Clean architecture on Android

Overview and implementation examples (code snippets) for clean architecture implementation on Android.
Talk @ Droidcon Zagreb 2016

1. Clean architecture 
 on Android Marko Miloš
2. Why … ?
3. Why … ? #ArchitectureMatters
4. Clean architecture Undabot
5. Clean architecture • Independent of frameworks Undabot
6. Clean architecture • Independent of frameworks • Testable Undabot
7. Clean architecture • Independent of frameworks • Testable • Independent of UI Undabot
8. Clean architecture • Independent of frameworks • Testable • Independent of UI • Independent of database / storage Undabot
9. Clean architecture • Independent of frameworks • Testable • Independent of UI • Independent of database / storage • Independent of any external agency Undabot
10. The Dependency Rule Undabot
11. The Dependency Rule Entities Undabot
12. The Dependency Rule Entities UseCase Abstraction Undabot
13. The Dependency Rule Entities UseCase Abstraction Presenter Repository Undabot
14. The Dependency Rule Entities UseCase Abstraction Presenter Repository UI Data source Undabot
15. The Dependency Rule Entities UseCase Abstraction Presenter Repository UI Data source Undabot
16. The Dependency Rule Entities UseCase Abstraction Presenter Repository UI Data source Undabot
17. Layers Entities UseCase Abstraction Presenter Repository UI Data source
18. Layers Entities UseCase Abstraction Presenter Repository UI Data source
19. Layers Entities UseCase Abstraction Presenter Repository UI Data source UseCase / Interactors Entities Abstraction DOMAIN
20. Layers Entities UseCase Abstraction Presenter Repository UI Data source UseCase / Interactors Entities Abstraction DOMAIN Repository Data source DATA
21. Layers Entities UseCase Abstraction Presenter Repository UI Data source UI Presenter PRESENTATION UseCase / Interactors Entities Abstraction DOMAIN Repository Data source DATA
22. Presentation Undabot
23. Presentation Model View Presenter (MVP) Undabot
24. Presentation Model View Presenter (MVP) View • bind data to view • scheduling animations / transitions • propagate user input to presenter • Activity, Fragment, View Undabot
25. Presentation • orchestrate and execute use cases • prepare / format data for the view Model View Presenter (MVP) View • bind data to view • scheduling animations / transitions • propagate user input to presenter • Activity, Fragment, View Presenter Undabot
26. Flow Undabot
27. Flow View Presenter D O M A I N Undabot
28. Flow View Presenter D O M A I N bind(v) Undabot
29. Flow View Presenter D O M A I N bind(v) execute(s) Undabot
30. Flow View Presenter D O M A I N bind(v) execute(s) data Undabot
31. Flow View Presenter D O M A I N bind(v) execute(s) data process
 format Undabot
32. Flow View Presenter D O M A I N bind(v) execute(s) data process
 format display(d) Undabot
33. Flow View Presenter D O M A I N execute(s) data process
 format display(d) [user input] onInput() Undabot
34. Timeline Undabot
35. Timeline • Dagger 2 Undabot
36. Timeline • Dagger 2 • RXJava Undabot
37. Timeline • Dagger 2 • RXJava • Retrolambda Undabot
38. Abstraction Undabot
39. Abstraction public class Timeline {
 List<Tweet> tweets;
 } Undabot
40. Abstraction public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public class Timeline {
 List<Tweet> tweets;
 } Undabot
41. Abstraction public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public class Timeline {
 List<Tweet> tweets;
 } Undabot
42. Abstraction public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } Undabot
43. Abstraction public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelinePresenter extends Presenter<TimelineView> { 
 void onRefresh();
 
 void onTweetSelected(Tweet tweet); 
 } public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } Undabot
44. Abstraction public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelinePresenter extends Presenter<TimelineView> { 
 void onRefresh();
 
 void onTweetSelected(Tweet tweet); 
 } public interface TimelinePresenter extends Presenter<TimelineView> { 
 void onRefresh();
 
 void onTweetSelected(Tweet tweet); 
 } public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } Undabot
45. Abstraction public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelinePresenter extends Presenter<TimelineView> { 
 void onRefresh();
 
 void onTweetSelected(Tweet tweet); 
 } public interface TimelinePresenter extends Presenter<TimelineView> { 
 void onRefresh();
 
 void onTweetSelected(Tweet tweet); 
 } public interface TimelinePresenter extends Presenter<TimelineView> { 
 void onRefresh();
 
 void onTweetSelected(Tweet tweet); 
 } public class Timeline {
 List<Tweet> tweets;
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } public interface TimelineView extends View {
 
 void displayError(String message);
 
 void displayTimeline(List<Tweet> tweets);
 
 } Undabot
46. View implementation Undabot
47. View implementation public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } Undabot
48. View implementation public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } Undabot
49. View implementation public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } Undabot
50. View implementation public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } public class TimelineActivity extends AppCompatActivity implements TimelineView {
 
 @Inject TimelinePresenter timelinePresenter;
 
 SwipeRefreshLayout swipeRefreshLayout;
 
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 
 injectDependencies();
 timelinePresenter.bind(this);
 
 swipeRefreshLayout.setOnRefreshListener(() -> timelinePresenter.onRefresh());
 }
 
 @Override
 public void displayError(String message) {
 /* display error */
 }
 
 @Override
 public void displayTimeline(Timeline timeline) {
 /* setup recycler, adapter etc */
 }
 } Undabot
51. public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } Presenter implementation Undabot
52. Presenter implementation public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } Undabot
53. Presenter implementation public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } Undabot
54. Presenter implementation public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } Undabot
55. Presenter implementation public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } public class TimelinePresenterImpl extends AbsPresenter<TimelineView> implements TimelinePresenter {
 
 private final Navigator navigator;
 private final GetTimelineUseCase useCase;
 
 @Inject
 public TimelinePresenterImpl(Navigator navigator, GetTimelineUseCase useCase) {
 this.navigator = navigator;
 this.useCase = useCase;
 }
 
 @Override
 protected void onBind() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onRefresh() {
 useCase.execute(new TimelineSubscriber());
 }
 
 @Override
 public void onTweetSelected(Tweet tweet) {
 navigator.openTweetDetails(tweet);
 }
 } Undabot
56. Callback / Subscriber Undabot
57. Callback / Subscriber private final class TimelineSubscriber extends Subscriber<Timeline> {
 @Override
 public void onCompleted() {
 }
 
 @Override
 public void onError(Throwable e) {
 view().displayError(ErrorMessageFactory.create(e));
 }
 
 @Override
 public void onNext(Timeline timeline) {
 view().displayTimeline(timeline.tweets);
 }
 } Undabot
58. Callback / Subscriber private final class TimelineSubscriber extends Subscriber<Timeline> {
 @Override
 public void onCompleted() {
 }
 
 @Override
 public void onError(Throwable e) {
 view().displayError(ErrorMessageFactory.create(e));
 }
 
 @Override
 public void onNext(Timeline timeline) {
 view().displayTimeline(timeline.tweets);
 }
 } Undabot
59. Callback / Subscriber private final class TimelineSubscriber extends Subscriber<Timeline> {
 @Override
 public void onCompleted() {
 }
 
 @Override
 public void onError(Throwable e) {
 view().displayError(ErrorMessageFactory.create(e));
 }
 
 @Override
 public void onNext(Timeline timeline) {
 view().displayTimeline(timeline.tweets);
 }
 } private final class TimelineSubscriber extends Subscriber<Timeline> {
 @Override
 public void onCompleted() {
 }
 
 @Override
 public void onError(Throwable e) {
 view().displayError(ErrorMessageFactory.create(e));
 }
 
 @Override
 public void onNext(Timeline timeline) {
 view().displayTimeline(timeline.tweets);
 }
 } Undabot
60. P R E S E N T A T I O N Domain D A T A Undabot
61. P R E S E N T A T I O N Domain D A T A UseCase execute(s) Undabot
62. P R E S E N T A T I O N Domain D A T A UseCase Model execute(s) Undabot
63. P R E S E N T A T I O N Domain D A T A UseCase Abstraction Abstraction Abstraction Model execute(s) Undabot
64. P R E S E N T A T I O N Domain D A T A UseCase Abstraction Abstraction Abstraction Model execute(s) Undabot
65. P R E S E N T A T I O N Domain D A T A UseCase Abstraction Abstraction Abstraction Model Business logic execute(s) Undabot
66. P R E S E N T A T I O N Domain D A T A UseCase Abstraction Abstraction Abstraction Model Business logic execute(s) s.onNext(d)
 s.onError(t) Undabot
67. Model UseCase Abstraction Abstraction Abstraction Model Business logic Undabot
68. Model UseCase Abstraction Abstraction Abstraction Model Business logic public class Tweet {
 private String author;
 private String content;
 
 public Tweet(String author, String content) {
 this.author = author;
 this.content = content;
 }
 } public class Timeline {
 private List<Tweet> tweets;
 
 public Timeline(List<Tweet> tweets) {
 this.tweets = tweets;
 }
 } public class Location {
 private float lat;
 private float lng;
 
 public Location(float lat, float lng) {
 this.lat = lat;
 this.lng = lng;
 }
 } public class Region {
 private Bounds bounds;
 private Location location;
 private Map<Integer, Area> areas;
 
 public Region(Bounds bounds, Location location) {
 this.bounds = bounds;
 this.location = location;
 }
 } Undabot
69. Interactor UseCase Abstraction Abstraction Abstraction Model Business logic Undabot
70. public interface Interactor<T> {
 void execute(Callback<T> callback);
 } Interactor UseCase Abstraction Abstraction Abstraction Model Business logic Undabot
71. Interactor UseCase Abstraction Abstraction Abstraction Model Business logic public interface Interactor<T> {
 void execute(Subscriber<T> subscriber);
 } Undabot
72. Interactor UseCase Abstraction Abstraction Abstraction Model Business logic public interface Interactor<T> {
 void execute(Subscriber<T> subscriber);
 
 Observable<T> execute();
 } Undabot
73. Contract UseCase Abstraction Abstraction Abstraction Model Business logic abstract class UseCase<T> implements Interactor<T> {
 
 private final ThreadExecutor threadExecutor;
 private final PostExecutionThread postExecutionThread;
 
 private Subscription subscription = Subscriptions.empty();
 
 public UseCase(ThreadExecutor threadExecutor, PostExecutionThread postExecutionThread) {
 this.threadExecutor = threadExecutor;
 this.postExecutionThread = postExecutionThread;
 }
 
 abstract Observable<T> createObservable();
 
 @Override
 public void execute(Subscriber<T> subscriber) {
 this.subscription = createObservable()
 .subscribeOn(Schedulers.from(threadExecutor))
 .observeOn(postExecutionThread.getScheduler())
 .subscribe(subscriber);
 }
 
 @Override
 public Observable<T> execute() {
 return createObservable();
 }
 
 public void unsubscribe() {
 if (!subscription.isUnsubscribed()) {
 subscription.unsubscribe();
 }
 }
 } Undabot
74. Contract UseCase Abstraction Abstraction Abstraction Model Business logic abstract class UseCase<T> implements Interactor<T> {
 
 private final ThreadExecutor threadExecutor;
 private final PostExecutionThread postExecutionThread;
 
 private Subscription subscription = Subscriptions.empty();
 
 public UseCase(ThreadExecutor threadExecutor, PostExecutionThread postExecutionThread) {
 this.threadExecutor = threadExecutor;
 this.postExecutionThread = postExecutionThread;
 }
 
 abstract Observable<T> createObservable();
 
 @Override
 public void execute(Subscriber<T> subscriber) {
 this.subscription = createObservable()
 .subscribeOn(Schedulers.from(threadExecutor))
 .observeOn(postExecutionThread.getScheduler())
 .subscribe(subscriber);
 }
 
 @Override
 public Observable<T> execute() {
 return createObservable();
 }
 
 public void unsubscribe() {
 if (!subscription.isUnsubscribed()) {
 subscription.unsubscribe();
 }
 }
 } Undabot
75. Contract UseCase Abstraction Abstraction Abstraction Model Business logic abstract class UseCase<T> implements Interactor<T> {
 
 private final ThreadExecutor threadExecutor;
 private final PostExecutionThread postExecutionThread;
 
 private Subscription subscription = Subscriptions.empty();
 
 public UseCase(ThreadExecutor threadExecutor, PostExecutionThread postExecutionThread) {
 this.threadExecutor = threadExecutor;
 this.postExecutionThread = postExecutionThread;
 }
 
 abstract Observable<T> createObservable();
 
 @Override
 public void execute(Subscriber<T> subscriber) {
 this.subscription = createObservable()
 .subscribeOn(Schedulers.from(threadExecutor))
 .observeOn(postExecutionThread.getScheduler())
 .subscribe(subscriber);
 }
 
 @Override
 public Observable<T> execute() {
 return createObservable();
 }
 
 public void unsubscribe() {
 if (!subscription.isUnsubscribed()) {
 subscription.unsubscribe();
 }
 }
 } Undabot
76. Contract UseCase Abstraction Abstraction Abstraction Model Business logic abstract class UseCase<T> implements Interactor<T> {
 
 private final ThreadExecutor threadExecutor;
 private final PostExecutionThread postExecutionThread;
 
 private Subscription subscription = Subscriptions.empty();
 
 public UseCase(ThreadExecutor threadExecutor, PostExecutionThread postExecutionThread) {
 this.threadExecutor = threadExecutor;
 this.postExecutionThread = postExecutionThread;
 }
 
 abstract Observable<T> createObservable();
 
 @Override
 public void execute(Subscriber<T> subscriber) {
 this.subscription = createObservable()
 .subscribeOn(Schedulers.from(threadExecutor))
 .observeOn(postExecutionThread.getScheduler())
 .subscribe(subscriber);
 }
 
 @Override
 public Observable<T> execute() {
 return createObservable();
 }
 
 public void unsubscribe() {
 if (!subscription.isUnsubscribed()) {
 subscription.unsubscribe();
 }
 }
 } Undabot
77. Implementation UseCase Abstraction Abstraction Abstraction Model Business logic Undabot
78. Implementation UseCase Abstraction Abstraction Abstraction Model Business logic public class GetTimelineUseCase extends UseCase<Timeline> {
 
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.timelineRepository = timelineRepository;
 }
 
 @Override
 Observable<Timeline> createObservable() {
 return timelineRepository.getTimeline();
 }
 } Undabot
79. Implementation UseCase Abstraction Abstraction Abstraction Model Business logic public class GetTimelineUseCase extends UseCase<Timeline> {
 
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.timelineRepository = timelineRepository;
 }
 
 @Override
 Observable<Timeline> createObservable() {
 return timelineRepository.getTimeline();
 }
 } Undabot
80. Implementation UseCase Abstraction Abstraction Abstraction Model Business logic public class GetTimelineUseCase extends UseCase<Timeline> {
 
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.timelineRepository = timelineRepository;
 }
 
 @Override
 Observable<Timeline> createObservable() {
 return timelineRepository.getTimeline();
 }
 } Undabot
81. Abstraction UseCase Abstraction Abstraction Abstraction Model Business logic Undabot
82. Abstraction UseCase Abstraction Abstraction Abstraction Model Business logic public interface TimelineRepository {
 
 Observable<Timeline> getTimeline();
 
 Observable<Timeline> getTimeline(String hashTag);
 
 Observable<Timeline> getTimeline(Region region);
 
 } Undabot
83. Business logic UseCase Abstraction Abstraction Abstraction Model Business logic Undabot
84. Business logic UseCase Abstraction Abstraction Abstraction Model Business logic public final class LocationOperations {
 
 /* Initialization */
 
 public Region toRegion(Location location) {
 /* Business logic implementation */ 
 }
 } Undabot
85. Regional timeline feature
86. Regional timeline feature get current location location available ? get default location no yes
87. Regional timeline feature calculate region get current location location available ? get default location no yes
88. Regional timeline feature get timeline for region calculate region get current location location available ? get default location no yes
89. Regional timeline feature get timeline for region calculate region get current location location available ? get default location no yes GetLocationUseCase
90. Regional timeline feature get timeline for region calculate region get current location location available ? get default location no yes GetLocationUseCase Business 
 logic
91. Regional timeline feature get timeline for region calculate region get current location location available ? get default location no yes GetLocationUseCase Business 
 logic GetRegionalTimelineUseCase
92. Location get current location location available ? get default location no yes Undabot
93. Location get current location location available ? get default location no yes public class GetLocationUseCase extends UseCase<Location> {
 
 private final LocationProvider locationProvider;
 
 @Inject
 public GetLocationUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 LocationProvider locationProvider) {
 super(threadExecutor, postExecutionThread);
 this.locationProvider = locationProvider;
 }
 
 @Override
 Observable<Location> createObservable() {
 return Observable
 .concat(locationProvider.getCurrentLocation(), locationProvider.getDefaultLocation())
 .first(location -> location != null);
 }
 } Undabot
94. Location get current location location available ? get default location no yes public class GetLocationUseCase extends UseCase<Location> {
 
 private final LocationProvider locationProvider;
 
 @Inject
 public GetLocationUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 LocationProvider locationProvider) {
 super(threadExecutor, postExecutionThread);
 this.locationProvider = locationProvider;
 }
 
 @Override
 Observable<Location> createObservable() {
 return Observable
 .concat(locationProvider.getCurrentLocation(), locationProvider.getDefaultLocation())
 .first(location -> location != null);
 }
 } Undabot
95. Location get current location location available ? get default location no yes public class GetLocationUseCase extends UseCase<Location> {
 
 private final LocationProvider locationProvider;
 
 @Inject
 public GetLocationUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 LocationProvider locationProvider) {
 super(threadExecutor, postExecutionThread);
 this.locationProvider = locationProvider;
 }
 
 @Override
 Observable<Location> createObservable() {
 return Observable
 .concat(locationProvider.getCurrentLocation(), locationProvider.getDefaultLocation())
 .first(location -> location != null);
 }
 } Undabot
96. Location get current location location available ? get default location no yes public class GetLocationUseCase extends UseCase<Location> {
 
 private final LocationProvider locationProvider;
 
 @Inject
 public GetLocationUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 LocationProvider locationProvider) {
 super(threadExecutor, postExecutionThread);
 this.locationProvider = locationProvider;
 }
 
 @Override
 Observable<Location> createObservable() {
 return Observable
 .concat(locationProvider.getCurrentLocation(), locationProvider.getDefaultLocation())
 .first(location -> location != null);
 }
 } public interface LocationProvider {
 
 Observable<Location> getCurrentLocation();
 
 Observable<Location> getDefaultLocation();
 
 } Undabot
97. Regional timeline feature get timeline for region calculate region get current location location available ? get default location no yes GetLocationUseCase Business 
 logic GetRegionalTimelineUseCase
98. Regional timeline use case GetRegionalTimelineUseCase Undabot
99. Regional timeline use case public class GetRegionalTimelineUseCase extends UseCase<Timeline> {
 
 private final GetLocationUseCase locationUseCase;
 private final LocationOperations locationOperations;
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetRegionalTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 GetLocationUseCase locationUseCase,
 LocationOperations locationOperations,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.locationUseCase = locationUseCase;
 this.locationOperations = locationOperations;
 this.timelineRepository = timelineRepository;
 }
 
 
 } GetRegionalTimelineUseCase Undabot
100. Regional timeline use case @Override
 Observable<Timeline> createObservable() {
 return locationUseCase
 .execute()
 .map(new Func1<Location, Region>() {
 @Override
 public Region call(Location location) {
 return locationOperations.toRegion(location);
 }
 })
 .flatMap(new Func1<Region, Observable<Timeline>>() {
 @Override
 public Observable<Timeline> call(Region region) {
 return timelineRepository.getTimeline(region);
 }
 });
 } public class GetRegionalTimelineUseCase extends UseCase<Timeline> {
 
 private final GetLocationUseCase locationUseCase;
 private final LocationOperations locationOperations;
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetRegionalTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 GetLocationUseCase locationUseCase,
 LocationOperations locationOperations,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.locationUseCase = locationUseCase;
 this.locationOperations = locationOperations;
 this.timelineRepository = timelineRepository;
 }
 
 
 } GetRegionalTimelineUseCase Undabot
101. Regional timeline use case @Override
 Observable<Timeline> createObservable() {
 return locationUseCase
 .execute()
 .map(location -> locationOperations.toRegion(location))
 .flatMap(region -> timelineRepository.getTimeline(region));
 } public class GetRegionalTimelineUseCase extends UseCase<Timeline> {
 
 private final GetLocationUseCase locationUseCase;
 private final LocationOperations locationOperations;
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetRegionalTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 GetLocationUseCase locationUseCase,
 LocationOperations locationOperations,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.locationUseCase = locationUseCase;
 this.locationOperations = locationOperations;
 this.timelineRepository = timelineRepository;
 }
 
 
 } GetRegionalTimelineUseCase Undabot
102. Regional timeline use case @Override
 Observable<Timeline> createObservable() {
 return locationUseCase
 .execute()
 .map(locationOperations::toRegion)
 .flatMap(timelineRepository::getTimeline);
 } public class GetRegionalTimelineUseCase extends UseCase<Timeline> {
 
 private final GetLocationUseCase locationUseCase;
 private final LocationOperations locationOperations;
 private final TimelineRepository timelineRepository;
 
 @Inject
 public GetRegionalTimelineUseCase(ThreadExecutor threadExecutor,
 PostExecutionThread postExecutionThread,
 GetLocationUseCase locationUseCase,
 LocationOperations locationOperations,
 TimelineRepository timelineRepository) {
 super(threadExecutor, postExecutionThread);
 this.locationUseCase = locationUseCase;
 this.locationOperations = locationOperations;
 this.timelineRepository = timelineRepository;
 }
 
 
 } GetRegionalTimelineUseCase Undabot
103. Data P R E S E N T A T I O N D O M A I N Undabot
104. Data P R E S E N T A T I O N D O M A I N Repository Undabot
105. Data P R E S E N T A T I O N D O M A I N Repository Data source Undabot
106. Data P R E S E N T A T I O N D O M A I N Repository Data source Network Disk DB Memory Undabot
107. Data P R E S E N T A T I O N D O M A I N Cache ORM Cache Retrofit Repository Data source Network Disk DB Memory Undabot
108. Data P R E S E N T A T I O N D O M A I N Cache ORM Cache Retrofit Repository Data source Network Disk DB Memory Data source factory Undabot
109. Data P R E S E N T A T I O N D O M A I N Cache ORM Cache Retrofit Repository Data source Network Disk DB Memory Undabot
110. Data source Repository Data source Network Disk DB Memory Undabot
111. Data source public interface TimelineDataSource {
 
 Observable<Timeline> getTimeline();
 
 Observable<Timeline> getTimeline(String hashTag);
 
 Observable<Timeline> getTimeline(Region region);
 
 // Other
 } Repository Data source Network Disk DB Memory Undabot
112. Network implementation Repository Data source Network Disk DB Memory Undabot
113. Network implementation public class TimeLineDataSourceNetwork implements TimeLineDataSource {
 
 private final TwitterAPI twitterAPI;
 private final TimelineResponseMapper mapper;
 
 public TimeLineDataSourceNetwork(TwitterAPI twitterAPI, TimelineResponseMapper mapper) {
 this.twitterAPI = twitterAPI;
 this.mapper = mapper;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return twitterAPI
 .getTimeline()
 .retryWhen(new RetryWithDelay(3, 500))
 .map(timelineResponseResult -> mapper.toTimeline(timelineResponseResult.response()));
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
114. Network implementation public class TimeLineDataSourceNetwork implements TimeLineDataSource {
 
 private final TwitterAPI twitterAPI;
 private final TimelineResponseMapper mapper;
 
 public TimeLineDataSourceNetwork(TwitterAPI twitterAPI, TimelineResponseMapper mapper) {
 this.twitterAPI = twitterAPI;
 this.mapper = mapper;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return twitterAPI
 .getTimeline()
 .retryWhen(new RetryWithDelay(3, 500))
 .map(timelineResponseResult -> mapper.toTimeline(timelineResponseResult.response()));
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
115. Network implementation public class TimeLineDataSourceNetwork implements TimeLineDataSource {
 
 private final TwitterAPI twitterAPI;
 private final TimelineResponseMapper mapper;
 
 public TimeLineDataSourceNetwork(TwitterAPI twitterAPI, TimelineResponseMapper mapper) {
 this.twitterAPI = twitterAPI;
 this.mapper = mapper;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return twitterAPI
 .getTimeline()
 .retryWhen(new RetryWithDelay(3, 500))
 .map(timelineResponseResult -> mapper.toTimeline(timelineResponseResult.response()));
 }
 
 /* Other methods/implementations */
 } public class TimeLineDataSourceNetwork implements TimeLineDataSource {
 
 private final TwitterAPI twitterAPI;
 private final TimelineResponseMapper mapper;
 
 public TimeLineDataSourceNetwork(TwitterAPI twitterAPI, TimelineResponseMapper mapper) {
 this.twitterAPI = twitterAPI;
 this.mapper = mapper;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return twitterAPI
 .getTimeline()
 .retryWhen(new RetryWithDelay(3, 500))
 .map(timelineResponseResult -> mapper.toTimeline(timelineResponseResult.response()));
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
116. Network implementation public interface TwitterAPI {
 
 @GET("statuses/home_timeline")
 Observable<Response<TimelineResponse>> getTimeline();
 
 /* Other APIs */
 } public class TimeLineDataSourceNetwork implements TimeLineDataSource {
 
 private final TwitterAPI twitterAPI;
 private final TimelineResponseMapper mapper;
 
 public TimeLineDataSourceNetwork(TwitterAPI twitterAPI, TimelineResponseMapper mapper) {
 this.twitterAPI = twitterAPI;
 this.mapper = mapper;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return twitterAPI
 .getTimeline()
 .retryWhen(new RetryWithDelay(3, 500))
 .map(timelineResponseResult -> mapper.toTimeline(timelineResponseResult.response()));
 }
 
 /* Other methods/implementations */
 } public class TimeLineDataSourceNetwork implements TimeLineDataSource {
 
 private final TwitterAPI twitterAPI;
 private final TimelineResponseMapper mapper;
 
 public TimeLineDataSourceNetwork(TwitterAPI twitterAPI, TimelineResponseMapper mapper) {
 this.twitterAPI = twitterAPI;
 this.mapper = mapper;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return twitterAPI
 .getTimeline()
 .retryWhen(new RetryWithDelay(3, 500))
 .map(timelineResponseResult -> mapper.toTimeline(timelineResponseResult.response()));
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
117. Repository Data source Network Disk DB Memory Undabot
118. public class TimelineRepositoryImpl implements TimelineRepository {
 
 private final TimeLineDataSourceNetwork networkDataSource;
 private final TimeLineDataSourceDisk diskDataSource;
 private final TimeLineDataSourceMem memoryDataSource;
 
 @Inject
 public TimelineRepositoryImpl(TimeLineDataSourceNetwork networkDataSource,
 TimeLineDataSourceDisk diskDataSource,
 TimeLineDataSourceMem memoryDataSource) {
 this.networkDataSource = networkDataSource;
 this.diskDataSource = diskDataSource;
 this.memoryDataSource = memoryDataSource;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return Observable
 .concat(memory(), diskWithSave(), networkWithSave())
 .first(timeline -> timeline != null);
 }
 
 private Observable<Timeline> memory() {
 return memoryDataSource.timeline();
 }
 
 private Observable<Timeline> diskWithSave() {
 return diskDataSource
 .timeline()
 .doOnNext(memoryDataSource::persist); // Save data to memory
 }
 
 private Observable<Timeline> networkWithSave() {
 return networkDataSource.timeline()
 .doOnNext(timeline -> {
 diskDataSource.persist(timeline); // Save data to disk
 memoryDataSource.persist(timeline); // Save data to memory
 });
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
119. public class TimelineRepositoryImpl implements TimelineRepository {
 
 private final TimeLineDataSourceNetwork networkDataSource;
 private final TimeLineDataSourceDisk diskDataSource;
 private final TimeLineDataSourceMem memoryDataSource;
 
 @Inject
 public TimelineRepositoryImpl(TimeLineDataSourceNetwork networkDataSource,
 TimeLineDataSourceDisk diskDataSource,
 TimeLineDataSourceMem memoryDataSource) {
 this.networkDataSource = networkDataSource;
 this.diskDataSource = diskDataSource;
 this.memoryDataSource = memoryDataSource;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return Observable
 .concat(memory(), diskWithSave(), networkWithSave())
 .first(timeline -> timeline != null);
 }
 
 private Observable<Timeline> memory() {
 return memoryDataSource.timeline();
 }
 
 private Observable<Timeline> diskWithSave() {
 return diskDataSource
 .timeline()
 .doOnNext(memoryDataSource::persist); // Save data to memory
 }
 
 private Observable<Timeline> networkWithSave() {
 return networkDataSource.timeline()
 .doOnNext(timeline -> {
 diskDataSource.persist(timeline); // Save data to disk
 memoryDataSource.persist(timeline); // Save data to memory
 });
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
120. public class TimelineRepositoryImpl implements TimelineRepository {
 
 private final TimeLineDataSourceNetwork networkDataSource;
 private final TimeLineDataSourceDisk diskDataSource;
 private final TimeLineDataSourceMem memoryDataSource;
 
 @Inject
 public TimelineRepositoryImpl(TimeLineDataSourceNetwork networkDataSource,
 TimeLineDataSourceDisk diskDataSource,
 TimeLineDataSourceMem memoryDataSource) {
 this.networkDataSource = networkDataSource;
 this.diskDataSource = diskDataSource;
 this.memoryDataSource = memoryDataSource;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return Observable
 .concat(memory(), diskWithSave(), networkWithSave())
 .first(timeline -> timeline != null);
 }
 
 private Observable<Timeline> memory() {
 return memoryDataSource.timeline();
 }
 
 private Observable<Timeline> diskWithSave() {
 return diskDataSource
 .timeline()
 .doOnNext(memoryDataSource::persist); // Save data to memory
 }
 
 private Observable<Timeline> networkWithSave() {
 return networkDataSource.timeline()
 .doOnNext(timeline -> {
 diskDataSource.persist(timeline); // Save data to disk
 memoryDataSource.persist(timeline); // Save data to memory
 });
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
121. public class TimelineRepositoryImpl implements TimelineRepository {
 
 private final TimeLineDataSourceNetwork networkDataSource;
 private final TimeLineDataSourceDisk diskDataSource;
 private final TimeLineDataSourceMem memoryDataSource;
 
 @Inject
 public TimelineRepositoryImpl(TimeLineDataSourceNetwork networkDataSource,
 TimeLineDataSourceDisk diskDataSource,
 TimeLineDataSourceMem memoryDataSource) {
 this.networkDataSource = networkDataSource;
 this.diskDataSource = diskDataSource;
 this.memoryDataSource = memoryDataSource;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return Observable
 .concat(memory(), diskWithSave(), networkWithSave())
 .first(timeline -> timeline != null);
 }
 
 private Observable<Timeline> memory() {
 return memoryDataSource.timeline();
 }
 
 private Observable<Timeline> diskWithSave() {
 return diskDataSource
 .timeline()
 .doOnNext(memoryDataSource::persist); // Save data to memory
 }
 
 private Observable<Timeline> networkWithSave() {
 return networkDataSource.timeline()
 .doOnNext(timeline -> {
 diskDataSource.persist(timeline); // Save data to disk
 memoryDataSource.persist(timeline); // Save data to memory
 });
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
122. public class TimelineRepositoryImpl implements TimelineRepository {
 
 private final TimeLineDataSourceNetwork networkDataSource;
 private final TimeLineDataSourceDisk diskDataSource;
 private final TimeLineDataSourceMem memoryDataSource;
 
 @Inject
 public TimelineRepositoryImpl(TimeLineDataSourceNetwork networkDataSource,
 TimeLineDataSourceDisk diskDataSource,
 TimeLineDataSourceMem memoryDataSource) {
 this.networkDataSource = networkDataSource;
 this.diskDataSource = diskDataSource;
 this.memoryDataSource = memoryDataSource;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return Observable
 .concat(memory(), diskWithSave(), networkWithSave())
 .first(timeline -> timeline != null);
 }
 
 private Observable<Timeline> memory() {
 return memoryDataSource.timeline();
 }
 
 private Observable<Timeline> diskWithSave() {
 return diskDataSource
 .timeline()
 .doOnNext(memoryDataSource::persist); // Save data to memory
 }
 
 private Observable<Timeline> networkWithSave() {
 return networkDataSource.timeline()
 .doOnNext(timeline -> {
 diskDataSource.persist(timeline); // Save data to disk
 memoryDataSource.persist(timeline); // Save data to memory
 });
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
123. public class TimelineRepositoryImpl implements TimelineRepository {
 
 private final TimeLineDataSourceNetwork networkDataSource;
 private final TimeLineDataSourceDisk diskDataSource;
 private final TimeLineDataSourceMem memoryDataSource;
 
 @Inject
 public TimelineRepositoryImpl(TimeLineDataSourceNetwork networkDataSource,
 TimeLineDataSourceDisk diskDataSource,
 TimeLineDataSourceMem memoryDataSource) {
 this.networkDataSource = networkDataSource;
 this.diskDataSource = diskDataSource;
 this.memoryDataSource = memoryDataSource;
 }
 
 @Override
 public Observable<Timeline> getTimeline() {
 return Observable
 .concat(memory(), diskWithSave(), networkWithSave())
 .first(timeline -> timeline != null);
 }
 
 private Observable<Timeline> memory() {
 return memoryDataSource.timeline();
 }
 
 private Observable<Timeline> diskWithSave() {
 return diskDataSource
 .timeline()
 .doOnNext(memoryDataSource::persist); // Save data to memory
 }
 
 private Observable<Timeline> networkWithSave() {
 return networkDataSource.timeline()
 .doOnNext(timeline -> {
 diskDataSource.persist(timeline); // Save data to disk
 memoryDataSource.persist(timeline); // Save data to memory
 });
 }
 
 /* Other methods/implementations */
 } Repository Data source Network Disk DB Memory Undabot
124. Data mapping Undabot
125. Data mapping public class Tweet {
 
 private long id;
 private String author;
 private String content;
 private String createdAt;
 private boolean favourited;
 private int retweetCount;
 
 
 /* Constructors, getters, setters, methods... */ } Undabot
126. Data mapping public class Tweet {
 
 private long id;
 private String author;
 @SerializedName("text")
 private String content;
 @SerializedName(value = "created_at", alternate = {"created"})
 private String createdAt;
 private boolean favourited;
 @SerializedName("retweet_count")
 private int retweetCount;
 
 public Tweet() {
 }
 
 
 /* Constructors, getters, setters, methods... */
 } Undabot
127. Data mapping @Table(database = TwitterDatabse.class)
 public class Tweet extends BaseModel {
 
 @PrimaryKey
 private long id;
 @Column
 private String author;
 @Column
 @SerializedName("text")
 private String content;
 @Column
 @SerializedName(value = "created_at", alternate = {"created"})
 private String createdAt;
 @Column
 private boolean favourited;
 @Column
 @SerializedName("retweet_count")
 private int retweetCount;
 
 public Tweet() {
 }
 
 
 /* Constructors, getters, setters, methods... */
 } Undabot
128. Data mapping Undabot
129. Data mapping Tweet ApiTweet DbTweet Undabot
130. Data mapping Tweet ApiTweet DbTweet ApiMapper DbMapper Undabot
131. Data mapping Tweet ApiTweet DbTweet Response model Response Mapper ApiMapper DbMapper Undabot
132. Data mapping Tweet ApiTweet DbTweet Response model Response Mapper ApiMapper DbMapper class TimelineResultMapper implements Func1<Result<TimelineResponse>, List<ApiTweet>> Undabot
133. Data mapping Tweet ApiTweet DbTweet Response model Response Mapper ApiMapper DbMapper class TimelineResultMapper implements Func1<Result<TimelineResponse>, List<ApiTweet>> .map(twitterResponseMapper); Undabot
134. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
135. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
136. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
137. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
138. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
139. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
140. Flow View Presenter UseCase Abstraction Model Business logic Repository Data source Network Disk DB Memory Undabot
141. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Native time pickers Continuous location Production payment Network ORMLite Undabot
142. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Continuous location Production payment Network ORMLite Undabot
143. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Better Pickers Continuous location Production payment Network ORMLite Undabot
144. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Better Pickers Picasso Continuous location Production payment Network ORMLite Undabot
145. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Better Pickers Picasso Continuous location Fixed location Production payment Network ORMLite Undabot
146. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Better Pickers Picasso Continuous location Fixed location Production payment Network ORMLite DBFlow Undabot
147. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Better Pickers Picasso Continuous location Fixed location Production payment Fake payment Network ORMLite DBFlow Undabot
148. Swappable implementations View Presenter UseCase Abstraction Model Business logic Repository Data source Location provider Image loader Glide Payment processor Pull to refresh Swipe refresh Native time pickers Better Pickers Picasso Continuous location Fixed location Production payment Fake payment Network Local mock ORMLite DBFlow Undabot
149. Packaging Undabot
150. Packaging presentation feature A
 feature B
 feature C domain data l a y e r s Package by layer Undabot
151. Packaging p a c k a g e s presentation feature A
 feature B
 feature C domain data l a y e r s Package by layer Undabot
152. Packaging p a c k a g e s presentation feature A
 feature B
 feature C domain data l a y e r s Package by layer feature A feature B feature C l a y e r s Package by feature Undabot
153. Packaging p a c k a g e s packages presentation feature A
 feature B
 feature C domain data l a y e r s Package by layer feature A feature B feature C l a y e r s Package by feature Undabot
154. Package by layer data (module)
 └───repository
 └───cache
 └───database
 └───api
 └───exception
 └───shared
 
 domain (module)
 └───model
 └───interactor
 └───executor
 └───abstraction
 └───shared
 
 presentation (module)
 └───presenter
 └───view
 └───navigation
 └───shared Undabot
155. Package by layer data (module)
 └───repository
 └───cache
 └───database
 └───api
 └───exception
 └───shared
 
 domain (module)
 └───model
 └───interactor
 └───executor
 └───abstraction
 └───shared
 
 presentation (module)
 └───presenter
 └───view
 └───navigation
 └───shared apply plugin: 'java' apply plugin: 'com.android.library'
 … compile project(':domain') apply plugin: ‘com.android.application' … compile project(':domain')
 compile project(':data') Undabot
156. Package by layer data (module)
 └───repository
 └───cache
 └───database
 └───api
 └───exception
 └───shared
 
 domain (module)
 └───model
 └───interactor
 └───executor
 └───abstraction
 └───shared
 
 presentation (module)
 └───presenter
 └───view
 └───navigation
 └───shared app (module)
 └───data
 └───repository
 └───cache
 └───database
 └───api
 └───exception
 └───shared
 └───domain
 └───model
 └───interactor
 └───executor
 └───abstraction
 └───shared
 └───presentation
 └───presenter
 └───view
 └───navigation
 └───shared Undabot
157. Package by layer data (module)
 └───repository
 └───cache
 └───database
 └───api
 └───exception
 └───shared
 
 domain (module)
 └───model
 └───interactor
 └───executor
 └───abstraction
 └───shared
 
 presentation (module)
 └───presenter
 └───view
 └───navigation
 └───shared app (module)
 └───data
 └───repository
 └───cache
 └───database
 └───api
 └───exception
 └───shared
 └───domain
 └───model
 └───interactor
 └───executor
 └───abstraction
 └───shared
 └───presentation
 └───presenter
 └───view
 └───navigation
 └───shared Undabot
158. Package by feature app
 └───core
 └───data
 └───utils
 └───timeline
 └───details
 └───gallery
 └───post
 └───profile
 └───notifications
 └───messaging
 └───metrics
 └───search
 └───settings Undabot
159. Package by feature app
 └───core
 └───data
 └───utils
 └───timeline
 └───details
 └───gallery
 └───post
 └───profile
 └───notifications
 └───messaging
 └───metrics
 └───search
 └───settings C C C C C C C C C C C profile gallery Undabot
160. THANK YOU Q & A @the_mmarko twitter.com/ MarkoMilosMM google.com/+ Marko Miloš, CTO @ Undabot