Reactive Workflows

Our MVP app is too big. Introducing the Workflow pattern to try to get it back under control. Plays well with Rx, minimizes platform-specific dependencies. Woo hoo!

https://droidcon-server.herokuapp.com/showSession/103028
https://www.youtube.com/watch?v=KjoMnsc2lPo

2. reacting to code sprawl Reactive Workflows Ray Ryan
3. Key-based MVP the legacy
4. Key-based MVP Key flow.set(Key)
5. Key-based MVP Key View
6. Key-based MVP Key Presenter View
7. Key-based MVP Key Presenter View Model Model Model
8. Key-based MVP CartScreen Cart Presenter CartView Item Library Cart
9. Key-based MVP CartScreen Cart Presenter CartView Item Library Cart flow.set(ChargeScreen)
10. ChargeScreen Key-based MVP CartScreen Cart Presenter CartView Item Library Cart
11. Key-based MVP ChargeScreen CartScreen
12. Key-based MVP Charge Presenter Charge View Cart Bill Card Reader ChargeScreen CartScreen
13. Key-based MVP Charge Presenter Charge View Cart Bill Card Reader ChargeScreen CartScreen
14. Key-based MVP Charge Presenter Charge View Cart Bill Card Reader ChargeScreen CartScreen
15. Nav logic sprawl ChargeScreen CartScreen
16. Nav logic sprawl ChargeScreen CartScreen TipScreen
17. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen
18. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen
19. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen ReceiptScreen
20. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen ReceiptScreen
21. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen ReceiptScreen
22. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen ReceiptScreen
23. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen ReceiptScreen Payment Runner
24. Nav logic sprawl ChargeScreen CartScreen TipScreen SignatureScreen ReceiptScreen Payment Runner SettingsScreen
25. Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner
26. Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner cardSwiped()
27. Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner setCardInfo() cardSwiped()
28. Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner setCardInfo() cardSwiped() next()
29. Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner setCardInfo() cardSwiped() show tip screen? next()
30. show signature screen? Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner setCardInfo() cardSwiped() show tip screen? next()
31. show signature screen? Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner setCardInfo() finishPayment() cardSwiped() show tip screen? next()
32. show signature screen? Nav & biz logic entangled Charge Presenter Bill Card Reader ChargeScreen Payment Runner setCardInfo() finishPayment() cardSwiped() show tip screen? next()
33. AddCustomer Runner Awkward reuse Cart Presenter CartScreen Cart
34. AddCustomer Runner Awkward reuse Cart Presenter start() CartScreen Cart
35. PickCustomerScreen AddCustomer Runner Awkward reuse Cart Presenter start() CartScreen Cart
36. AddCustomer Runner Awkward reuse Pick Customer Presenter PickCustomerScreen CartScreen Cart
37. AddCustomer Runner Awkward reuse Pick Customer Presenter PickCustomerScreen CartScreen Cart setCustomer() + Customer
38. AddCustomer Runner Awkward reuse Receipt Presenter ReceiptScreen Receipt
39. AddCustomer Runner Awkward reuse Receipt Presenter start() ReceiptScreen Receipt flow.set(PickCustomerScreen)
40. AddCustomer Runner Awkward reuse Receipt Presenter start() ReceiptScreen Receipt PickCustomerScreen
41. AddCustomer Runner Awkward reuse Pick Customer Presenter PickCustomerScreen ReceiptScreen
42. AddCustomer Runner Awkward reuse Pick Customer Presenter PickCustomerScreen ReceiptScreen Cart Receipt ?
43. AddCustomer Runner Awkward reuse Pick Customer Presenter PickCustomerScreen ReceiptScreen ? + Customer
44. AddCustomer Runner Awkward reuse Pick Customer Presenter PickCustomerScreen ReceiptScreen ? + Customer
45. Still, pretty good enough Nearly two hundred contributors Around three hundred screens Ships every two weeks
46. Good enough don’t scale four years later
47. Good enough don’t scale 12 minute clean build 2-4 minute rebuild Spaghetti of the commons
48. iOS even worse ViewControllers full of business logic WWAD syndrome • Static singletons • CoreData all the things • Undiffable XIB, Storyboard files
49. Learned helplessness Each platform > 750,000 LOC Remember, THREE HUNDRED SCREENS Nearly half just in payment flow Grassroots heroics no longer practical
50. Learned helplessness Each platform > 750,000 LOC Remember, THREE HUNDRED SCREENS Nearly half just in payment flow Grassroots heroics no longer practical
51. Reclaiming the commons we bring glad tidings from the future
52. Reclaiming the commons Make fixing things someone’s job Make success possible • Define the problems • Describe utopia • Declare and execute two year plan Define the problems
53. Define the problems Edit, compile, debug loop is too slow The code is too complex Dependencies are too interconnected
54. Define the problems Edit, compile, debug loop is too slow The code is too complex Dependencies are too interconnected Modularize: small code blocks build faster Modularize: big features from simpler parts Modularize: dependencies are a DAG
55. Describe Utopia
56. Describe Utopia
57. Utopia's core principals Immutability is assumed Be reactive: push, don’t pull Natural separation of UI and business concerns Uniformity of API across platforms Uniformity Utopia
58. “Uniformity?” Code sharing? Maybe Writing is the easy part, maintenance is forever Shared code is foreign code Have you considered… • Shared tests • Shared API definitions (protocol buffers) Uniformity
59. “Uniformity?” Code sharing? Maybe Writing is the easy part, maintenance is forever Shared code is foreign code Have you considered… • Shared tests • Shared API definitions (protocol buffers) Uniformity
60. Workflows and Bricks Brick
61. Workflows and Bricks Bricks Business model i/o Brick
62. Workflows and Bricks Bricks Workflows Business model i/o App logic UI modeling Brick
63. Workflows and Bricks Bricks Workflows Container Business model i/o App logic UI modeling Rendering UI event handling View Factory Brick
64. Workflows and Bricks Bricks Workflows Container Business model i/o App logic UI modeling Rendering UI event handling Platform neutral* View code View Factory Brick
65. “Brick” rhymes with “schmego” Brick
66. “Brick” rhymes with “schmego”
67. “Brick” rhymes with “schmego”
68. “Brick” rhymes with “schmego” setFoo(FooValue f) Observable<BarValue> bar();
69. “Brick” rhymes with “schmego” setFoo(FooValue f) Observable<BarValue> bar();
70. “Brick” rhymes with “schmego” BarValue getBar(); setFoo(FooValue f) Observable<BarValue> bar();
71. “Brick” rhymes with “schmego” BarValue getBar(); setFoo(FooValue f) Observable<BarValue> bar();
72. “Brick” rhymes with “schmego” BarValue getBar(); setFoo(FooValue f) Observable<BarValue> bar(); SqlBrite / SqlDelight *RxPreferences, *Rooms Retrofit
73. Build big bricks from small bricks
74. Build big bricks from small bricks
75. Build big bricks from small bricks
76. Build big bricks from small bricks j2Objc JavaScript
77. enum class StateOfPlay { PLAYING, VICTORY, DRAW }
78. enum class StateOfPlay { PLAYING, VICTORY, DRAW } enum class MARK { EMPTY, X, O }
79. enum class StateOfPlay { PLAYING, VICTORY, DRAW } enum class MARK { EMPTY, X, O } data class Player( val id: String, val name: String )
80. data class GameState( val id: String, val playerX: Player, val playerO: Player, val stateOfPlay: StateOfPlay, val grid: List<List<MARK>>, val activePlayerId: String ) enum class StateOfPlay { PLAYING, VICTORY, DRAW } enum class MARK { EMPTY, X, O } data class Player( val id: String, val name: String )
81. class GameRunner { fun newGame(xPlayerName: String, oPlayerName: String) {} fun restoreGame(clientId: String) {} fun takeSquare(row: Int, col: Int) {} fun end() {} fun gameState(): Observable<GameState> {} }
82. class GameRunner { /** @throws AssertionError if not called from main thread */ fun newGame(xPlayerName: String, oPlayerName: String) {} /** @throws AssertionError if not called from main thread */ fun restoreGame(clientId: String) {} /** @throws AssertionError if not called from main thread */ fun takeSquare(row: Int, col: Int) {} /** @throws AssertionError if not called from main thread */ fun end() {} fun gameState(): Observable<GameState> {} } fun newGame(xPlayerName: String, oPlayerName: String) fun restoreGame(clientId: String) class GameRunner {
83. class GameRunner { /** @throws AssertionError if not called from main thread */ fun newGame(xPlayerName: String, oPlayerName: String) {} /** @throws AssertionError if not called from main thread */ fun restoreGame(clientId: String) {} /** @throws AssertionError if not called from main thread */ fun takeSquare(row: Int, col: Int) {} /** @throws AssertionError if not called from main thread */ fun end() {} fun gameState(): Observable<GameState> {} } fun newGame(xPlayerName: String, oPlayerName: String) fun restoreGame(clientId: String) class GameRunner { observeOn(mainThread()) speakerdeck.com/rjrjr/ where-the-reactive-rubber-meets-the-road
84. class GameRunner { /** @throws AssertionError if not called from main thread */ fun newGame(xPlayerName: String, oPlayerName: String) {} /** @throws AssertionError if not called from main thread */ fun restoreGame(clientId: String) {} /** @throws AssertionError if not called from main thread */ fun takeSquare(row: Int, col: Int) {} /** @throws AssertionError if not called from main thread */ fun end() {} fun gameState(): Observable<GameState> {} } fun newGame(xPlayerName: String, oPlayerName: String) fun restoreGame(clientId: String) class GameRunner {
85. class GameRunner {
86. class GameRunner { sealed class Command { data class NewGame(val xPlayer: String, val yPlayer: String): Command() data class RestoreGame(val id: String): Command() data class TakeSquare(val row: Int, val col: Int): Command() object End: Command() } fun asTransformer(): Observable.Transformer<Command, GameState> { } }
87. class GameRunner { sealed class Command { data class NewGame(val xPlayer: String, val yPlayer: String): Command() data class RestoreGame(val id: String): Command() data class TakeSquare(val row: Int, val col: Int): Command() object End: Command() } fun asTransformer(): Observable.Transformer<Command, GameState> { } } search for: Dan Lew transformer
88. Workflow through the brickyard
89. Remember these things? Charge Presenter Bill ChargeScreen Payment Runner setCardInfo() finishPayment() next() flow.set(TipScreen) Charge View
90. Remember these things? Charge Presenter Bill ChargeScreen Payment Runner setCardInfo() finishPayment() next() flow.set(TipScreen) Charge View
91. Remember these things? Charge Presenter Bill ChargeScreen Payment Runner setCardInfo() finishPayment() next() flow.set(TipScreen) Charge View
92. Remember these things? Charge Presenter Bill ChargeScreen Payment Runner setCardInfo() finishPayment() next() flow.set(TipScreen) Charge View
93. Presenter Runner + = Workflow<I, R>
94. Workflow as Presenter + = Workflow<I, R> start(I input) Maybe<R> result() abort() pipeline
95. Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() ui driver Observable<WorkflowScreen> screen()
96. Rhymes with “view model” /** Allows interaction with a [Workflow] in a particular state. */ abstract class WorkflowScreen<D, out E> protected constructor( /** Uniquely identifies this screen. */ val key: String, /** Stream of data to render this screen. */ val screenData: Observable<D>, /** Callback methods (click handlers, etc.) handled by this screen. */ val eventHandler: E )
97. LoginScreen AuthorizingScreen SecondFactorScreen
98. class LoginScreen( errorMessage: Observable<String>, eventHandler: Events ) : WorkflowScreen<String, Events>(KEY, errorMessage, eventSink) { companion object { val KEY = LoginScreen::class.name } interface Events { fun onLogin(event: SubmitLogin) } data class SubmitLogin( val email: String, val password: String ) }
99. class LoginScreen( errorMessage: Observable<String>, eventHandler: Events ) : WorkflowScreen<String, Events>(KEY, errorMessage, eventSink) { companion object { val KEY = LoginScreen::class.name } interface Events { fun onLogin(event: SubmitLogin) } data class SubmitLogin( val email: String, val password: String ) }
100. class LoginScreen( errorMessage: Observable<String>, eventHandler: Events ) : WorkflowScreen<String, Events>(KEY, errorMessage, eventSink) { companion object { val KEY = LoginScreen::class.name } interface Events { fun onLogin(event: SubmitLogin) } data class SubmitLogin( val email: String, val password: String ) }
101. class LoginScreen( errorMessage: Observable<String>, eventHandler: Events ) : WorkflowScreen<String, Events>(KEY, errorMessage, eventSink) { companion object { val KEY = LoginScreen::class.name } interface Events { fun onLogin(event: SubmitLogin) } data class SubmitLogin( val email: String, val password: String ) }
102. class ConfirmChargeCardOnFileScreen( screenData: Observable<ScreenData>, eventHandler: Events ) : WorkflowScreen<ScreenData, Events>(KEY, screenData, eventHandler) { companion object { val KEY = ConfirmChargeCardOnFileScreen::class.name } data class ScreenData( val amountDue: Money, val customerName: String, val cardNameAndNumber: String, val instrumentIndex: Int) interface Events { fun doNotChargeCardOnFile() fun chargeCardOnFile(tenderedAmount: Money, instrumentIndex: Int) }
103. Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() view model source Observable<WorkflowScreen> screen()
104. Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() view model source Observable<WorkflowScreen> screen() ✔
105. View Factory Container Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() view model source Observable<WorkflowScreen> screen() RootView ✔
106. class AuthViewFactory : AbstractViewFactory(asList( bindLayout(LoginScreen.KEY, R.layout.login) { screen -> LoginCoordinator(screen as LoginScreen) }, bindLayout(AuthorizingScreen.KEY, R.layout.authorizing) { screen -> AuthorizingCoordinator(screen as AuthorizingScreen) }, bindLayout(SecondFactorScreen.KEY, R.layout.second_factor) { screen -> SecondFactorCoordinator(screen as SecondFactorScreen) } ))
107. class LoginCoordinator(private val screen: LoginScreen) : Coordinator() { private var subscription: Subscription = Subscriptions.unsubscribed() override fun attach(view: View) {
108. class LoginCoordinator(private val screen: LoginScreen) : Coordinator() { private var subscription: Subscription = Subscriptions.unsubscribed() override fun attach(view: View) { val error = view.findViewById<View>(R.id.login_error_message) as TextView val email = view.findViewById<View>(R.id.login_email) as EditText val password = view.findViewById<View>(R.id.login_password) as EditText val button = view.findViewById<View>(R.id.login_button) as Button
109. class LoginCoordinator(private val screen: LoginScreen) : Coordinator() { private var subscription: Subscription = Subscriptions.unsubscribed() override fun attach(view: View) { val error = view.findViewById<View>(R.id.login_error_message) as TextView val email = view.findViewById<View>(R.id.login_email) as EditText val password = view.findViewById<View>(R.id.login_password) as EditText val button = view.findViewById<View>(R.id.login_button) as Button button.setOnClickListener { _ -> val event = SubmitLogin(email.text.toString(), password.text.toString()) screen.eventHandler.login(event) }
110. class LoginCoordinator(private val screen: LoginScreen) : Coordinator() { private var subscription: Subscription = Subscriptions.unsubscribed() override fun attach(view: View) { val error = view.findViewById<View>(R.id.login_error_message) as TextView val email = view.findViewById<View>(R.id.login_email) as EditText val password = view.findViewById<View>(R.id.login_password) as EditText val button = view.findViewById<View>(R.id.login_button) as Button button.setOnClickListener { _ -> val event = SubmitLogin(email.text.toString(), password.text.toString()) screen.eventHandler.login(event) } subscription = screen.screenData.subscribe { error.text = it } }
111. class LoginCoordinator(private val screen: LoginScreen) : Coordinator() { private var subscription: Subscription = Subscriptions.unsubscribed() override fun attach(view: View) { … } override fun detach(view: View?) { subscription.unsubscribe() }
112. class LoginCoordinator(private val screen: LoginScreen) : Coordinator() { private var subscription: Subscription = Subscriptions.unsubscribed() override fun attach(view: View) { … } override fun detach(view: View?) { subscription.unsubscribe() } search for: square coordinators
113. Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() state machine Container Observable<WorkflowScreen> screen() View Factory RootView ✔
114. Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() state machine Container Observable<WorkflowScreen> screen() View Factory RootView ✔ ✔ + Square Coordinators
115. Workflow as = Workflow<I, R> start(I input) Maybe<R> result() abort() state machine Container Observable<WorkflowScreen> screen() View Factory RootView ✔ ✔ + Square Coordinators
116. class AuthWorkflow(): Workflow<Unit, String>
117. class AuthWorkflow(): Workflow<Unit, String>, LoginScreen.Events, SecondFactorScreen.Events
118. class AuthWorkflow(): Workflow<Unit, String>, LoginScreen.Events, SecondFactorScreen.Events { private val currentScreen = BehaviorSubject.create<String>()
119. class AuthWorkflow(): Workflow<Unit, String>, LoginScreen.Events, SecondFactorScreen.Events { private val currentScreen = BehaviorSubject.create<String>() private val loginMessage = BehaviorSubject.create("") private val authorizingMessage = BehaviorSubject.create<String>() private val secondFactorMessage = BehaviorSubject.create<String>()
120. class AuthWorkflow(): Workflow<Unit, String>, LoginScreen.Events, SecondFactorScreen.Events { private val currentScreen = BehaviorSubject.create<String>() private val loginMessage = BehaviorSubject.create("") private val authorizingMessage = BehaviorSubject.create<String>() private val secondFactorMessage = BehaviorSubject.create<String>() override fun screen(): Observable<WorkflowScreen<*,*> = currentScreen.map { it -> when (it) { LoginScreen.KEY -> LoginScreen(loginMessage, this) AuthorizingScreen.KEY -> AuthorizingScreen(authorizingMessage) SecondFactorScreen.KEY -> SecondFactorScreen(secondFactorMessage, this) else -> throw IllegalArgumentException("Unknown key " + it) } }
121. class AuthWorkflow(): Workflow<Unit, String>, LoginScreen.Events, SecondFactorScreen.Events { …
122. class AuthWorkflow(): Workflow<Unit, String>, LoginScreen.Events, SecondFactorScreen.Events { … override fun onLogin(event: LoginScreen.SubmitLogin) { stateMachine.onEvent(event) } override fun onSecondFactor(event: SecondFactorScreen.SecondFactor) { stateMachine.onEvent(event) }
123. internal enum class State { LOGIN_PROMPT, AUTHORIZING, SECOND_FACTOR_PROMPT, DONE }
124. internal enum class State { LOGIN_PROMPT, AUTHORIZING, SECOND_FACTOR_PROMPT, DONE } init { stateMachine = FiniteStateMachine( onEntry(AUTHORIZING) { currentScreen.onNext(AuthorizingScreen.KEY) }, onEntry(SECOND_FACTOR_PROMPT) { currentScreen.onNext(SecondFactorScreen.KEY) },
125. internal enum class State { LOGIN_PROMPT, AUTHORIZING, SECOND_FACTOR_PROMPT, DONE } init { stateMachine = FiniteStateMachine( …
126. internal enum class State { LOGIN_PROMPT, AUTHORIZING, SECOND_FACTOR_PROMPT, DONE } init { stateMachine = FiniteStateMachine( … transition(LOGIN_PROMPT, SubmitLogin::class, AUTHORIZING) .doAction { doLogin(it) }, transition(AUTHORIZING, AuthResponse::class, LOGIN_PROMPT) .onlyIf { isLoginFailure(it) } .doAction { response -> val errorMessage = response.errorMessage loginMessage.onNext(errorMessage) },
127. internal enum class State { LOGIN_PROMPT, AUTHORIZING, SECOND_FACTOR_PROMPT, DONE } init { stateMachine = FiniteStateMachine( … transition(LOGIN_PROMPT, SubmitLogin::class, AUTHORIZING) .doAction { doLogin(it) }, transition(AUTHORIZING, AuthResponse::class, LOGIN_PROMPT) .onlyIf { isLoginFailure(it) } .doAction { response -> val errorMessage = response.errorMessage loginMessage.onNext(errorMessage) }, search for: Andy Matuschak states
128. NewGameScreen GamePlayScreen GameOverScreen ConfirmQuitScreen
129. class TicTacToeViewFactory private constructor() : AbstractViewFactory(asList( bindLayout(NewGameScreen.KEY, layout.new_game_layout ) { screen -> NewGameCoordinator(screen as NewGameScreen) }, bindLayout(GamePlayScreen.KEY, layout.game_play_layout ) { screen -> GamePlayCoordinator(screen as GamePlayScreen) }, bindLayout(GameOverScreen.KEY, layout.game_play_layout ) { screen -> GameOverCoordinator(screen as GameOverScreen) }, bindDialog(ConfirmQuitScreen.KEY ) { screen -> ConfirmQuitDialogFactory(screen as ConfirmQuitScreen) } ))
130. class TicTacToeViewFactory private constructor() : AbstractViewFactory(asList( bindLayout(NewGameScreen.KEY, layout.new_game_layout ) { screen -> NewGameCoordinator(screen as NewGameScreen) }, bindLayout(GamePlayScreen.KEY, layout.game_play_layout ) { screen -> GamePlayCoordinator(screen as GamePlayScreen) }, bindLayout(GameOverScreen.KEY, layout.game_play_layout ) { screen -> GameOverCoordinator(screen as GameOverScreen) }, bindDialog(ConfirmQuitScreen.KEY ) { screen -> ConfirmQuitDialogFactory(screen as ConfirmQuitScreen) } ))
131. class TicTacToeViewFactory private constructor() : AbstractViewFactory(asList( bindLayout(NewGameScreen.KEY, layout.new_game_layout ) { screen -> NewGameCoordinator(screen as NewGameScreen) }, bindLayout(GamePlayScreen.KEY, layout.game_play_layout ) { screen -> GamePlayCoordinator(screen as GamePlayScreen) }, bindLayout(GameOverScreen.KEY, layout.game_play_layout ) { screen -> GameOverCoordinator(screen as GameOverScreen) }, bindDialog(ConfirmQuitScreen.KEY ) { screen -> ConfirmQuitDialogFactory(screen as ConfirmQuitScreen) } ))
132. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>
133. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events {
134. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { private val gameStates: Observable<TicTacToeGameState> = gameRunner.gameState().startWith(NO_GAME)
135. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { private val gameStates: Observable<TicTacToeGameState> = gameRunner.gameState().startWith(NO_GAME) companion object { private val FAKE_ID = UUID.randomUUID().toString() private val NO_GAME = TicTacToeGameState.newGame(FAKE_ID, Player(FAKE_ID, "X"), Player(FAKE_ID, "O")) }
136. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { private val gameStates: Observable<TicTacToeGameState> = gameRunner.gameState().startWith(NO_GAME) …
137. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { private val gameStates: Observable<TicTacToeGameState> = gameRunner.gameState().startWith(NO_GAME) private val quitting = BehaviorSubject.create(false) …
138. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { private val gameStates: Observable<TicTacToeGameState> = gameRunner.gameState().startWith(NO_GAME) private val quitting = BehaviorSubject.create(false) private val screen = combineLatest(gameStates, quitting, { gameState, quitting -> update(gameState, quitting) }) .replay(1) override fun screen(): Observable<WorkflowScreen<*,*>> = screen …
139. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { …
140. class TicTacToeWorkflow( private val gameRunner: GameRunner ): Workflow<Unit, TicTacToeGameState>, NewGameScreen.Events, GamePlayScreen.Events, ConfirmQuitScreen.Events, GameOverScreen.Events { … private fun update(gameState: GameState, quitting: Boolean): WorkflowScreen<*,*> { if (quitting) return ConfirmQuitScreen(this) if (gameState == NO_GAME) NewGameScreen(this) return when (gameState.stateOfPlay) { PLAYING -> GamePlayScreen(gameStates, this) VICTORY, DRAW -> GameOverScreen(gameStates, this) } } …
141. RootView View Factory Container Workflow
142. RootView View Factory Container Workflow
143. RootView Key ScreenData Events WorkflowScreen View Factory Container Workflow
144. RootView Key ScreenData Events WorkflowScreen View Factory Container Workflow
145. RootView Key ScreenData Events WorkflowScreen View Factory Container Workflow
146. RootView View Factory Container Workflow
147. RootView Key ScreenData Events WorkflowScreen View Factory Container Workflow
148. RootView View Factory Container Workflow
149. Workflow You said these things compose
150. Workflow You said these things compose Auth Workflow Game Workflow
151. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
152. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
153. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
154. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
155. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
156. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
157. new CompositeWorkflow<>( // Start in the AuthWorkflow. When it finishes, kick off // a TicTacToe game. new WorkflowBinding<>(AuthWorkflow.class, () -> ignoreStartArg(authWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))), // When a TicTacToe game ends, start another one. new WorkflowBinding<>(TicTacToeWorkflow.class, () -> ignoreStartArg(ticTacToeWorkflowProvider.get()), (composite, result) -> composite.startWorkflow( forArg(TicTacToeWorkflow.class, (Unit) UNIT))) )
158. Master Status Detail1 Detail2 Detail3
159. Tactics
160. Step zero: make refactoring… …possible • Mock service layer • Robot-based UI tests (espresso, KIF) …tolerable • OkBuck for Android • CocoaPods for iOS
161. Divide first, conquer later
162. Always be writing PSAs Design docs (everyone, all the time) Policy docs (a few, mostly: “write a damn design doc”) How-to guides and sample code
163. Full disclosure Brick pattern established on both First j2Objc brick entering production Non-toy workflows in development on both Composite Workflow on Android Composite WorkflowScreen TBD
164. @rjrjr speakerdeck.com/rjrjr/where-the-reactive-rubber-meets-the-road Dan Lew transformer github.com/square/coordinators Andy Matuschak states (http://bfy.tw/E969) square.com/jobs