Architecture réactive avec les Coroutines

PAUG Juillet 2018

Transcript

1. Architecture réactive avec les Coroutines Juliette Dompé Pierre Degand @p_degand
2. Architecture réactive avec les Coroutines (et les Channels) Juliette Dompé Pierre Degand @p_degand
3. De quoi parle-t-on ?
4. De quoi parle-t-on ? dependencies { implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${versions.kotlin}" }
5. De quoi parle-t-on ? dependencies { implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${versions.kotlin}" implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:${versions.coroutines}" implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:${versions.coroutines}" } kotlin { experimental { coroutines 'enable' } }
6. De quoi parle-t-on ? dependencies { implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${versions.kotlin}" implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:${versions.coroutines}" implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:${versions.coroutines}" implementation "androidx.lifecycle:lifecycle-livedata:${versions.lifecycle}" implementation "androidx.lifecycle:lifecycle-extensions:${versions.lifecycle}" kapt "androidx.lifecycle:lifecycle-compiler:${versions.lifecycle}" } kotlin { experimental { coroutines 'enable' } }
7. Les Coroutines - Kessékessa ?
8. Les Coroutines - Kessékessa ? Unité de calcul suspendable
9. Les Coroutines - Kessékessa ? Unité de calcul suspendable Exprimer du code asynchrone et non bloquant de manière synchrone
10. (avant) Les Coroutines fun requestTokenAsync(callback: (String) -> Unit) {} fun createUserAsync(token: String, callback: (User) -> Unit) {} fun displayUser(user: User) {}
11. (avant) Les Coroutines fun requestTokenAsync(callback: (String) -> Unit) {} fun createUserAsync(token: String, callback: (User) -> Unit) {} fun displayUser(user: User) {} fun callbacks() { requestTokenAsync { token -> createUser(token) { user -> displayUser(user) } } }
12. Les Coroutines fun coroutines() { val token = requestToken() val user = createUser(token) displayUser(user) }
13. Les Coroutines fun requestToken(): String {} fun createUser(token: String): User {} fun displayUser(user: User) {} fun coroutines() { val token = requestToken() val user = createUser(token) displayUser(user) }
14. Les Coroutines suspend fun requestToken(): String {} suspend fun createUser(token: String): User {} fun displayUser(user: User) {} fun coroutines() { val token = requestToken() val user = createUser(token) displayUser(user) }
15. Les Coroutines suspend fun requestToken(): String {} suspend fun createUser(token: String): User {} fun displayUser(user: User) {} fun coroutines() { launch { val token = requestToken() val user = createUser(token) displayUser(user) } }
16. Les Coroutines suspend fun requestToken(): String {} suspend fun createUser(token: String): User {} fun displayUser(user: User) {} fun coroutines() { launch(context = CommonPool) { val token = requestToken() val user = createUser(token) withContext(UI) { displayUser(user) } } }
17. Les Coroutines suspend fun requestToken(): String {} suspend fun createUser(token: String): User {} fun displayUser(user: User) {} fun coroutines() { launch(context = CommonPool) { val token = requestToken() val user = createUser(token) withContext(UI) { displayUser(user) } } } KotlinConf 2017 - Introduction to Coroutines by Roman Elizarov https://youtu.be/_hfBv0a09Jc KotlinConf 2017 - Deep Dive into Coroutines on JVM by Roman Elizarov https://youtu.be/YrrUCSi72E8
18. Les Channels interface Channel<E> { }
19. Les Channels interface Channel<E> : SendChannel<E>{ fun send(element: E) }
20. Les Channels interface Channel<E> : SendChannel<E>, ReceiveChannel<E> { fun send(element: E) fun receive(): E }
21. Les Channels interface Channel<E> : SendChannel<E>, ReceiveChannel<E> { suspend fun send(element: E) suspend fun receive(): E }
22. Les Channels interface Channel<E> : SendChannel<E>, ReceiveChannel<E> { suspend fun send(element: E) suspend fun receive(): E } val channel = Channel<Int>() launch { repeat(5) { print(channel.receive()) } } launch { for (x in 1..5) channel.send(x * x) }
23. Les Channels - Iterator interface Channel<E> : SendChannel<E>, ReceiveChannel<E> { suspend fun send(element: E) suspend fun receive(): E operator fun iterator(): ChannelIterator<E> } interface ChannelIterator<out E> { suspend operator fun hasNext(): Boolean suspend operator fun next(): E }
24. Les Channels - Iterator interface Channel<E> : SendChannel<E>, ReceiveChannel<E> { suspend fun send(element: E) suspend fun receive(): E operator fun iterator(): ChannelIterator<E> } interface ChannelIterator<out E> { suspend operator fun hasNext(): Boolean suspend operator fun next(): E } val channel = Channel<Int>() launch { for (value in channel) { print(value) } } launch { for (x in 1..5) channel.send(x * x) channel.close() }
25. Les Channels - Capacity val channel = Channel<Int>(capacity = Int)
26. Les Channels - Capacity val channel = Channel<Int>(capacity = Int) public fun <E> Channel(capacity: Int): Channel<E> = when (capacity) { 0 -> RendezvousChannel() }
27. Les Channels - Capacity val channel = Channel<Int>(capacity = Int) public fun <E> Channel(capacity: Int): Channel<E> = when (capacity) { 0 -> RendezvousChannel() else -> ArrayChannel(capacity) }
28. Les Channels - Capacity val channel = Channel<Int>(capacity = Int) public fun <E> Channel(capacity: Int): Channel<E> = when (capacity) { 0 -> RendezvousChannel() Channel.UNLIMITED -> LinkedListChannel() else -> ArrayChannel(capacity) }
29. Les Channels - Capacity val channel = Channel<Int>(capacity = Int) public fun <E> Channel(capacity: Int): Channel<E> = when (capacity) { 0 -> RendezvousChannel() Channel.UNLIMITED -> LinkedListChannel() Channel.CONFLATED -> ConflatedChannel() else -> ArrayChannel(capacity) }
30. Les Channels val channel = Channel<Int>() launch { print("channel#1 ${channel.receive()}") } launch { print("channel#2 ${channel.receive()}") } launch { channel.send(1) }
31. Les Channels val channel = Channel<Int>() launch { print("channel#1 ${channel.receive()}") } launch { print("channel#2 ${channel.receive()}") } launch { channel.send(1) } > channel#1 1
32. Les Channels - Broadcast val channel = BroadcastChannel<Int>(1) launch { println("channel#1 ${channel.openSubscription().receive()}") } launch { println("channel#2 ${channel.openSubscription().receive()}") } launch { channel.send(1) } > channel#1 1 > channel#2 1
33. Model Réactif interface UserStore { val user: User fun setName(name: String) fun setAge(age: Int) }
34. Model Réactif interface UserStore { val user: User fun setName(name: String) fun setAge(age: Int) } Pas très réactif ...
35. Model Réactif interface UserStore { val user: ReceiveChannel<User> suspend fun setName(name: String) suspend fun setAge(age: Int) }
36. Model Réactif class UserStoreImpl : UserStore { private val _user = ConflatedBroadcastChannel<User>() override val user: ReceiveChannel<User> get() = _user.openSubscription() override suspend fun setName(name: String) { val newUser = // on update le user sur une API par exemple ... _user.send(newUser) } override suspend fun setAge(age: Int) { val newUser = // on update le user sur une API par exemple ... _user.send(newUser) } }
37. Model Réactif class UserViewModel(val userStore: userStore) : ViewModel() { private val parentJob = Job() val userLiveData = MutableLiveData<User>() init { launch(context = UI, parent = parentJob) { for (user in userStore.user) { userLiveData.value = user } } } override fun onCleared() { parentJob.cancel() } }
38. Model Réactif class UserViewModel(val userStore: UserStore, val userPresenter: UserPresenter) : ViewModel() { private val parentJob = Job() val userLiveData = MutableLiveData<UserView>() init { launch(context = UI, parent = parentJob) { userStore.user.map { user -> userPresenter.presentUser(user) }.consumeEach { userView -> userLiveData.value = userView } } } ... }
39. Channels - Extensions fun <T, R> ReceiveChannel<T>.toLiveData( parent: Job, context: CoroutineContext, block: (T) -> R ): LiveData<R> { val liveData = MutableLiveData<R>() launch(parent = parent, context = context) { consumeEach { liveData.postValue(block(it)) } } return liveData }
40. Model Réactif class UserViewModel(userStore: UserStore, userPresenter: UserPresenter) : ViewModel() { private val parentJob = Job() val userLiveData = userStore.user.toLiveData( context = UI, parent = parentJob, block = userPresenter::presentUser ) }
41. Model Réactif class UserViewModel( private val userStore: UserStore, userPresenter: UserPresenter ) : ViewModel() { ... val userLiveData = userStore.user.toLiveData( context = UI, parent = parentJob, block = userPresenter::presentUser) fun updateUserName(newName: String) { launch(context = CommonPool, parent = parentJob) { userStore.setName(newName) } } }
42. Architecture
43. Référence ultime : https://github.com/Kotlin/kotlinx.coroutines • Tous les liens utiles (confs, doc) sont dans le README
44. Merci ! Référence ultime : https://github.com/Kotlin/kotlinx.coroutines • Tous les liens utiles (confs, doc) sont dans le README Juliette Dompé Pierre Degand @p_degand