[스캇] 1단계 자동 DI 미션 제출합니다

app/build.gradle.kts

@@ -23,7 +23,7 @@ android {
             isMinifyEnabled = false
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
-                "proguard-rules.pro"
+                "proguard-rules.pro",
             )
         }
     }
@@ -68,4 +68,5 @@ dependencies {
     implementation("com.github.bumptech.glide:glide:4.15.1")
     // Robolectric
     testImplementation("org.robolectric:robolectric:4.9")
+    implementation(kotlin("reflect"))
 }

app/src/main/AndroidManifest.xml

@@ -5,6 +5,7 @@
     <uses-permission android:name="android.permission.INTERNET" />
 
     <application
+        android:name=".ShoppingApplication"
         android:allowBackup="true"
         android:dataExtractionRules="@xml/data_extraction_rules"
         android:fullBackupContent="@xml/backup_rules"

app/src/main/java/woowacourse/shopping/ShoppingApplication.kt

@@ -0,0 +1,22 @@
+package woowacourse.shopping
+
+import android.app.Application
+import woowacourse.shopping.data.CartRepositoryImpl
+import woowacourse.shopping.data.ProductRepositoryImpl
+import woowacourse.shopping.di.module
+import woowacourse.shopping.di.startDI
+import woowacourse.shopping.repository.CartRepository
+import woowacourse.shopping.repository.ProductRepository
+
+class ShoppingApplication : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        val dataModule = module {
+            provide<ProductRepository> { ProductRepositoryImpl() }
+            provide<CartRepository> { CartRepositoryImpl() }
+        }
+        startDI {
+            loadModule(dataModule)
+        }
+    }
+}

app/src/main/java/woowacourse/shopping/data/CartRepository.kt → app/src/main/java/woowacourse/shopping/data/CartRepositoryImpl.kt

@@ -1,20 +1,21 @@
 package woowacourse.shopping.data
 
 import woowacourse.shopping.model.Product
+import woowacourse.shopping.repository.CartRepository
 
 // TODO: Step2 - CartProductDao를 참조하도록 변경
-class CartRepository {
-
-    private val cartProducts: MutableList<Product> = mutableListOf()
-    fun addCartProduct(product: Product) {
+class CartRepositoryImpl(
+    private val cartProducts: MutableList<Product> = mutableListOf(),
+) : CartRepository {
+    override fun addCartProduct(product: Product) {
         cartProducts.add(product)
     }
 
-    fun getAllCartProducts(): List<Product> {
-        return cartProducts.toList()
+    override fun deleteCartProduct(id: Int) {
+        cartProducts.removeAt(id)
     }
 
-    fun deleteCartProduct(id: Int) {
-        cartProducts.removeAt(id)
+    override fun getAllCartProducts(): List<Product> {
+        return cartProducts.toList()
     }
 }

app/src/main/java/woowacourse/shopping/data/ProductRepository.kt → app/src/main/java/woowacourse/shopping/data/ProductRepositoryImpl.kt

@@ -1,28 +1,29 @@
 package woowacourse.shopping.data
 
 import woowacourse.shopping.model.Product
+import woowacourse.shopping.repository.ProductRepository
 
-class ProductRepository {
+class ProductRepositoryImpl : ProductRepository {
 
     private val products: List<Product> = listOf(
         Product(
             name = "우테코 과자",
             price = 10_000,
-            imageUrl = "https://cdn-mart.baemin.com/sellergoods/api/main/df6d76fb-925b-40f8-9d1c-f0920c3c697a.jpg?h=700&w=700"
+            imageUrl = "https://cdn-mart.baemin.com/sellergoods/api/main/df6d76fb-925b-40f8-9d1c-f0920c3c697a.jpg?h=700&w=700",
         ),
         Product(
             name = "우테코 쥬스",
             price = 8_000,
-            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/52dca718-31c5-4f80-bafa-7e300d8c876a.jpg?h=700&w=700"
+            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/52dca718-31c5-4f80-bafa-7e300d8c876a.jpg?h=700&w=700",
         ),
         Product(
             name = "우테코 아이스크림",
             price = 20_000,
-            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/e703c53e-5d01-4b20-bd33-85b5e778e73f.jpg?h=700&w=700"
+            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/e703c53e-5d01-4b20-bd33-85b5e778e73f.jpg?h=700&w=700",
         ),
     )
 
-    fun getAllProducts(): List<Product> {
+    override fun getAllProducts(): List<Product> {
         return products
     }
 }

app/src/main/java/woowacourse/shopping/data/ShoppingDatabase.kt

@@ -3,7 +3,6 @@ package woowacourse.shopping.data
 import androidx.room.Database
 import androidx.room.RoomDatabase
 
-
 @Database(entities = [CartProductEntity::class], version = 1, exportSchema = false)
 abstract class ShoppingDatabase : RoomDatabase() {
     abstract fun cartProductDao(): CartProductDao

app/src/main/java/woowacourse/shopping/di/Injector.kt

@@ -0,0 +1,56 @@
+package woowacourse.shopping.di
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.ViewModelStoreOwner
+import woowacourse.shopping.di.service.DefaultService
+import woowacourse.shopping.di.service.Service
+import woowacourse.shopping.ui.util.ViewModelFactoryUtil
+import java.util.concurrent.ConcurrentHashMap
+import kotlin.reflect.KClass
+
+object Injector {
+    private val services: MutableMap<KClass<*>, Service> = ConcurrentHashMap()
+    lateinit var declarations: Map<KClass<*>, Declaration<Any>>
+
+    fun <T : Any> getService(kClazz: KClass<out T>): Service {
+        return services[kClazz] ?: error(SERVICE_NOT_FOUNT_ERROR_MESSAGE + "$kClazz")
+    }
+
+    fun loadModules(modules: List<Module>) {
+        modules.forEach(::loadModule)
+    }
+
+    fun loadModule(module: Module) {
+        declarations = module.declarationRegistry
+        declarations.forEach { declaration ->
+            val service = getServiceFromDeclaration(declaration.key, declaration.value)
+            addService(service)
+        }
+    }
+
+    private fun addService(service: Service) {
+        services[service.type] = service
+    }
+
+    private fun <T : Any> getServiceFromDeclaration(
+        type: KClass<*>,
+        declaration: Declaration<T>,
+    ): Service {
+        val instance = declaration.invoke()
+        return DefaultService.create(type, instance)
+    }
+
+    private const val SERVICE_NOT_FOUNT_ERROR_MESSAGE = "Unable to find definition of"
+}
+
+fun startDI(block: Injector.() -> Unit) = Injector.apply(block)
+
+inline fun <reified T : Any> get(): T {
+    val service = Injector.getService(T::class)
+    return service.instance as T
+}
+
+inline fun <reified T : ViewModel> ViewModelStoreOwner.viewModel(): Lazy<T> = lazy {
+    ViewModelProvider(this, ViewModelFactoryUtil.viewModelFactory<T>())[T::class.java]
+}

app/src/main/java/woowacourse/shopping/di/Module.kt

@@ -0,0 +1,31 @@
+package woowacourse.shopping.di
+
+import java.util.concurrent.ConcurrentHashMap
+import kotlin.reflect.KClass
+
+typealias Declaration<T> = () -> T
+
+fun module(block: Module.() -> Unit) = Module().apply(block)
+
+// 여러 모듈 생성 가능, 최종적으로 사용할 서비스로 올라가기 전, 모듈의 declarationRegistry 에 임시로 저장한다.
+open class Module {
+    val declarationRegistry: MutableMap<KClass<*>, Declaration<Any>> = ConcurrentHashMap()
+
+    inline fun <reified T : Any> provide(noinline declaration: Declaration<T>) {
+        declarationRegistry[T::class] = declaration
+    }
+
+    // 모듈 내에서 의존성 주입이 필요할 때
+    inline fun <reified T : Any> get(): T {
+        val declaration = declarationRegistry[T::class]
+        var instance = declaration?.invoke()
+
+        if (instance == null) {
+            instance = Injector.declarations[T::class]?.invoke()
+                ?: error("Unable to find declaration of type ${T::class.qualifiedName}")
+        }
+        return instance as T
+    }
+
+    operator fun plus(module: Module) = listOf(module, this)
+}

app/src/main/java/woowacourse/shopping/di/service/DefaultService.kt

@@ -0,0 +1,23 @@
+package woowacourse.shopping.di.service
+
+import kotlin.reflect.KClass
+import kotlin.reflect.full.superclasses
+
+// 최종적으로 Client(Activty 또는 뷰모델) 이 사용할 서비스
+class DefaultService(
+    override val type: KClass<*>,
+    override val instance: Any,
+) : Service {
+    companion object {
+        fun create(type: KClass<*>, instance: Any): Service {
+            if (instance.isMatchWith(type)) {
+                return DefaultService(type, instance)
+            }
+            throw IllegalStateException("MisMatch Type And Instance")
+        }
+
+        private fun Any.isMatchWith(type: KClass<*>): Boolean {
+            return this::class.superclasses.contains(type) || this::class == type
+        }
+    }
+}

app/src/main/java/woowacourse/shopping/di/service/Service.kt

@@ -0,0 +1,8 @@
+package woowacourse.shopping.di.service
+
+import kotlin.reflect.KClass
+
+interface Service {
+    val type: KClass<*>
+    val instance: Any
+}

app/src/main/java/woowacourse/shopping/ui/MainActivity.kt

@@ -5,19 +5,16 @@ import android.os.Bundle
 import android.view.Menu
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
-import androidx.lifecycle.ViewModelProvider
 import woowacourse.shopping.R
 import woowacourse.shopping.databinding.ActivityMainBinding
+import woowacourse.shopping.di.viewModel
 import woowacourse.shopping.ui.cart.CartActivity
 
 class MainActivity : AppCompatActivity() {
 
     private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }
 
-    private val viewModel by lazy {
-        ViewModelProvider(this)[MainViewModel::class.java]
-    }
-
+    private val viewModel: MainViewModel by viewModel()
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(binding.root)
@@ -27,7 +24,6 @@ class MainActivity : AppCompatActivity() {
         setupView()
     }
 
-
     override fun onCreateOptionsMenu(menu: Menu?): Boolean {
         menuInflater.inflate(R.menu.cart_menu, menu)
         menu?.findItem(R.id.cart)?.actionView?.let { view ->
@@ -58,7 +54,7 @@ class MainActivity : AppCompatActivity() {
         viewModel.products.observe(this) {
             val adapter = ProductAdapter(
                 items = it,
-                onClickProduct = viewModel::addCartProduct
+                onClickProduct = viewModel::addCartProduct,
             )
             binding.rvProducts.adapter = adapter
         }

app/src/main/java/woowacourse/shopping/ui/MainViewModel.kt

@@ -3,9 +3,9 @@ package woowacourse.shopping.ui
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
-import woowacourse.shopping.data.CartRepository
-import woowacourse.shopping.data.ProductRepository
 import woowacourse.shopping.model.Product
+import woowacourse.shopping.repository.CartRepository
+import woowacourse.shopping.repository.ProductRepository
 
 class MainViewModel(
     private val productRepository: ProductRepository,
@@ -18,7 +18,6 @@ class MainViewModel(
     private val _onProductAdded: MutableLiveData<Boolean> = MutableLiveData(false)
     val onProductAdded: LiveData<Boolean> get() = _onProductAdded
 
-
     fun addCartProduct(product: Product) {
         cartRepository.addCartProduct(product)
         _onProductAdded.value = true

app/src/main/java/woowacourse/shopping/ui/cart/CartActivity.kt

@@ -3,17 +3,15 @@ package woowacourse.shopping.ui.cart
 import android.os.Bundle
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
-import androidx.lifecycle.ViewModelProvider
 import woowacourse.shopping.R
 import woowacourse.shopping.databinding.ActivityCartBinding
+import woowacourse.shopping.di.viewModel
 
 class CartActivity : AppCompatActivity() {
 
     private val binding by lazy { ActivityCartBinding.inflate(layoutInflater) }
 
-    private val viewModel by lazy {
-        ViewModelProvider(this)[CartViewModel::class.java]
-    }
+    private val viewModel: CartViewModel by viewModel()
 
     private lateinit var dateFormatter: DateFormatter
 
@@ -60,7 +58,7 @@ class CartActivity : AppCompatActivity() {
             val adapter = CartProductAdapter(
                 items = it,
                 dateFormatter = dateFormatter,
-                onClickDelete = viewModel::deleteCartProduct
+                onClickDelete = viewModel::deleteCartProduct,
             )
             binding.rvCartProducts.adapter = adapter
         }

app/src/main/java/woowacourse/shopping/ui/cart/CartViewModel.kt

@@ -3,8 +3,8 @@ package woowacourse.shopping.ui.cart
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
-import woowacourse.shopping.data.CartRepository
 import woowacourse.shopping.model.Product
+import woowacourse.shopping.repository.CartRepository
 
 class CartViewModel(
     private val cartRepository: CartRepository,

app/src/main/java/woowacourse/shopping/ui/util/ViewModelFactoryUtil.kt

@@ -0,0 +1,30 @@
+package woowacourse.shopping.ui.util
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
+import woowacourse.shopping.di.Injector
+import kotlin.reflect.full.primaryConstructor
+import kotlin.reflect.jvm.jvmErasure
+
+object ViewModelFactoryUtil {
+    inline fun <reified T : ViewModel> viewModelFactory(): ViewModelProvider.Factory =
+        viewModelFactory {
+            initializer {
+                // 뷰모델의 주 생성자를 가져와요!!
+                val primaryConstructor =
+                    T::class.primaryConstructor ?: throw IllegalStateException()
+
+                // 뷰 모델의 생성자의 파라미터들을 KClass 로 바꿔줘요!
+                val constructorParameterKClasses =
+                    primaryConstructor.parameters.map { it.type.jvmErasure }
+
+                // 파라미터들의 KClass에 해당하는 객체를 주입해요!
+                val arguments = constructorParameterKClasses.map { kClazz ->
+                    Injector.getService(kClazz).instance
+                }.toTypedArray()
+                primaryConstructor.call(*arguments)
+            }
+        }
+}