Kotlin Coroutines ことはじめ

Kotlin Coroutines ͜ͱ͸͡Ί

ࣗݾ঺հ • w ழມॆԝ ͍ͷ·ͨΈͭͻΖ w ᷂UFDIWFJO୅දɻ  J04"OESPJEεϚϗΞϓϦΤϯδχΞɻ  3Y͕޷͖Ͱ͢ɻ
w QSJWBUFUXJUUFS!JOP

ࠓ೔ͷ࿩ • Kotlinίϧʔνϯͷجຊͱ࢓૊ΈΛ஌Ζ͏

ҰൠతʹɺCoroutine ͱ͸ • தஅɾ࠶։͕Մೳͳαϒϧʔνϯ • ฒߦੑ(Concurrent)Λఏڙ͢Δ

αϒϧʔνϯʹී௨ͷؔ਺(ͳͲ) αϒϧʔνϯ ؔ਺ͳͲ ॲཧ ॲཧ ॲཧ ʜ SFUVSOl)FMMP 8PSMEl ϝΠϯॲཧ
αϒϧʔνϯ։࢝ ʜ αϒϧʔνϯऴྃ

ίϧʔνϯʹதஅՄೳͳαϒϧʔνϯ ίϧʔνϯ ॲཧ ZJFMElIFMMPz ॲཧ ZJFMElXPSMEz ॲཧ ʜ ϝΠϯॲཧ ίϧʔνϯ։࢝
ʜ ίϧʔνϯऴྃ

ίϧʔνϯ͸ ฒߦ(Concurrent)ʹಈ࡞͢Δ εϨου" ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ εϨου# ίϧʔνϯ ίϧʔνϯ
ίϧʔνϯ ίϧʔνϯ

ฒߦ(Concurrent) ͱ ฒྻ(Parallel) • ฒߦ(Concurrent) ͷྫ: Coroutine • ฒྻ(Parallel) ͷྫ:
ϚϧνεϨουɾϚϧνϓ ϩηε

ฒߦ(Concurrent) != ฒྻ(Parallel) εϨου" ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ͜Ε͸ฒߦͰ͋ͬͯ  ฒྻͰ͸ͳ͍
͜Ε͸ฒߦͰ΋  ฒྻͰ΋͋Δ εϨου# εϨου" ίϧʔνϯ ίϧʔνϯ

Coroutines   are   light-weight.

Kotlin Coroutines

Kotlin Coroutine ͷΩϞ • Suspending Function • Structured concurrency •
CoroutineContext • Async as Sync

Kotlin CoroutineͷΩϞᶃ  Suspending Function

Suspending Function • Kotlin Coroutines ͸ɺίϧʔνϯͷதஅͰ͖ Δੑ࣭Λ suspend ؔ਺(Suspending Function)Ͱ࣮ݱ͍ͯ͠Δɻ

Suspending Function ͷੑ࣭ • suspend ؔ਺͸ଞͷ suspend ؔ਺ͷதͰ͔͠ ࣮ߦͰ͖ͳ͍ɻ •
ࢠͷ suspend ؔ਺͕தஅ͢Δͱɺ਌ͷ suspend ؔ਺΋ࢭ·Δɻ • suspend ؔ਺ͷதͰී௨ͷؔ਺(suspendͰͳ ͍ؔ਺)ΛݺͿ͜ͱ͸Ͱ͖Δɻ

Hello world to Kotlin Coroutine

͜ͷαϯϓϧͰ࢖͍ͬͯΔؔ਺ • ίϧʔνϯϏϧμʔ(ੜ੒ؔ਺): • runBlocking<T> { ... } • CoroutineScope#launch
{ ... } • suspendؔ਺:  delay(timeMillis: Long) ※஫: runBlocking͸ཚ༻NGɻ  ɹɹAndroid؀ڥͰ͸࢖Θͳ͍͜ͱʂ

Android ൛

CoroutineScopeΫϥε • ίϧʔνϯͷੜଘظؒΛ؅ཧ͢ΔΦϒδΣΫτɻ • MainScope ... UIεϨουͰಈ࡞͢Δείʔϓɻ   → AndroidͷActivity
ͳͲͱඥ෇͚ͯը໘ͷ  ɹϥΠϑαΠΫϧͱҰகͤ͞ΒΕΔɻ • GlobalScope ... ΞϓϦͷੜଘظؒͱಉ͡είʔϓɻ  → όονॲཧͳͲɺΞϓϦੜଘதʹऴΘͬͯ͸ࠔΔॲཧΛ࣮ߦ͢Δɻ

αεϖϯυؔ਺ͷྫ • delay (timeMillis: Long)   ... ࢦఆϛϦඵ଴ͭɻ • withTimeout<T>(timeMillis:
Long) { ... } withTimeoutOrNull<T>(timeMillis: Long) { ...}  ... ϒϩοΫ಺ͷॲཧ͕ࢦఆϛϦඵΛ௒͑ͨͱ͖ʹ  ɹλΠϜΞ΢τͤ͞Δɻ • yield()   ... ॲཧΛॠஅͯ͠ɺ(͋Ε͹)ଞͷίϧʔνϯʹॲཧΛճ͢ɻ

suspend ͸ϊϯϒϩοΩϯά • suspend = தஅ • ͚ͩͲɺεϨουΛϒϩοΫ͠ͳ͍ • →εϨουΛϒϩοΫ͢Δྫ:
Thread.sleep()

Coroutine ͷ suspend ؔ਺͸ॲཧΛதஅͯ͠ɺ ଞͷฒߦॲཧதͷίϧʔνϯʹεϨουΛৡΔɻ εϨου" ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ
ZJFME

εϨου" ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ZJFME

εϨου" ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ZJFME ZJFME ZJFME

Suspend Function Ͱ ίϧʔνϯͷதஅͰ͖Δੑ࣭Λ ࣮ݱ͍ͯ͠Δ

Kotlin CoroutineͷΩϞᶄ  Structured Concurrency

Structured concurrency ฒߦੑͷߏ଄Խ • ίϧʔνϯ͸਌ࢠؔ܎Λ࣋ͯΔɻ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ

Α͋͘ΔϚϧνεϨουͳ  ඇಉظॲཧͷ໰୊ • Ұ෦ͷεϨουΛམͱͨ͠(མͪͨ)ͱ͖ʹɺ  ࢒ΓͷεϨουΛڠௐͤ͞Δͷ͕େมɻ • λΠϛϯά໰୊ͰσουϩοΫͨ͠Γɺҙਤ͠ͳ ͍ڍಈ͕ى͜Γ΍͍͢ɻ • ໰୊͕ى͖ͨͱ͖ʹݪҼڀ໌ɾσόοά͕೉͠
͍ɻ

਌ࢠؔ܎ͷ͋Δίϧʔνϯ͸  ڠௐͤ͞΍͍͢

਌ࢠؔ܎ͷ͋Δίϧʔνϯ͸  ڠௐͤ͞΍͍͢ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ΞΫςΟϒͳ ίϧʔνϯ

਌͸ࢠڙͷऴྃΛ଴ͬͯऴྃ͢Δ ΞΫςΟϒͳ ίϧʔνϯ ଴ػதͷ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ
ίϧʔνϯ

਌ࢠؔ܎ͷ͋Δίϧʔνϯ͸  ྫ֎ɾΩϟϯηϧ࣌΋ڠௐͤ͞΍͍͢

਌ࢠؔ܎ͷ͋Δίϧʔνϯ͸  ྫ֎ɾΩϟϯηϧ࣌΋ڠௐͤ͞΍͍͢ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ྫ֎ൃੜʂ

਌ίϧʔνϯʹྫ֎Λ఻೻ͯ͠  ίϧʔνϯΛऴྃ͢Δ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ྫ֎ൃੜʂ ྫ֎εϩʔ ྫ֎εϩʔ

਌ίϧʔνϯ͕ऴྃ͢Δ࣌͸ɺ  ࢠίϧʔνϯ΋Ωϟϯηϧ͢Δ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ ྫ֎ൃੜʂ KPCDBODFM KPCDBODFM

ʹ਌ίϧʔνϯΛࢭΊΕ͹ɺ ࢠίϧʔνϯ΋ࢭ·Δ

਌ࢠϧʔνϯͷείʔϓΛ Ωϟϯηϧ͢Ε͹ɺ ਌ࢠͱ΋Ͳ΋ࢭΊΒΕΔ

ίϧʔνϯͷ࣮ߦείʔϓΛ  Ωϟϯηϧ͢Δ͚ͩͰશ෦ࢭΊΒΕΔ ίϧʔνϯ .BJO4DPQF KPCDBODFM "DUJWJUZ PO%FTUSPZ TDPQFDBODFM ίϧʔνϯ KPCDBODFM

(࠶ܝ) Android Hello world

ίϧʔνϯ͸Ͳ͏΍ͬͯ ਌ࢠؔ܎Λ࡞͍ͬͯΔͷ͔ʁ → CoroutineScope

launch ͷϥϜμࣜ͸  this = CoroutineScope

ίϧʔνϯ .BJO4DPQF KPCDBODFM "DUJWJUZ PO%FTUSPZ TDPQFDBODFM ίϧʔνϯ ίϧʔνϯ KPCDBODFM (MPCBM4DPQF
GlobalScopeͷίϧʔνϯ͸.BJO4DPQFͱؔ܎ͳ͘ಈ͘ʂ launch launch launch

Structured Concurrency Λ ׆༻͢Ε͹ ίϧʔνϯ؅ཧָ͕ʹͳΔ

Kotlin CoroutineͷΩϞᶅ  CoroutineContext

CoroutineContext %JTQBUDIFSɿ.BJO +PCɿͳ͠ ϝΠϯείʔϓͷίϯςΩετ %JTQBUDIFSɿ.BJO +PCɿίϧʔνϯ είʔϓ1ͷίϯςΩετ %JTQBUDIFSɿ.BJO +PCɿίϧʔνϯ είʔϓͷίϯςΩετ
%JTQBUDIFSɿ%FGBVMU +PCɿίϧʔνϯ είʔϓͷίϯςΩετ ϝΠϯείʔϓ ίϧʔνϯ ίϧʔνϯ ίϧʔνϯ1ͷείʔϓ είʔϓ ίϧʔνϯͷείʔϓ είʔϓ ίϧʔνϯ ίϧʔνϯͷείʔϓ είʔϓ

CoroutineContextͷྫ: Job  ͋Δίϧʔνϯͷ࣮ߦΛද͢Πϯελϯε • ίϧʔνϯΛ࣮ߦ͢ΔͱJobΛ͔͑͢ɻ

CoroutineContextͷྫ: CorouttineDispatcher  ίϧʔνϯΛͲͷεϨουͰಈ͔͔͢ΛܾΊΔਓ • Dispatches.Main • Dispatchers.Default • Dispatchers.IO •
Dispatchers.Unconﬁned • ͦͷଞ: newSingleThreadContext("threadName") ͳͲ

CoroutinenContextͷྫ:ͦͷଞ • CoroutineName("name") • NonCancellable • CoroutineExceptionHandler {}

CoroutineContextͷ࢖͍ํ • ίϧʔνϯϏϧμʔͷҾ਺ʹࢦఆͯ͠࢖͏ • + Ͱ࿈݁ʢॏෳͨ͠ઃఆ͸ӈล༏ઌʣͯ͠૊Έ߹ Θͤͯ࡞Δ

CoroutineContextͷ࢖͍ํ • ಉظతʹৼΔ෣ͬͯ͘ΕΔ withContext ͕ศར

Kotlin CoroutineͷΩϞᶅ  Async as Sync

TwitterΫϥΠΞϯτతͳ ΞϓϦ࣮૷ΛίϧʔνϯͰߟ͑Δɻ ϩάΠϯ 0, λΠϜϥΠϯऔಘ < l͓͸Α͏z lࠓ೔͸ษڧձͰ͢z >

ίϧʔνϯ͸ඇಉظ • ྫ: ϩάΠϯͯ͠λΠϜϥΠϯऔಘ͢ΔAPI࣮૷

ίϧʔνϯ͸ඇಉظʁ • ඇಉظॲཧΛಉظతͳײ֮Ͱखଓ͖తʹॻ͚Δ

ίϧʔνϯ͸ඇಉظॲཧΛಉظ తʢखଓ͖తʣʹॻ͚Δ • ಉظతʹॻ͚ΔͷͰɺ௚ײతͰɺόάΛຒΊࠐΈ ʹ͍͘ɻ(σουϩοΫɾ࣮ߦλΠϛϯά໰୊) • ͳΜͱ͔Listener΍ίʔϧόοΫ஍ࠈ͔Βͷղ์ɻ

async / await ΋͋Δ • async ίϧʔνϯͰɺඇಉظίϧʔνϯʹͭͭ͠ɺ ݁ՌΛ଴ͭ͜ͱ΋Ͱ͖Δ • async
= ݁ՌΛड͚औΕΔػೳΛ΋ͭ launchɻ

Kotlin ίϧʔνϯͷ جຊ͸͜Ε͚ͩ

Kotlin Coroutineͷ ศརͳػೳͷ঺հ

flow ίϧʔνϯ • flow = γʔέϯεͰॱ࣍݁ՌΛྲྀ͢ async. • Rx ObservableΛࢀߟʹ࡞ΒΕ͍ͯΔɻ
• map(transform{}), flatMap,ϑΟϧλ,  ྫ֎෮ؼॲཧ(catch{}), εϨου੾Γସ͑, combineLatest, zip ͳͲ΋͋Δɻ

Channels, produce, actor • Channel<T> ͸ίϧʔνϯؒͷ૒ํ޲ͷσʔ λ΍ΓऔΓʹ͔ͭ͑ΔΦϒδΣΫτɻ • produce<T> {
} ... ࢠ͕ૹ৴ͯ͠਌͕ड৴͢Δ Ұํ޲νϟϯωϧΛ࡞Δίϧʔνϯɻ • actor<T> { } ... ਌͕ૹ৴ͯ͠ࢠ͕ड৴͢ΔҰํ ޲νϟωϧΛ࡞Δίϧʔνϯɻ

AndroidXͰ࢖͑Δศརͳػೳ • ViewModelScope • LifecycleScope • liveData<T> { LiveDataScope<T> ->
Unit ... }: LiveData<T>

Kotlin Coroutines ことはじめ

Kotlin Coroutines ことはじめ

More Decks by M.Inomata

Other Decks in Technology

Featured

Transcript