ref: introduce feature abstraction/contract

Author: android10

app/src/main/kotlin/com/fernandocejas/sample/AndroidApplication.kt

@@ -16,7 +16,8 @@
 package com.fernandocejas.sample
 
 import android.app.Application
-import com.fernandocejas.sample.core.di.appModule
+import com.fernandocejas.sample.core.allFeatures
+import com.fernandocejas.sample.core.di.coreModule
 import org.koin.android.ext.koin.androidContext
 import org.koin.android.ext.koin.androidLogger
 import org.koin.core.context.GlobalContext.startKoin
@@ -34,7 +35,7 @@ class AndroidApplication : Application() {
         startKoin {
             androidContext(this@AndroidApplication)
             androidLogger()
-            modules(appModule)
+            modules(allFeatures().map { it.diModule() })
         }
     }
 }

app/src/main/kotlin/com/fernandocejas/sample/core/Core.kt

@@ -0,0 +1,57 @@
+package com.fernandocejas.sample.core
+
+import com.fernandocejas.sample.core.di.coreModule
+import com.fernandocejas.sample.features.login.loginFeature
+import com.fernandocejas.sample.features.movies.moviesFeature
+import org.koin.core.module.Module
+
+/**
+ * The fundamental piece of modularity.
+ *
+ * An Application always contains features,
+ * and that is represented by this
+ * contract/abstraction.
+ */
+interface Feature {
+
+    /**
+     * Convention: The feature name should follow
+     * the package name where the feature is contained
+     * using lower case.
+     *
+     * Examples:
+     *  - core
+     *  - login
+     *  - movies
+     */
+    fun name(): String
+
+    /**
+     * Koin DI Module that will be included
+     * when creating the Dependency Graph
+     * at Application Startup.
+     *
+     * In case of scoping this will facilitate
+     * refactor.
+     */
+    fun diModule(): Module
+
+    /**
+     * LEARNING PURPOSE:
+     * In order to keep modularity, each feature could
+     * point to the tables in the database related
+     * to the feature itself.
+     */
+    // fun databaseTables(): List<Table> = emptyList()
+}
+
+private fun coreFeature() = object : Feature {
+    override fun name() = "core"
+    override fun diModule() = coreModule
+}
+
+fun allFeatures() = listOf(
+    coreFeature(),
+    loginFeature(),
+    moviesFeature(),
+)

app/src/main/kotlin/com/fernandocejas/sample/core/di/AppModule.kt

@@ -0,0 +1,23 @@
+package com.fernandocejas.sample.core.di
+
+import com.fernandocejas.sample.core.navigation.Navigator
+import com.fernandocejas.sample.core.platform.NetworkHandler
+import okhttp3.OkHttpClient
+import org.koin.core.module.dsl.singleOf
+import org.koin.dsl.module
+import retrofit2.Retrofit
+import retrofit2.converter.gson.GsonConverterFactory
+
+val coreModule = module {
+    singleOf(::retrofit)
+    singleOf(::NetworkHandler)
+    singleOf(::Navigator)
+}
+
+private fun retrofit(): Retrofit {
+    return Retrofit.Builder()
+        .baseUrl("https://raw.githubusercontent.com/android10/Sample-Data/master/Android-CleanArchitecture-Kotlin/")
+        .client(OkHttpClient.Builder().build())
+        .addConverterFactory(GsonConverterFactory.create())
+        .build()
+}

app/src/main/kotlin/com/fernandocejas/sample/core/di/CoreModule.kt

@@ -0,0 +1,14 @@
+package com.fernandocejas.sample.features.login
+
+import com.fernandocejas.sample.core.Feature
+import org.koin.core.module.dsl.singleOf
+import org.koin.dsl.module
+
+fun loginFeature() = object : Feature {
+
+    override fun name() = "login"
+
+    override fun diModule() = module {
+        singleOf(::Authenticator)
+    }
+}

app/src/main/kotlin/com/fernandocejas/sample/features/login/Login.kt

@@ -0,0 +1,27 @@
+package com.fernandocejas.sample.features.movies
+
+import com.fernandocejas.sample.core.Feature
+import org.koin.androidx.viewmodel.dsl.viewModelOf
+import org.koin.core.module.dsl.factoryOf
+import org.koin.dsl.bind
+import org.koin.dsl.module
+
+fun moviesFeature() = object : Feature {
+
+    override fun name() = "movies"
+
+    override fun diModule() = module {
+        // Movies Feature
+        factoryOf(::MoviesService)
+        factory { MoviesRepository.Network(get(), get()) } bind MoviesRepository::class
+        // Movies
+        viewModelOf(::MoviesViewModel)
+        factoryOf(::GetMovies)
+        factoryOf(::MoviesAdapter)
+        // Movie Details
+        viewModelOf(::MovieDetailsViewModel)
+        factoryOf(::GetMovieDetails)
+        factoryOf(::PlayMovie)
+        factoryOf(::MovieDetailsAnimator)
+    }
+}