Introduction to the modification of the Clean Architecture that we use at Five Agency during our Android development

1. Intro to Five Architecture
29.09.2016@Five #IzSveSnagetomislav.homan@fiveminutes.eu
Or zero to clean….
Tomislav Homan, Five

2. Overview
● Earlier fails
● General Clean Architecture
● Clean Adjusted for Android
● Is it better?
● No code, just philosophy

3. Software Architecture
● “Intellectually graspable” abstraction of a complex system (wiki)
● (which helps us plan, design and construct software)

4. Software Architecture
● “Intellectually graspable” abstraction of a complex system (wiki)
● Multitude of stakeholders
● Separation of concerns - one reason to change
● Run away from the real world (Android, DB, Internet)
● Testability
● SRP + Testability + … = Maintainability, Scalability, etc...

5. The olden times - God activitypublic final class UsersActivity extends ListActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
new ListUsers().execute();
}
private final class ListUsers extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
// final SQLiteOpenHelper sqLiteOpenHelper = ...
// JsonObjectRequest jsObjRequest = new JsonObjectRequest
// (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
// MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
// showData(user);
return null;
}
}
}

6. The olden times - God activitypublic final class UsersActivity extends ListActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
new ListUsers().execute();
}
private final class ListUsers extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
// final SQLiteOpenHelper sqLiteOpenHelper = ...
// JsonObjectRequest jsObjRequest = new JsonObjectRequest
// (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
// MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
// showData(user);
return null;
}
}
}

7. The olden times - God activitypublic final class UsersActivity extends ListActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
new ListUsers().execute();
}
private final class ListUsers extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
// final SQLiteOpenHelper sqLiteOpenHelper = ...
// JsonObjectRequest jsObjRequest = new JsonObjectRequest
// (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
// MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
// showData(user);
return null;
}
}
}
NOT testable

8. The olden times - God activitypublic final class UsersActivity extends ListActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
new ListUsers().execute();
}
private final class ListUsers extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
// final SQLiteOpenHelper sqLiteOpenHelper = ...
// JsonObjectRequest jsObjRequest = new JsonObjectRequest
// (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
// MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
// showData(user);
return null;
}
}
}
NOT testable
Stakeholders?

9. The olden times - God activitypublic final class UsersActivity extends ListActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
new ListUsers().execute();
}
private final class ListUsers extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
// final SQLiteOpenHelper sqLiteOpenHelper = ...
// JsonObjectRequest jsObjRequest = new JsonObjectRequest
// (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
// MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
// showData(user);
return null;
}
}
}
NOT testable
Stakeholders?
SRP?

10. The olden times - God activitypublic final class UsersActivity extends ListActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
new ListUsers().execute();
}
private final class ListUsers extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... voids) {
// final SQLiteOpenHelper sqLiteOpenHelper = ...
// JsonObjectRequest jsObjRequest = new JsonObjectRequest
// (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
// MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
// showData(user);
return null;
}
}
}
NOT testable
Stakeholders?
SRP?
Mixed with
Android!

11. The olden times - MVP
● Better

12. The olden times - MVP
● Better

13. The olden times - MVP
● Better

14. The olden times - MVP
● Better
SRP

15. The olden times - MVP
● Better
SRP
Testable-ish

16. The olden times - MVP
● Better
SRP
Testable-ish
Stakeholders?

17. The olden times - MVP
● Better
SRP
Testable-ish
Mixed with
Android!
Stakeholders?

18. The olden times - MVP + Managers
● Sorta OK
Manager
this
Manager
that

19. The olden times - MVP + Managers
● Sorta OK
Manager
this
Manager
that
SRP - meh ok

20. The olden times - MVP + Managers
● Sorta OK
Manager
this
Manager
that
SRP - meh ok
Stakeholders

21. The olden times - MVP + Managers
● Sorta OK
Manager
this
Manager
that
SRP - meh ok
Stakeholders
Mixed with
Android!

22. The olden times - MVP + Managers
● Sorta OK
Manager
this
Manager
that
SRP - meh ok
Stakeholders
Mixed with
Android!
Testable-ish
Tend to be
HUGE!!!

23. The Clean Architecture

24. The Clean Architecture
Onion

25. The Clean Architecture
Ports and
Adapters

26. The Clean Architecture
● Dependency rule
● Abstraction
● Communication between layers

27. Dependency rule

28. Dependency rule

29. Dependency rule

30. Dependency rule

31. Dependency rule

32. Abstraction

33. Abstraction

34. Abstraction

35. All dependencies go to the
database
Core of the app
3 tier Clean
All dependencies go
to the business layer
Abstraction
Business is the core of
the app

36. Communication

37. Communication
I

38. Communication
O

39. Communication
I
O

40. Communication
I
O

41. Communication
I
O

42. Communication
I
O

43. Communication
I
O

44. Communication
I
O

45. Communication
I
Dependency
always pointing
inwards
O

46. Communication
I
Communication
can go both
inwards and
outwards
O

47. Adjusted for Android

48. Adjusted for Android

49. Entities

50. Entities
● AKA Domain Objects, Business Objects
● No interaction with the gritty details, no database, no Internet
● Simple business logic constrained to itself or its children
● Immutable
● No persistence methods (stay tuned)

51. Entities
Example: News app
● Category
● Article
● Commercial

52. Entities
Example: News app with user subscriptions
● Category
● Article
● Commercial
● User
● Subscription

53. Use Cases

54. Use Cases
● AKA Interactors, Business Services
● Small piece of business logic acting on one or more entities
● Must be able to describe its job by using common language (no details)
● Don’t skip use cases

55. Use Cases
Example: Transfer money to account use case
● Load two accounts
● Do some validation
● If OK transfer money
● Save the changes
Note the simple common language

56. Repositories

57. Repositories
● Perform CRUD operations on entities
● Additionally: filtering, aggregate operations, etc…
● Repository is abstract (output port)
● Concrete implementation in outer layers (DAO, API, Cache, Combination)
● Can handle entity’s whole object tree

58. Presenters

59. Presenters
● Always have accompanied view
● Gather info and send them to view
● Don’t know concrete view implementation (view as output port)
● But tied to its lifecycle
● User input delegated to presenters
● Usually map entities to viewmodels

60. Presenters
Example: Screen showing details of an account - abstraction
View
● onTransactionButtonClicked
● onUserItemSelected
● setUserListPanelVisible
● setGenderBoxEnabled
Presenter
● doTransaction
● selectUser
● showUsers
● activateGenderView

61. Device

62. Device
● Gritty Android stuff
● NOT Db, Internet or UI - separate component
● Sensors, alarms, notifications, players, etc…
● Define wrappers around Android objects in Device component
● Define interface that wrapper will be implementing in domain component
to serve as an output port

63. Device
LocationManager
NotificationManager
AlarmManager
MediaPlayer
LocationManagerWrapper
NotificationManagerWrapper
AlarmManagerWrapper
MediaPlayerWrapper
Locations
Notifications
Alarms
Player
Use case 1
Use case 2
Use case 3
Use case 4
Device Domain

64. DB & API

65. DB & API
● Also access to the real world
● This time real world are a database and the Internet
● Classes such as SQLiteOpenHelper, DbModels, DAOs, Retrofit interfaces
and services, API models, JSON parsers…
● If you are using database only, DAO can implement a repository
● Inner layers use entities, so you should also return entities -> mappers

66. UI

67. UI
● Android classes used for interacting with user via display
● Fragments, Activities, Adapters, Views, Animations, etc…
● Display logic only

68. Modules

69. Modules
Domain

70. Modules
Device

71. Modules
Data

72. Modules
UI (app)

73. Modules
MVP still here

74. Is it better?

75. Is it better?
Manager
this
Manager
that
SRP - meh ok
Stakeholders
Mixed with
Android!
Testable-ish

76. Is it better?
Manager
this
Manager
that

77. Is it better?

78. Is it better?

79. Is it better?
Use
case 1
Use
case 2
Use
case 3
...

80. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository

81. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...

82. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
UI

83. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
UI
Domain

84. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
UI
DataDomain

85. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
UI
Device
DataDomain

86. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
UI
Device
Outer worldDataDomain

87. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
UI
Device
Outer worldDataDomain
SRP

88. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP

89. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP

90. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Not mixed with
Android!

91. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Not mixed with
Android!

92. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Not mixed with
Android!

93. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!

94. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!

95. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!
UI designer cares about this

96. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!
UI designer cares about this
UX designer cares about this

97. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!
UI designer cares about this
UX designer cares about this
BA, QA, PM care about this

98. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!
UI designer cares about this
UX designer cares about this
BA, QA, PM care about this
Nobody cares about this

99. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!
UI designer cares about this
UX designer cares about this
BA, QA, PM care about this
Backend guys care about
this
Nobody cares about this

100. Is it better?
Use
case 1
Use
case 2
Use
case 3
...
Repository
Location
Notifications
...
SRP
Testable
Not mixed with
Android!Stakeholders
are satisfied

102. http://five.agency/about/careers/