher

Example

To enable generation, annotate action class with @ActionElement annotation:

class State

@ActionElement(state = State::class)
sealed class Action

object OpenArticleDetail : Action()
object LikeArticle : Action()
object DislikeArticle : Action()
object AddArticleToFavorite : Action()

After doing that you will get an auto-generated ActionReceiver interface:

interface ActionReceiver {
    fun processAddArticleToFavorite(
        previousState: State, 
        action: AddArticleToFavorite
    ): Pair<State, Function0<Action?>?>
    
    fun processDislikeArticle(
        previousState: State, 
        action: DislikeArticle
    ): Pair<State, Function0<Action?>?>
    
    fun processLikeArticle(
        previousState: State, 
        action: LikeArticle
    ): Pair<State, Function0<Action?>?>
    
    fun processOpenArticleDetail(
        previousState: State, 
        action: OpenArticleDetail
    ): Pair<State, Function0<Action?>?>
}

And ActionsReducer with reduce function:

class ActionsReducer private constructor(private val receiver: ActionReceiver) {
    fun reduce(previousState: State, action: Action): Pair<State, Function0<Action?>?> = when (action) {
        is DislikeArticle -> receiver.processDislikeArticle(previousState, action)
        is OpenArticleDetail -> receiver.processOpenArticleDetail(previousState, action)
        is AddArticleToFavorite -> receiver.processAddArticleToFavorite(previousState, action)
        is LikeArticle -> receiver.processLikeArticle(previousState, action)
    }
}

All you have to do after adding an annotation is to use a generated builder which will create this reducer for you and also you will need to implement a receiver:

class MyPresenter : BasePresenter<State, View, Action>(), ActionReceiver {
    private val reducer = ActionsReducer.Builder()
        .receiver(this) // <-- a class wich implements ActionReceiver and will receive reduce calls
        .build()

    fun reduce(previusState: State, action: Action) {
        reducer.reduce(previusState, action)
    }

    override fun processAddArticleToFavorite(previousState: State, action: Action): Pair<State, Function0<Action?>?> {
        // process add article to favorite
    }

    override fun processDislikeArticle(previousState: State, action: Action): Pair<State, Function0<Action?>?> {
        // process dislike article
    }

    override fun processLikeArticle(previousState: State, action: Action): Pair<State, Function0<Action?>?> {
         // process like article
    }

    override fun processOpenArticleDetail(previousState: State, action: Action): Pair<State, Function0<Action?>?> {
         // process open details article
    }
}

Download

Add a Gradle dependency:

apply plugin: 'kotlin-kapt'

sourceSets {
    main.java.srcDirs += 'src/main/kotlin'
    main.java.srcDirs += 'build/generated/source/kaptKotlin/main'           // <-- add to your module
    debug.java.srcDirs += 'build/generated/source/kaptKotlin/debug'         // <-- add to your module
    release.java.srcDirs += 'build/generated/source/kaptKotlin/release'     // <-- add to your module
    test.java.srcDirs += 'src/test/kotlin'
}

implementation 'com.github.rougsig:actions-dispatcher-runtime:2.0.0'
kapt 'com.github.rougsig:actions-dispatcher-processor:2.0.0'