Tweet
Tweet

Slide 1

Slide 1 text

Benoît Quenaudon @oldergod Applying Rx Best Practices to your Architecture

Slide 2

Slide 2 text

Side-Effects Isolation

Slide 3

Slide 3 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k }i }z

Slide 4

Slide 4 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject@ .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) }i }z

Slide 5

Slide 5 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject@ .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) }i }z

Slide 6

Slide 6 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject@ .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) }i }z

Slide 7

Slide 7 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject@ .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i }z

Slide 8

Slide 8 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g }z

Slide 9

Slide 9 text

class ProfileView {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) }z

Slide 10

Slide 10 text

val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) }b }z

Slide 11

Slide 11 text

fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) appService.setName(newName) .subscribe { response -> when {e response.isValid -> nameSubject.onNext(response.name) response.isInvalid -> navigator.goTo(response.error) }d }c }b

Slide 12

Slide 12 text

fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) appService.setName(newName) .subscribe { response -> when {e response.isValid -> nameSubject.onNext(response.name) response.isInvalid -> navigator.goTo(response.error) }d }c }b

Slide 13

Slide 13 text

fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) appService.setName(newName) .subscribe { response -> when {e response.isValid -> nameSubject.onNext(response.name) response.isInvalid -> navigator.goTo(response.error) }d }c }b

Slide 14

Slide 14 text

fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) appService.setName(newName) .subscribe { response -> when {e response.isValid -> nameSubject.onNext(response.name) response.isInvalid -> navigator.goTo(response.error) }d }c }b

Slide 15

Slide 15 text

How about Side Effects?

Slide 16

Slide 16 text

fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) appService.setName(newName) .subscribe { response -> when {e response.isValid -> nameSubject.onNext(response.name) response.isInvalid -> navigator.goTo(response.error) }d }c }b

Slide 17

Slide 17 text

fun onStart() {k nameSubject .switchMap { name -> appService.profile() .map { profile -> profile.prefix } .map { profile -> if (name.isEmpty()) "" else "$prefix $name" } }j .subscribe(nameView::setText) // hint grows the view in width so hide it if unnecessary nameSubject .map { name -> if (name.isEmpty()) "Set your name" else "" } .subscribe(nameView::setHint) appService.profile().subscribe(this::populateProfile) }i fun populateProfile(profile: Profile) {h nameSubject.onNext(profile.name) // rendering other stuff }g fun onSetNameDialogResult(newName: String) = setName(newName) fun setName(newName: String) {f nameSubject.onNext(newName) appService.setName(newName) .subscribe { response -> when {e response.isValid -> nameSubject.onNext(response.name) response.isInvalid -> navigator.goTo(response.error) }d }c }b

Slide 18

Slide 18 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {t }i }t

Slide 19

Slide 19 text

sealed class Event { data class EditName(val newName: String) : Event() }

Slide 20

Slide 20 text

sealed class Result { data class ProfileResult(val profile: Profile) : Result() data class NameValid(val name: String) : Result() object NameInvalid : Result() }

Slide 21

Slide 21 text

data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName )a

Slide 22

Slide 22 text

data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName )a{ data class PrefixedName( val prefix: String, val name: String ) { fun compute(name:String): String = if (name.isEmpty()) "" else "$prefix $name" } }

Slide 23

Slide 23 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() fun onStart() {t }i }t

Slide 24

Slide 24 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> }i }t

Slide 25

Slide 25 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> .subscribe { viewModel -> }o }i }t

Slide 26

Slide 26 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 27

Slide 27 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> }g }h .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 28

Slide 28 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f }g }h .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 29

Slide 29 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 30

Slide 30 text

class ProfileViewRemix {a val navigator: Navigator val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 31

Slide 31 text

val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 32

Slide 32 text

val nameView: TextView val appService: AppService val nameSubject = BehaviorSubject.create() val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 33

Slide 33 text

val events = PublishSubject.create() fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i }t

Slide 34

Slide 34 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o

Slide 35

Slide 35 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y }t

Slide 36

Slide 36 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y }t

Slide 37

Slide 37 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y

Slide 38

Slide 38 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y

Slide 39

Slide 39 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y

Slide 40

Slide 40 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y

Slide 41

Slide 41 text

One Stream Many Options

Slide 42

Slide 42 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y

Slide 43

Slide 43 text

fun onStart() {t events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) } }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )k }l })p .subscribe { viewModel -> nameView.hint = if (viewModel.prefixedName.name.isEmpty()) "Set your name" else "" nameView.text = viewModel.prefixedName.compute() // rendering other stuff }o }i fun onSetNameDialogResult(newName: String) {u events.onNext(EditName(newName)) }y

Slide 44

Slide 44 text

events // Observable .subscribe { viewModel -> }o

Slide 45

Slide 45 text

events // Observable .subscribe { viewModel -> }o

Slide 46

Slide 46 text

Passing events to the Presenter

Slide 47

Slide 47 text

Option A Passing events to the Presenter

Slide 48

Slide 48 text

events .subscribe { viewModel -> }o class ProfilePresenter : Consumer { }z View Presenter

Slide 49

Slide 49 text

events .subscribe { viewModel -> }o class ProfilePresenter : Consumer { override fun accept(event: Event) { }a }z View Presenter

Slide 50

Slide 50 text

events .subscribe(presenter) .subscribe { viewModel -> }o class ProfilePresenter : Consumer { override fun accept(event: Event) { }a }z View Presenter

Slide 51

Slide 51 text

events .subscribe(presenter) .subscribe { viewModel -> }o class ProfilePresenter : Consumer { override fun accept(event: Event) { event.flatMap {} }a }z View Presenter

Slide 52

Slide 52 text

Observable.just(1, 2, 3) .subscribe { int -> Observable.just(int * 3) .subscribe { println(it) } }

Slide 53

Slide 53 text

Option B Passing events to the Presenter

Slide 54

Slide 54 text

events. .subscribe { viewModel -> }o class ProfilePresenter(val events:Observable) { }z View Presenter

Slide 55

Slide 55 text

events. .subscribe { viewModel -> }o class ProfilePresenter(val events:Observable) { init { events.flatMap { event -> } }a }z View Presenter

Slide 56

Slide 56 text

presenter(events) .subscribe { viewModel -> }o class ProfilePresenter(val events:Observable) { init { events.flatMap { event -> } }a }z View Presenter

Slide 57

Slide 57 text

Option C Passing events to the Presenter

Slide 58

Slide 58 text

presenter.somefunction(events) .subscribe { viewModel -> }o class ProfilePresenter { fun somefunction(events: Observable) { events.flatMap { event -> } } } View Presenter

Slide 59

Slide 59 text

Passing view models to the View

Slide 60

Slide 60 text

Option A Passing view models to the View

Slide 61

Slide 61 text

presenter.viewmodels() .subscribe { viewModel -> }o class ProfilePresenter { fun viewmodels(): Observable { } } View Presenter

Slide 62

Slide 62 text

Option B Passing view models to the View

Slide 63

Slide 63 text

presenter .subscribe { viewModel -> }o class ProfilePresenter: Observable() { override fun subscribeActual(observer: Observer) { } } View Presenter

Slide 64

Slide 64 text

Option C Passing view models to the View

Slide 65

Slide 65 text

presenter .subscribe() class ProfilePresenter: ObservableSource { override fun subscribe(observer: Observer) { }a }z View Presenter

Slide 66

Slide 66 text

presenter .subscribe(object : Observer { override fun onComplete() {} override fun onSubscribe(d: Disposable) {} override fun onNext(t: ViewModel) {} override fun onError(e: Throwable) {} }) class ProfilePresenter: ObservableSource { override fun subscribe(observer: Observer) { }a }z View Presenter

Slide 67

Slide 67 text

Observable.wrap(presenter) .subscribe { viewModel -> }o class ProfilePresenter: ObservableSource { override fun subscribe(observer: Observer) { }a }z View Presenter

Slide 68

Slide 68 text

Writing is good. Thinking is better.

Slide 69

Slide 69 text

fun presenter():

Slide 70

Slide 70 text

fun presenter(events: Observable):

Slide 71

Slide 71 text

fun presenter(events: Observable): Observable

Slide 72

Slide 72 text

interface ObservableTransformer {a /** * Applies a function to the upstream Observable and returns an ObservableSource with * optionally different element type. */ fun apply(upstream: Observable): ObservableSource }b

Slide 73

Slide 73 text

interface ObservableTransformer {a fun apply(upstream: Observable): ObservableSource }b

Slide 74

Slide 74 text

interface ObservableTransformer {a fun apply(events: Observable): ObservableSource }b

Slide 75

Slide 75 text

interface ObservableTransformer {a fun apply(events: Observable): ObservableSource }b

Slide 76

Slide 76 text

class Presenter: ObservableTransformer {a fun apply(events: Observable): ObservableSource }b

Slide 77

Slide 77 text

class Presenter: ObservableTransformer {a fun apply(events: Observable): ObservableSource }b events .compose(presenter) .subscribe { viewModel -> }o View Presenter

Slide 78

Slide 78 text

class Presenter: ObservableTransformer {a fun apply(events: Observable): ObservableSource }b val testObserver = events // PublishSubject .compose(presenter) .test() // TestObserver Test Presenter

Slide 79

Slide 79 text

class Presenter: ObservableTransformer {a fun apply(events: Observable): ObservableSource }b val testObserver = events // PublishSubject .compose(presenter) .test() // TestObserver events.onNext(EditName("Georges")) testObserver.assertValue(ViewModel()) Test Presenter

Slide 80

Slide 80 text

Thinking is good. Config Changes is better.

Slide 81

Slide 81 text

presenter.viewModels() .subscribe { viewModel -> }o class ProfilePresenter {j }u View Presenter

Slide 82

Slide 82 text

presenter.viewModels() .subscribe { viewModel -> }o class ProfilePresenter {j val events = PublishSubject.create() fun passEvents(events: Observable) {k events.subscribe(this.events) }l }u View Presenter

Slide 83

Slide 83 text

presenter.viewModels() .subscribe { viewModel -> }o class ProfilePresenter {j val events = PublishSubject.create() fun passEvents(events: Observable) {k events.subscribe(this.events) }l fun viewModels() {o return events
 .businessLogic() }i }u View Presenter

Slide 84

Slide 84 text

presenter.viewModels() .subscribe { viewModel -> }o class ProfilePresenter {j val events = PublishSubject.create() fun passEvents(events: Observable) {k events.subscribe(this.events) }l fun viewModels() {o return events
 .businessLogic()
 .replay(1)
 .autoConnect(0) }i }u View Presenter

Slide 85

Slide 85 text

presenter.viewModels() .subscribe { viewModel -> }o class ProfilePresenter {j val events = PublishSubject.create() fun passEvents(events: Observable) {k events.subscribe(this.events) }l fun viewModels() {o return events
 .businessLogic()
 .replay(1)
 .autoConnect(0) }i }u View Presenter

Slide 86

Slide 86 text

presenter.viewModels() .subscribe { viewModel -> }o
 presenter.passEvents(events) class ProfilePresenter {j val events = PublishSubject.create() fun passEvents(events: Observable) {k events.subscribe(this.events) }l fun viewModels() {o return events
 .businessLogic()
 .replay(1)
 .autoConnect(0) }i }u View Presenter

Slide 87

Slide 87 text

Unidirectional Data Flow

Slide 88

Slide 88 text

VIEW PRESENTER

Slide 89

Slide 89 text

VIEW PRESENTER (BUSINESS LOGIC) READING WRITING

Slide 90

Slide 90 text

VIEW PRESENTER (BUSINESS LOGIC) VIEW (READING) VIEW (WRITING)

Slide 91

Slide 91 text

VIEW (READING) VIEW (WRITING) PRESENTER (BUSINESS LOGIC)

Slide 92

Slide 92 text

VIEW (READING) VIEW (WRITING) PRESENTER (BUSINESS LOGIC)

Slide 93

Slide 93 text

New Feature? No Problem.

Slide 94

Slide 94 text

sealed class Event { data class EditName(val newName: String) : Event() }a data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName )b class ProfileViewRemix { fun onStart() {t events .compose(presenter) .subscribe { viewModel -> // rendering view model }o }i }t

Slide 95

Slide 95 text

sealed class Event { data class EditName(val newName: String) : Event() }a data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName )b class ProfileViewRemix { fun onStart() {t events .compose(presenter) .subscribe { viewModel -> // rendering view model }o }i }t

Slide 96

Slide 96 text

sealed class Event { data class EditName(val newName: String) : Event() data class ChangeAvatar(val picture: File) : Event() }a data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName )b class ProfileViewRemix { fun onStart() {t events .compose(presenter) .subscribe { viewModel -> // rendering view model }o }i }t

Slide 97

Slide 97 text

sealed class Event { data class EditName(val newName: String) : Event() data class ChangeAvatar(val picture: File) : Event() }a data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName, val avatarUri: Uri )b class ProfileViewRemix { fun onStart() {t events .compose(presenter) .subscribe { viewModel -> // rendering view model }o }i }t

Slide 98

Slide 98 text

sealed class Event { data class EditName(val newName: String) : Event() data class ChangeAvatar(val picture: File) : Event() }a data class ViewModel( val stuff: Any?, val prefixedName: PrefixedName, val avatarUri: Uri )b class ProfileViewRemix { fun onStart() {t events .compose(presenter) .subscribe { viewModel -> // rendering view model Picasso.get().load(viewModel.avatarUri).into(avatarView) }o }i }t

Slide 99

Slide 99 text

class ProfilePresenter : ObservableTransformer {a override fun apply(events: Observable): ObservableSource {d return events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) }s }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )f }g })h }j }k

Slide 100

Slide 100 text

class ProfilePresenter : ObservableTransformer {a override fun apply(events: Observable): ObservableSource {d return events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) }s }d }f .startWith(NameValid(event.newName)) }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )f }g })h }j }k

Slide 101

Slide 101 text

class ProfilePresenter : ObservableTransformer {a override fun apply(events: Observable): ObservableSource {d return events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) }s }d }f .startWith(NameValid(event.newName)) is ChangeAvatar -> appService.changeAvatar(event.picture) .map { response -> AvatarValid(response.uri) } }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )f }g })h }j }k

Slide 102

Slide 102 text

class ProfilePresenter : ObservableTransformer {a override fun apply(events: Observable): ObservableSource {d return events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) }s }d }f .startWith(NameValid(event.newName)) is ChangeAvatar -> appService.changeAvatar(event.picture) .map { response -> AvatarValid(response.uri) } .onErrorReturn { throwable -> AvatarInvalid(throwable) } }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )f }g })h }j }k

Slide 103

Slide 103 text

class ProfilePresenter : ObservableTransformer {a override fun apply(events: Observable): ObservableSource {d return events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) }s }d }f .startWith(NameValid(event.newName)) is ChangeAvatar -> appService.changeAvatar(event.picture) .map { response -> AvatarValid(response.uri) } .onErrorReturn { throwable -> AvatarInvalid(throwable) } }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )f is AvatarValid -> previous.copy(avatarUri = result.uri) }g })h }j

Slide 104

Slide 104 text

override fun apply(events: Observable): ObservableSource {d return events.flatMap { event -> when (event) {y is EditName -> appService.setName(event.newName) .map { response -> when {u response.isValid -> NameValid(response.name) response.isInvalid -> NameInvalid.also { navigator.goTo(response) }s }d }f .startWith(NameValid(event.newName)) is ChangeAvatar -> appService.changeAvatar(event.picture) .map { response -> AvatarValid(response.uri) } .onErrorReturn { throwable -> AvatarInvalid(throwable) } }g }h .mergeWith(appService.profile().map(::ProfileResult)) .scan(ViewModel(stuff = null, prefixedName = PrefixedName("", "")), BiFunction { previous: ViewModel, result: Result -> when (result) {j is NameValid -> previous.copy(prefixedName = previous.prefixedName.copy(name = result.name)) is NameInvalid -> previous is ProfileResult -> previous.copy( stuff = result.profile, prefixedName = PrefixedName(result.profile.prefix, result.profile.name) )f is AvatarValid -> previous.copy(avatarUri = result.uri) is AvatarInvalid -> TODO() }g })h }j

Slide 105

Slide 105 text

Architecture forced us to separate concerns No need to touch existing code Easy to test Easy to review

Slide 106

Slide 106 text

Gotta Immutate 'em All! Unidirectional Data Flow Side-Effects Isolation

Slide 107

Slide 107 text

Benoît Quenaudon @oldergod Fin