Dagger2! Finally!

app/build.gradle

@@ -31,14 +31,17 @@ dependencies {
             picasso   : '2.5.2',
             retrofit  : '2.3.0',
             leonids   : '1.3.1',
+            dagger2   : '2.11',
 
             junit     : '4.12',
             mockito   : '2.+',
 
             espresso  : '2.2.2',
             dexmaker  : '2.2.0',
     ]
+    annotationProcessor "com.google.dagger:dagger-compiler:$versions.dagger2"
 
+    compile "com.google.dagger:dagger:$versions.dagger2"
     compile "com.android.support:appcompat-v7:$versions.supportLib"
     compile "com.android.support:design:$versions.supportLib"
     compile "com.squareup.picasso:picasso:$versions.picasso"

app/src/androidTest/java/io/catter2/favorites_activity/FavoritesActivityTest.java

@@ -5,6 +5,7 @@
 import android.support.test.rule.ActivityTestRule;
 import android.support.test.runner.AndroidJUnit4;
 
+import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -13,6 +14,8 @@
 import java.util.List;
 
 import io.catter2.R;
+import io.catter2.di.FavoritesRepoDIModule;
+import io.catter2.di.UserDIComponent;
 import io.catter2.espresso_utils.RecyclerViewItemCountAssertion;
 import io.catter2.favorites.FavoritesRepository;
 import io.catter2.favorites.GetFavoritesUseCase;
@@ -26,6 +29,12 @@ public class FavoritesActivityTest {
     public ActivityTestRule<FavoritesActivity> activityRule =
             new ActivityTestRule<>(FavoritesActivity.class, true, false /* Do not launch activity! */);
 
+    @BeforeClass
+    public static void beforeClass() {
+        // Warning: The AppDIComponent is still being created by the 'App' class!
+        UserDIComponent.initialize(mock(FavoritesRepoDIModule.class));
+    }
+
     @Test
     public void testThereAreThreeImages() {
         final ArrayList<String> expectedUrls = new ArrayList<>();

app/src/androidTest/java/io/catter2/list_activity/ListActivityTest.java

@@ -6,6 +6,7 @@
 import android.support.test.rule.ActivityTestRule;
 import android.support.test.runner.AndroidJUnit4;
 
+import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -16,6 +17,8 @@
 import io.catter2.R;
 import io.catter2.cat_api.FetchCatImagesUseCase;
 import io.catter2.cat_api.TheCatAPI;
+import io.catter2.di.FavoritesRepoDIModule;
+import io.catter2.di.UserDIComponent;
 import io.catter2.espresso_utils.RecyclerViewItemCountAssertion;
 import io.catter2.favorites.AddFavoriteUseCase;
 import io.catter2.favorites.FavoritesRepository;
@@ -34,6 +37,12 @@ public class ListActivityTest {
     public ActivityTestRule<ListActivity> activityRule =
             new ActivityTestRule<>(ListActivity.class, true, false /* Do not launch activity! */);
 
+    @BeforeClass
+    public static void beforeClass() {
+        // Warning: The AppDIComponent is still being created by the 'App' class!
+        UserDIComponent.initialize(mock(FavoritesRepoDIModule.class));
+    }
+
     @Test
     public void testThereAreThreeImages() {
         final ArrayList<String> expectedUrls = new ArrayList<>();

app/src/main/java/io/catter2/App.java

@@ -7,6 +7,7 @@
 import io.catter2.di.AppDIComponent;
 import io.catter2.di.AppDIModule;
 import io.catter2.di.CachedRetrofitCatApiDIModule;
+import io.catter2.di.RetrofitCatApiDIModule;
 
 public class App extends Application {
     @Override
@@ -21,5 +22,8 @@ public Context provideAppContext() {
             }
         };
         AppDIComponent.initialize(appDIModule, new CachedRetrofitCatApiDIModule());
+
+        // Option if you don't want to cache the cat API responses.
+        // AppDIComponent.initialize(appDIModule, new RetrofitCatApiDIModule());
     }
 }

app/src/main/java/io/catter2/LoginActivity.java

@@ -11,7 +11,6 @@
 import android.widget.EditText;
 import android.widget.TextView;
 
-import io.catter2.di.AppDIComponent;
 import io.catter2.di.SharedPrefFavoritesRepoDIModule;
 import io.catter2.di.UserDIComponent;
 import io.catter2.favorites_activity.FavoritesActivity;
@@ -70,7 +69,7 @@ private void attemptLogin() {
         String token = uc.login(username, password);
 
         if (token != null) {
-            UserDIComponent.initialize(new SharedPrefFavoritesRepoDIModule(AppDIComponent.get(), token));
+            UserDIComponent.initialize(new SharedPrefFavoritesRepoDIModule(token));
             FavoritesActivity.launch(this);
         } else {
             errorTv.setVisibility(View.VISIBLE);

app/src/main/java/io/catter2/di/AppDIComponent.java

@@ -2,9 +2,14 @@
 
 import android.content.Context;
 
+import javax.inject.Singleton;
+
+import dagger.Component;
 import io.catter2.cat_api.TheCatAPI;
 
-public class AppDIComponent {
+@Singleton
+@Component(modules = {AppDIModule.class, TheCatAPIDIModule.class})
+public abstract class AppDIComponent {
     private static AppDIComponent instance;
 
     public static AppDIComponent get() {
@@ -15,31 +20,14 @@ public static void initialize(AppDIModule appDIModule, TheCatAPIDIModule theCatA
         if (AppDIComponent.get() != null) {
             throw new RuntimeException("AppDIComponent already initialized.");
         }
-        AppDIComponent.instance = new AppDIComponent(appDIModule, theCatAPIDIModule);
+        AppDIComponent.instance = DaggerAppDIComponent
+                .builder()
+                .appDIModule(appDIModule)
+                .theCatAPIDIModule(theCatAPIDIModule)
+                .build();
     }
 
-    private AppDIModule appDIModule;
-    private TheCatAPIDIModule theCatAPIDIModule;
-
-    private Context appContext;
-    private TheCatAPI theCatAPI;
+    abstract public Context getAppContext();
 
-    public AppDIComponent(AppDIModule appDIModule, TheCatAPIDIModule theCatAPIDIModule) {
-        this.appDIModule = appDIModule;
-        this.theCatAPIDIModule = theCatAPIDIModule;
-    }
-
-    public Context getAppContext() {
-        if (appContext == null) {
-            appContext = appDIModule.provideAppContext();
-        }
-        return appContext;
-    }
-
-    public TheCatAPI getTheCatAPI() {
-        if (theCatAPI == null) {
-            theCatAPI = theCatAPIDIModule.provideTheCatAPI();
-        }
-        return theCatAPI;
-    }
+    abstract public TheCatAPI getTheCatAPI();
 }

app/src/main/java/io/catter2/di/AppDIModule.java

@@ -2,6 +2,16 @@
 
 import android.content.Context;
 
-public interface AppDIModule {
-    Context provideAppContext();
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AppDIModule {
+    @Provides
+    @Singleton
+    public Context provideAppContext() {
+        throw new EmptyModuleException();
+    }
 }

app/src/main/java/io/catter2/di/CachedRetrofitCatApiDIModule.java

@@ -4,7 +4,7 @@
 import io.catter2.cat_api.RetrofitTheCatAPI;
 import io.catter2.cat_api.TheCatAPI;
 
-public class CachedRetrofitCatApiDIModule implements TheCatAPIDIModule {
+public class CachedRetrofitCatApiDIModule extends TheCatAPIDIModule {
     @Override
     public TheCatAPI provideTheCatAPI() {
         return provideTheCatAPICached(provideTheCatAPIRetrofit());

app/src/main/java/io/catter2/di/EmptyModuleException.java

@@ -0,0 +1,4 @@
+package io.catter2.di;
+
+public class EmptyModuleException extends RuntimeException {
+}

app/src/main/java/io/catter2/di/FavoritesRepoDIModule.java

@@ -1,9 +1,26 @@
 package io.catter2.di;
 
+import android.content.Context;
+
+import javax.inject.Named;
+
+import dagger.Module;
+import dagger.Provides;
 import io.catter2.favorites.FavoritesRepository;
 
-public interface FavoritesRepoDIModule {
-    AppDIComponent getAppDIComponent();
+@Module
+public class FavoritesRepoDIModule {
+    @Provides
+    @UserScope
+    public FavoritesRepository provideFavoritesRepository(
+            Context appContext, @Named("UserToken") String userToken) {
+        throw new EmptyModuleException();
+    }
 
-    FavoritesRepository provideFavoritesRepository();
+    @Provides
+    @Named("UserToken")
+    @UserScope
+    public String provideUserToken() {
+        throw new EmptyModuleException();
+    }
 }

app/src/main/java/io/catter2/di/RetrofitCatApiDIModule.java

@@ -0,0 +1,10 @@
+package io.catter2.di;
+
+import io.catter2.cat_api.TheCatAPI;
+
+public class RetrofitCatApiDIModule extends CachedRetrofitCatApiDIModule {
+    @Override
+    public TheCatAPI provideTheCatAPI() {
+        return super.provideTheCatAPIRetrofit();
+    }
+}

app/src/main/java/io/catter2/di/SharedPrefFavoritesRepoDIModule.java

@@ -1,27 +1,23 @@
 package io.catter2.di;
 
+import android.content.Context;
+
 import io.catter2.favorites.FavoritesRepository;
 import io.catter2.favorites.SharedPrefFavoritesRepository;
 
-public class SharedPrefFavoritesRepoDIModule implements FavoritesRepoDIModule {
-    private AppDIComponent appDIComponent;
+public class SharedPrefFavoritesRepoDIModule extends FavoritesRepoDIModule {
     private String userToken;
 
-    public SharedPrefFavoritesRepoDIModule(AppDIComponent appDIComponent, String userToken) {
-        this.appDIComponent = appDIComponent;
+    public SharedPrefFavoritesRepoDIModule(String userToken) {
         this.userToken = userToken;
     }
 
     @Override
-    public AppDIComponent getAppDIComponent() {
-        return this.appDIComponent;
+    public FavoritesRepository provideFavoritesRepository(Context appContext, String userToken) {
+        return new SharedPrefFavoritesRepository(appContext, userToken);
     }
 
     @Override
-    public FavoritesRepository provideFavoritesRepository() {
-        return new SharedPrefFavoritesRepository(appDIComponent.getAppContext(), provideUserToken());
-    }
-
     public String provideUserToken() {
         return this.userToken;
     }

app/src/main/java/io/catter2/di/TheCatAPIDIModule.java

@@ -1,7 +1,16 @@
 package io.catter2.di;
 
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
 import io.catter2.cat_api.TheCatAPI;
 
-public interface TheCatAPIDIModule {
-    TheCatAPI provideTheCatAPI();
+@Module
+public class TheCatAPIDIModule {
+    @Provides
+    @Singleton
+    public TheCatAPI provideTheCatAPI() {
+        throw new EmptyModuleException();
+    }
 }

app/src/main/java/io/catter2/di/UserDIComponent.java

@@ -1,9 +1,12 @@
 package io.catter2.di;
 
-import io.catter2.cat_api.TheCatAPI;
+import dagger.Component;
 import io.catter2.favorites.FavoritesRepository;
 
-public class UserDIComponent {
+@UserScope
+@Component(modules = FavoritesRepoDIModule.class,
+        dependencies = AppDIComponent.class)
+public abstract class UserDIComponent extends AppDIComponent {
     private static UserDIComponent instance;
 
     public static UserDIComponent get() {
@@ -14,30 +17,19 @@ public static void initialize(FavoritesRepoDIModule module) {
         if (UserDIComponent.get() != null) {
             throw new RuntimeException("UserDIComponent already initialized.");
         }
-        UserDIComponent.instance = new UserDIComponent(module);
+        UserDIComponent.instance = DaggerUserDIComponent.builder()
+                .appDIComponent(AppDIComponent.get())
+                .favoritesRepoDIModule(module)
+                .build();
     }
 
-    private FavoritesRepoDIModule module;
-    private FavoritesRepository favoritesRepository;
-
-    private UserDIComponent(FavoritesRepoDIModule module) {
-        this.module = module;
-    }
-
-    public TheCatAPI getTheCatAPIService() {
-        return this.module.getAppDIComponent().getTheCatAPI();
-    }
-
-    public FavoritesRepository getFavoritesRepository() {
-        if (favoritesRepository == null) {
-            favoritesRepository = module.provideFavoritesRepository();
-        }
-        return favoritesRepository;
-    }
+    public abstract FavoritesRepository getFavoritesRepository();
 
     public void close() {
+        final FavoritesRepository favoritesRepository = getFavoritesRepository();
         if (favoritesRepository != null) {
             favoritesRepository.clearChangeListener();
         }
+        UserDIComponent.instance = null;
     }
 }

app/src/main/java/io/catter2/di/UserScope.java

@@ -0,0 +1,7 @@
+package io.catter2.di;
+
+import javax.inject.Scope;
+
+@Scope
+public @interface UserScope {
+}

app/src/main/java/io/catter2/favorites_activity/FavoritesActivity.java

@@ -13,10 +13,12 @@
 
 import java.util.List;
 
+import javax.inject.Inject;
+
 import io.catter2.ImagesRvAdapter;
-import io.catter2.list_activity.ListActivity;
 import io.catter2.R;
 import io.catter2.favorites.GetFavoritesUseCase;
+import io.catter2.list_activity.ListActivity;
 
 public class FavoritesActivity extends AppCompatActivity {
 
@@ -27,15 +29,12 @@ static public void launch(Context context) {
         context.startActivity(intent);
     }
 
+    @Inject
+    public GetFavoritesUseCase getFavoritesUseCase;
+
     private RecyclerView recyclerView;
     private ImagesRvAdapter rvAdapter;
 
-    private GetFavoritesUseCase getFavoritesUseCase;
-
-    public void injectGetFavoritesUserCase(GetFavoritesUseCase useCase) {
-        this.getFavoritesUseCase = useCase;
-    }
-
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -57,7 +56,7 @@ public void onClick(View view) {
         rvAdapter = new ImagesRvAdapter(null);
         recyclerView.setAdapter(rvAdapter);
 
-        new FavoritesActivityDIComponent().inject(this);
+        FavoritesActivityDIComponent.initializeAndInject(this);
     }
 
     @Override