Refactored use case to improve readability (android10#37)

Replace execute function by invoke operator Moved onResult function as a last parameter Fixed all test

Author: carbaj03

app/src/main/kotlin/com/fernandocejas/sample/core/interactor/UseCase.kt

@@ -34,9 +34,9 @@ abstract class UseCase<out Type, in Params> where Type : Any {
 
  abstract suspend fun run(params: Params): Either<Failure, Type>
 
- fun execute(onResult: (Either<Failure, Type>) -> Unit, params: Params) {
+ operator fun invoke(params: Params, onResult: (Either<Failure, Type>) -> Unit = {}) {
  val job = async(CommonPool) { run(params) }
- launch(UI) { onResult.invoke(job.await()) }
+ launch(UI) { onResult(job.await()) }
  }
 
  class None

app/src/main/kotlin/com/fernandocejas/sample/features/movies/MovieDetailsViewModel.kt

@@ -26,11 +26,11 @@ class MovieDetailsViewModel
 
  var movieDetails: MutableLiveData<MovieDetailsView> = MutableLiveData()
 
- fun loadMovieDetails(movieId: Int) {
- getMovieDetails.execute({ it.either(::handleFailure, ::handleMovieDetails) }, Params(movieId))
- }
+ fun loadMovieDetails(movieId: Int) =
+ getMovieDetails(Params(movieId)) { it.either(::handleFailure, ::handleMovieDetails) }
 
- fun playMovie(url: String) = playMovie.execute({}, PlayMovie.Params(url))
+ fun playMovie(url: String) =
+ playMovie(PlayMovie.Params(url))
 
  private fun handleMovieDetails(movie: MovieDetails) {
  this.movieDetails.value = MovieDetailsView(movie.id, movie.title, movie.poster,

app/src/main/kotlin/com/fernandocejas/sample/features/movies/MoviesViewModel.kt

@@ -25,7 +25,7 @@ class MoviesViewModel
 
  var movies: MutableLiveData<List<MovieView>> = MutableLiveData()
 
- fun loadMovies() = getMovies.execute({ it.either(::handleFailure, ::handleMovieList) }, None())
+ fun loadMovies() = getMovies(None()) { it.either(::handleFailure, ::handleMovieList) }
 
  private fun handleMovieList(movies: List<Movie>) {
  this.movies.value = movies.map { MovieView(it.id, it.poster) }

app/src/test/kotlin/com/fernandocejas/sample/core/interactor/UseCaseTest.kt

@@ -43,7 +43,7 @@ class UseCaseTest : AndroidTest() {
  val params = MyParams("TestParam")
  val onResult = { myResult: Either<Failure, MyType> -> result = myResult }
 
- runBlocking { useCase.execute(onResult, params) }
+ runBlocking { useCase(params, onResult) }
 
  result shouldEqual Right(MyType(TYPE_TEST))
  }

app/src/test/kotlin/com/fernandocejas/sample/features/movies/PlayMovieTest.kt

@@ -39,7 +39,7 @@ class PlayMovieTest : AndroidTest() {
  @Test fun `should play movie trailer`() {
  val params = PlayMovie.Params(VIDEO_URL)
 
- playMovie.execute({}, params)
+ playMovie(params)
 
  verify(navigator).openVideo(context, VIDEO_URL)
  }