Generify UseCase<T>

Author: android10

domain/src/main/java/com/fernandocejas/android10/sample/domain/interactor/GetUserDetails.java

@@ -28,9 +28,8 @@
  * This class is an implementation of {@link UseCase} that represents a use case for
  * retrieving data related to an specific {@link User}.
  */
-public class GetUserDetails extends UseCase {
+public class GetUserDetails extends UseCase<User> {
 
-  public static final String NAME = "userDetails";
   public static final String PARAM_USER_ID_KEY = "userId";
 
   @VisibleForTesting
@@ -39,13 +38,13 @@ public class GetUserDetails extends UseCase {
   private final UserRepository userRepository;
 
   @Inject
-  public GetUserDetails(UserRepository userRepository, ThreadExecutor threadExecutor,
+  GetUserDetails(UserRepository userRepository, ThreadExecutor threadExecutor,
       PostExecutionThread postExecutionThread) {
     super(threadExecutor, postExecutionThread);
     this.userRepository = userRepository;
   }
 
-  @Override protected Observable buildUseCaseObservable(Optional<Params> params) {
+  @Override protected Observable<User> buildUseCaseObservable(Optional<Params> params) {
     if (params.isPresent()) {
       final int userId = params.get().getInt(PARAM_USER_ID_KEY, PARAM_USER_ID_DEFAULT_VALUE);
       return this.userRepository.user(userId);

domain/src/main/java/com/fernandocejas/android10/sample/domain/interactor/GetUserList.java

@@ -21,15 +21,14 @@
 import com.fernandocejas.android10.sample.domain.repository.UserRepository;
 import com.fernandocejas.arrow.optional.Optional;
 import io.reactivex.Observable;
+import java.util.List;
 import javax.inject.Inject;
 
 /**
  * This class is an implementation of {@link UseCase} that represents a use case for
  * retrieving a collection of all {@link User}.
  */
-public class GetUserList extends UseCase {
-
-  public static final String NAME = "userList";
+public class GetUserList extends UseCase<List<User>> {
 
   private final UserRepository userRepository;
 
@@ -40,7 +39,7 @@ public class GetUserList extends UseCase {
     this.userRepository = userRepository;
   }
 
-  @Override public Observable buildUseCaseObservable(Optional<Params> params) {
+  @Override public Observable<List<User>> buildUseCaseObservable(Optional<Params> params) {
     return this.userRepository.users();
   }
 }

domain/src/main/java/com/fernandocejas/android10/sample/domain/interactor/UseCase.java

@@ -33,7 +33,7 @@
  * By convention each UseCase implementation will return the result using a {@link DisposableObserver}
  * that will execute its job in a background thread and will post the result in the UI thread.
  */
-public abstract class UseCase {
+public abstract class UseCase<T> {
 
   private final ThreadExecutor threadExecutor;
   private final PostExecutionThread postExecutionThread;
@@ -48,7 +48,7 @@ public abstract class UseCase {
   /**
    * Builds an {@link Observable} which will be used when executing the current {@link UseCase}.
    */
-  protected abstract Observable buildUseCaseObservable(Optional<Params> params);
+  abstract Observable<T> buildUseCaseObservable(Optional<Params> params);
 
   /**
    * Executes the current use case.
@@ -57,9 +57,8 @@ public abstract class UseCase {
    * by {@link #buildUseCaseObservable(Optional)} ()} method.
    * @param params Parameters used to build execute this use case.
    */
-  @SuppressWarnings("unchecked")
-  public void execute(DisposableObserver observer, Params params) {
-    final Observable<?> observable = this.buildUseCaseObservable(Optional.of(params))
+  public void execute(DisposableObserver<T> observer, Params params) {
+    final Observable<T> observable = this.buildUseCaseObservable(Optional.of(params))
         .subscribeOn(Schedulers.from(threadExecutor))
         .observeOn(postExecutionThread.getScheduler());
     addDisposable(observable.subscribeWith(observer));

domain/src/test/java/com/fernandocejas/android10/sample/domain/interactor/UseCaseTest.java

@@ -63,7 +63,7 @@ public void testSubscriptionWhenExecutingUseCase() {
     assertThat(testObserver.isDisposed()).isTrue();
   }
 
-  private static class UseCaseTestClass extends UseCase {
+  private static class UseCaseTestClass extends UseCase<Object> {
 
     UseCaseTestClass(ThreadExecutor threadExecutor, PostExecutionThread postExecutionThread) {
       super(threadExecutor, postExecutionThread);

presentation/src/main/java/com/fernandocejas/android10/sample/presentation/internal/di/modules/UserModule.java

@@ -15,16 +15,7 @@
  */
 package com.fernandocejas.android10.sample.presentation.internal.di.modules;
 
-import com.fernandocejas.android10.sample.domain.executor.PostExecutionThread;
-import com.fernandocejas.android10.sample.domain.executor.ThreadExecutor;
-import com.fernandocejas.android10.sample.domain.interactor.GetUserDetails;
-import com.fernandocejas.android10.sample.domain.interactor.GetUserList;
-import com.fernandocejas.android10.sample.domain.interactor.UseCase;
-import com.fernandocejas.android10.sample.domain.repository.UserRepository;
-import com.fernandocejas.android10.sample.presentation.internal.di.PerActivity;
 import dagger.Module;
-import dagger.Provides;
-import javax.inject.Named;
 
 /**
  * Dagger module that provides user related collaborators.
@@ -33,15 +24,4 @@
 public class UserModule {
 
   public UserModule() {}
-
-  @Provides @PerActivity @Named(GetUserList.NAME) UseCase provideGetUserListUseCase(
-      GetUserList getUserList) {
-    return getUserList;
-  }
-
-  @Provides @PerActivity @Named(GetUserDetails.NAME) UseCase provideGetUserDetailsUseCase(
-      UserRepository userRepository, ThreadExecutor threadExecutor,
-      PostExecutionThread postExecutionThread) {
-    return new GetUserDetails(userRepository, threadExecutor, postExecutionThread);
-  }
 }

presentation/src/main/java/com/fernandocejas/android10/sample/presentation/presenter/UserDetailsPresenter.java

@@ -21,15 +21,13 @@
 import com.fernandocejas.android10.sample.domain.exception.ErrorBundle;
 import com.fernandocejas.android10.sample.domain.interactor.DefaultObserver;
 import com.fernandocejas.android10.sample.domain.interactor.GetUserDetails;
-import com.fernandocejas.android10.sample.domain.interactor.UseCase;
 import com.fernandocejas.android10.sample.domain.interactor.Params;
 import com.fernandocejas.android10.sample.presentation.exception.ErrorMessageFactory;
 import com.fernandocejas.android10.sample.presentation.internal.di.PerActivity;
 import com.fernandocejas.android10.sample.presentation.mapper.UserModelDataMapper;
 import com.fernandocejas.android10.sample.presentation.model.UserModel;
 import com.fernandocejas.android10.sample.presentation.view.UserDetailsView;
 import javax.inject.Inject;
-import javax.inject.Named;
 
 /**
  * {@link Presenter} that controls communication between views and models of the presentation
@@ -40,11 +38,11 @@ public class UserDetailsPresenter implements Presenter {
 
   private UserDetailsView viewDetailsView;
 
-  private final UseCase getUserDetailsUseCase;
+  private final GetUserDetails getUserDetailsUseCase;
   private final UserModelDataMapper userModelDataMapper;
 
   @Inject
-  public UserDetailsPresenter(@Named(GetUserDetails.NAME) UseCase getUserDetailsUseCase,
+  public UserDetailsPresenter(GetUserDetails getUserDetailsUseCase,
       UserModelDataMapper userModelDataMapper) {
     this.getUserDetailsUseCase = getUserDetailsUseCase;
     this.userModelDataMapper = userModelDataMapper;

presentation/src/main/java/com/fernandocejas/android10/sample/presentation/presenter/UserListPresenter.java

@@ -21,7 +21,6 @@
 import com.fernandocejas.android10.sample.domain.exception.ErrorBundle;
 import com.fernandocejas.android10.sample.domain.interactor.DefaultObserver;
 import com.fernandocejas.android10.sample.domain.interactor.GetUserList;
-import com.fernandocejas.android10.sample.domain.interactor.UseCase;
 import com.fernandocejas.android10.sample.domain.interactor.Params;
 import com.fernandocejas.android10.sample.presentation.exception.ErrorMessageFactory;
 import com.fernandocejas.android10.sample.presentation.internal.di.PerActivity;
@@ -31,7 +30,6 @@
 import java.util.Collection;
 import java.util.List;
 import javax.inject.Inject;
-import javax.inject.Named;
 
 /**
  * {@link Presenter} that controls communication between views and models of the presentation
@@ -42,11 +40,11 @@ public class UserListPresenter implements Presenter {
 
   private UserListView viewListView;
 
-  private final UseCase getUserListUseCase;
+  private final GetUserList getUserListUseCase;
   private final UserModelDataMapper userModelDataMapper;
 
   @Inject
-  public UserListPresenter(@Named(GetUserList.NAME) UseCase getUserListUserCase,
+  public UserListPresenter(GetUserList getUserListUserCase,
       UserModelDataMapper userModelDataMapper) {
     this.getUserListUseCase = getUserListUserCase;
     this.userModelDataMapper = userModelDataMapper;