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Kotlin Coroutine入門
AAkira @ CA.kt
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$ whois
private lateinit var aakira: User
data class User(val name: String, val twitterId: String,
val githubId: String, val company: String)
println("Name : ${aakira.name}")
println("Twitter Id : ${aakira.twitterId}")
println("Github Id : ${aakira.githubId}")
println("Company : ${aakira.company}")
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@_a_akira
AAkira
CyberAgent, Inc.
Akira Aratani
private lateinit var aakira : User
data class User(val name: String, val twitterId: String, val githubId: String, val company: String)
print("Name : ${aakira.name}”)
println("Github Id : ${aakira.githubId}")
print("Twitter Id : ${aakira.twitterId}")
println("Company : ${aakira.company}")
$ whois
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@_a_akira
AAkira
CyberAgent, Inc.
Akira Aratani
private lateinit var aakira : User
data class User(val name: String, val twitterId: String, val githubId: String, val company: String)
print("Name : ${aakira.name}”)
println("Github Id : ${aakira.githubId}")
print("Twitter Id : ${aakira.twitterId}")
println("Company : ${aakira.company}")
$ whois
,PUMJOॿಡຊॻ͍ͨIUUQTHPPHM"$K')
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About
• 生放送配信プラットフォーム ≠ AbemaTV
• 最近 アプリを縦化!
FRESH! AndroidアプリのUI/UX : https://developers.cyberagent.co.jp/blog/archives/7177
• Full Kotlin
• 使ってるLibraryは大体最新
(Kotlin1.1, Rx2, Dagger2, Retrofit2, Ok3, ExoPlayer2 etc)
• もちろんコルーチンも一部で導入済み
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私とKotlin
M1 2012-04-12
M11 2015-03-19
M14 2015-10-01
1.0-beta4 2015-12-22
M13 2015-09-16
1.0 2016-02-16
1.0-RC 2016-02-04
2016-01-21 Release
2015-04 開発開始
kotlin
FRESH
1.1 2017-03-01
2017-05-15 Renewal
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About coroutine
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About Coroutine
• Kotlin 1.1で導入された非同期プログラミングのための機能
≠ Thread : 特定のスレッドに属していないので、再開先は別のスレッドで動作可能
• 1.1ではまだExperimentalなので、仕様変更の可能性あり
• 言語機能ではなく、ライブラリとして提供されている
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Introduce Coroutine
def kotlinCoroutinesVersion = "0.15"
// for core
compile “org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinCoroutinesVersion”
// for JDK8
compile “org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:$kotlinCoroutinesVersion”
// for Asynchronous IO on JDK7+
compile “org.jetbrains.kotlinx:kotlinx-coroutines-nio:$kotlinCoroutinesVersion"
// for RxJava2
compile “org.jetbrains.kotlinx:kotlinx-coroutines-rx2:$kotlinCoroutinesVersion"
// for Android
compile “org.jetbrains.kotlinx:kotlinx-coroutines-android:$kotlinCoroutinesVersion"
// for Swing
compile “org.jetbrains.kotlinx:kotlinx-coroutines-swing:$kotlinCoroutinesVersion"
// for JavaFX
compile “org.jetbrains.kotlinx:kotlinx-coroutines-javafx:$kotlinCoroutinesVersion"
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Introduce Coroutine
// for core
compile “org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinCoroutinesVersion”
// for JDK8
compile “org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:$kotlinCoroutinesVersion”
// for Asynchronous IO on JDK7+
compile “org.jetbrains.kotlinx:kotlinx-coroutines-nio:$kotlinCoroutinesVersion"
// for RxJava2
compile “org.jetbrains.kotlinx:kotlinx-coroutines-rx2:$kotlinCoroutinesVersion"
// for Android
compile “org.jetbrains.kotlinx:kotlinx-coroutines-android:$kotlinCoroutinesVersion"
// for Swing
compile “org.jetbrains.kotlinx:kotlinx-coroutines-swing:$kotlinCoroutinesVersion"
// for JavaFX
compile “org.jetbrains.kotlinx:kotlinx-coroutines-javafx:$kotlinCoroutinesVersion"
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Elements of coroutine
• Suspending functions
• Coroutine builders (Suspending lambda)
• Coroutine dispatchers (Coroutine context)
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Suspending functions
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Suspending functions
• コルーチンの実行を中断することができる関数
• 通常のコードから呼び出すことはできない
• 他のSuspending function, Coroutine Builder(Suspending lambda)からのみ
呼び出すことが可能
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Suspending functions
suspend fun hoge(): Int {
delay(10, TimeUnit.SECONDS)
return 100
}
10秒後に100を返すsuspend関数
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Suspending functions
delayもsuspend関数
suspend fun delay(time: Long, unit: TimeUnit = TimeUnit.MILLISECONDS) {
require(time >= 0) { "Delay time $time cannot be negative" }
if (time <= 0) return // don't delay
return suspendCancellableCoroutine sc@ { cont: CancellableContinuation ->
val delay = cont.context[ContinuationInterceptor] as? Delay
if (delay != null)
delay.scheduleResumeAfterDelay(time, unit, cont)
else
cont.cancelFutureOnCompletion(
scheduledExecutor.schedule(ResumeRunnable(cont), time, unit))
}
}
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Suspending functions
suspend fun hoge(): Int {
delay(10, TimeUnit.SECONDS)
return 100
}
hogeもsuspend関数なのでdelayを呼び出せる
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Suspending functions
suspend関数を引数にとることも可能
foo({
delay(10, TimeUnit.SECONDS)
"CA.kt"
})
fun foo(bar: suspend () -> String) {
launch(CommonPool) { println(bar.invoke()) }
}
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Suspending functions
10秒後に “CA.kt” と出力される
foo({
delay(10, TimeUnit.SECONDS)
"CA.kt"
})
fun foo(bar: suspend () -> String) {
launch(CommonPool) { println(bar.invoke()) }
}
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Suspending functions
foo({
delay(10, TimeUnit.SECONDS)
"CA.kt"
})
fun foo(bar: suspend () -> String) {
launch(CommonPool) { println(bar.invoke()) }
}
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Coroutine builders (Suspending lambda)
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Coroutine builders
• 引数として(複数の)Suspending Lambdaを取ってコルーチンを作成し、
オプションでその結果へのアクセスを与える関数
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Coroutine builders
Name Result Scope Description
launch Job CoroutineScope Launches coroutine that does not have any result
async Deferred CoroutineScope Returns a single value with the future result
produce ProducerJob ProducerScope Produces a stream of elements
actor ActorJob ActorScope Processes a stream of messages
runBlocking T CoroutineScope Blocks the thread while the coroutine runs
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launch
結果を返さない(Unit)コルーチンを作る
public fun launch(
context: CoroutineContext,
start: CoroutineStart = CoroutineStart.DEFAULT,
block: suspend CoroutineScope.() -> Unit
): Job {
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launch
• 第一引数のCoroutineContextはスレッドの様な実行環境を指定する(次節で解説)
• 第二引数のCoroutineStartはコルーチンを開始するタイミングを指定できる
public fun launch(
context: CoroutineContext,
start: CoroutineStart = CoroutineStart.DEFAULT,
block: suspend CoroutineScope.() -> Unit
): Job {
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async
結果を返すコルーチンを作る
public fun async(
context: CoroutineContext,
start: CoroutineStart = CoroutineStart.DEFAULT,
block: suspend CoroutineScope.() -> T
): Deferred {
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launchとasyncの違い
• launchはJobを返す
• asyncはDeferredを返す
• DeferredはJobのinterface
public interface Deferred : Job {
val isCompletedExceptionally: Boolean
val isCancelled: Boolean
public suspend fun await(): T
public fun registerSelectAwait(select: SelectInstance,
block: suspend (T) -> R)
public fun getCompleted(): T
}
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Others (Coroutine builders)
• 入門としてはlaunchとasyncが使えれば問題ない
• produce, actorはgoroutineのようなChannelの概念がある
produce: sender, actor: receiver
• runBlockingはその名の通りスレッドを止めて動作する
cf: https://github.com/Kotlin/kotlinx.coroutines/blob/master/ui/coroutines-guide-ui.md
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Coroutine dispatchers (Coroutine context)
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Coroutine dispatchers
Name Description
CommonPool Confines coroutine execution to a shared pool of threads
newSingleThreadContext Create new single-threaded coroutine context
newFixedThreadPoolContext Creates new thread pool of a fixed size
Executor.asCoroutineDispatcher Extension to convert any executor
Unconfined Does not confine coroutine execution in any way
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CommonPool
java.util.concurrent.ForkJoinPoolを使って
スレッドプールを作成して良い感じにやってくれる
launch(CommonPool) { }
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newSingleThreadContext
thread poolが1のCoroutine Dispatcherを作成する
launch(newSingleThreadContext("thread name")) { }
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newFixedThreadPoolContext
• newSingleThreadContextのthread pool数を指定できる版
• ソースの中身は一緒
launch(newFixedThreadPoolContext(3, "thread name")) { }
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asCoroutineDispatcher
java.util.concurrentのExecutorをCoroutine Contextに変換出来る
class MyCoroutineExecutor : Executor {
override fun execute(command: Runnable?) { }
}
val myCoroutineExecutor = MyCoroutineExecutor()
launch(myCoroutineExecutor.asCoroutineDispatcher()) { }
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Unconfined
• 特定のスレッドに依らないCoroutine Context
• コルーチンを再開後に特定のスレッドかスレッドプールに限定する必要が
あるが、最初の中断まで現在の呼び出しスレッドで実行したい場合は、前
述のCoroutineBuilderにCoroutineStart.UNDISPATCHEDを設定する
launch(Unconfined) { }
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How to use a Coroutine
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さっき読めなかったやつ
foo({
delay(10, TimeUnit.SECONDS)
"CA.kt"
})
fun foo(bar: suspend () -> String) {
launch(CommonPool) { println(bar.invoke()) }
}
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おさらい
Kotlinはメソッドの最後の引数が関数の場合、カッコの外に書ける
上と下のhogeメソッド呼び出しは一緒の意味
hoge(1, { })
hoge(1) {
}
fun hoge(foo: Int, bar: () -> Unit) {
}
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おさらい
第二引数はデフォルト引数が設定されているので、
呼び出し時に指定しなくても良い
public fun launch(
context: CoroutineContext,
start: CoroutineStart = CoroutineStart.DEFAULT,
block: suspend CoroutineScope.() -> Unit
): Job {
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さっき読めなかったやつ
foo({
delay(10, TimeUnit.SECONDS)
"CA.kt"
})
fun foo(bar: suspend () -> String) {
launch(CommonPool) { println(bar.invoke()) }
}
引数に取ったbar suspend関数を実行するコルーチンを
良い感じのスレッドで実行して結果を出力
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Example 1
suspend fun foo(): String {
println("---foo--- : ${Thread.currentThread().name}")
delay(3, TimeUnit.SECONDS)
return "CA.kt"
}
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Example 1-1
fun main() {
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
println(foo())
println("----2---- : ${Thread.currentThread().name}")
}
println("----3---- : ${Thread.currentThread().name}”)
}
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Example 1-1
----0---- : main
----3---- : main
----1---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-1
CA.kt
----2---- : ForkJoinPool.commonPool-worker-1
fun main() {
println("----0----- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1----- : ${Thread.currentThread().name}")
println(foo())
println("----2----- : ${Thread.currentThread().name}")
}
println("----3----- : ${Thread.currentThread().name}”)
}
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Example 1-1
----0---- : main
----3---- : main
----1---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-1
CA.kt
----2---- : ForkJoinPool.commonPool-worker-1
※ Threadの数字は実行環境によって変わるので、気にしなくても大丈夫です
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Example 1-2
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
println(foo.await())
println("----3---- : ${Thread.currentThread().name}")
}
println("----4---- : ${Thread.currentThread().name}")
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Example 1-2
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
println(foo.await())
println("----3---- : ${Thread.currentThread().name}")
}
println("----4---- : ${Thread.currentThread().name}")
Deferred.await() => 実行を中断して値を返すsuspend関数
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Example 1-2
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
println(foo.await())
println("----3---- : ${Thread.currentThread().name}")
}
println("----4---- : ${Thread.currentThread().name}")
----0---- : main
----4---- : main
----1---- : ForkJoinPool.commonPool-worker-1
----2---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-1
CA.kt
----3---- : ForkJoinPool.commonPool-worker-1
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Example 1-3
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
foo.join()
println("----3---- : ${Thread.currentThread().name}")
println(foo.getCompleted())
println("----4---- : ${Thread.currentThread().name}")
}
println("----5---- : ${Thread.currentThread().name}")
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Example 1-3
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
foo.join()
println("----3---- : ${Thread.currentThread().name}")
println(foo.getCompleted())
println("----4---- : ${Thread.currentThread().name}")
}
println("----5---- : ${Thread.currentThread().name}")
Job.join() => await同様coroutineの実行完了まで待つが戻り値が無い
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Example 1-3
----0---- : main
----5---- : main
----1---- : ForkJoinPool.commonPool-worker-1
----2---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-2
----3---- : ForkJoinPool.commonPool-worker-1
CA.kt
----4---- : ForkJoinPool.commonPool-worker-1
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
foo.join()
println("----3---- : ${Thread.currentThread().name}")
println(foo.getCompleted())
println("----4---- : ${Thread.currentThread().name}")
}
println("----5---- : ${Thread.currentThread().name}")
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Example 2
suspend fun foo(): String {
println("---foo--- : ${Thread.currentThread().name}")
delay(6, TimeUnit.SECONDS)
return "foo"
}
suspend fun bar(): String {
println("---bar--- : ${Thread.currentThread().name}")
delay(3, TimeUnit.SECONDS)
return "bar"
}
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Example 2-1
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }.await()
println("----2---- : ${Thread.currentThread().name}")
val bar = async(CommonPool) { bar() }.await()
println("----3---- : ${Thread.currentThread().name}")
println(foo)
println("----4---- : ${Thread.currentThread().name}")
println(bar)
println("----5---- : ${Thread.currentThread().name}")
}
println("----6---- : ${Thread.currentThread().name}")
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Example 2-1
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }.await()
println("----2---- : ${Thread.currentThread().name}")
val bar = async(CommonPool) { bar() }.await()
println("----3---- : ${Thread.currentThread().name}")
println(foo)
println("----4---- : ${Thread.currentThread().name}")
println(bar)
println("----5---- : ${Thread.currentThread().name}")
}
println("----6---- : ${Thread.currentThread().name}")
----0---- : main
----6---- : main
----1---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-2
----2---- : ForkJoinPool.commonPool-worker-1
---bar--- : ForkJoinPool.commonPool-worker-1
----3---- : ForkJoinPool.commonPool-worker-1
foo
----4---- : ForkJoinPool.commonPool-worker-1
bar
----5---- : ForkJoinPool.commonPool-worker-1
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Example 2-1
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }.await()
println("----2---- : ${Thread.currentThread().name}")
val bar = async(CommonPool) { bar() }.await()
println("----3---- : ${Thread.currentThread().name}")
println(foo)
println("----4---- : ${Thread.currentThread().name}")
println(bar)
println("----5---- : ${Thread.currentThread().name}")
}
println("----6---- : ${Thread.currentThread().name}")
----0---- : main
----6---- : main
----1---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-1
----2---- : ForkJoinPool.commonPool-worker-1
---bar--- : ForkJoinPool.commonPool-worker-1
----3---- : ForkJoinPool.commonPool-worker-1
foo
----4---- : ForkJoinPool.commonPool-worker-1
bar
----5---- : ForkJoinPool.commonPool-worker-1
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Example 2-2
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
val bar = async(CommonPool) { bar() }
println("----3---- : ${Thread.currentThread().name}")
println(foo.await())
println("----4---- : ${Thread.currentThread().name}")
println(bar.await())
println("----5---- : ${Thread.currentThread().name}")
}
println("----6---- : ${Thread.currentThread().name}")
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Example 2-2
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
val bar = async(CommonPool) { bar() }
println("----3---- : ${Thread.currentThread().name}")
println(foo.await())
println("----4---- : ${Thread.currentThread().name}")
println(bar.await())
println("----5---- : ${Thread.currentThread().name}")
}
println("----6---- : ${Thread.currentThread().name}")
----0---- : main
----6---- : main
----1---- : ForkJoinPool.commonPool-worker-1
----2---- : ForkJoinPool.commonPool-worker-1
----3---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-2
---bar--- : ForkJoinPool.commonPool-worker-1
foo
----4---- : ForkJoinPool.commonPool-worker-1
bar
----5---- : ForkJoinPool.commonPool-worker-1
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Example 2-2
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) { foo() }
println("----2---- : ${Thread.currentThread().name}")
val bar = async(CommonPool) { bar() }
println("----3---- : ${Thread.currentThread().name}")
println(foo.await())
println("----4---- : ${Thread.currentThread().name}")
println(bar.await())
println("----5---- : ${Thread.currentThread().name}")
}
println("----6---- : ${Thread.currentThread().name}")
----0---- : main
----6---- : main
----1---- : ForkJoinPool.commonPool-worker-1
----2---- : ForkJoinPool.commonPool-worker-1
----3---- : ForkJoinPool.commonPool-worker-1
---foo--- : ForkJoinPool.commonPool-worker-2
---bar--- : ForkJoinPool.commonPool-worker-1
foo
----4---- : ForkJoinPool.commonPool-worker-1
bar
----5---- : ForkJoinPool.commonPool-worker-1
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Example 3 @Android
Clickしたら3秒後にtext viewにCA.ktをsetする
val button: Button
val textView: TextView
suspend fun foo(): String {
delay(3, TimeUnit.SECONDS)
return "CA.kt"
}
fun main() {
button.setOnClickListener {
launch(CommonPool) {
textView.text = foo()
}
}
}
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Example 3 @Android
Only the original thread that created a view hierarchy can touch its views.
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Example 3 @Android
Main thread以外でViewの更新は出来ない
val button: Button
val textView: TextView
suspend fun foo(): String {
delay(3, TimeUnit.SECONDS)
return "CA.kt"
}
fun main() {
button.setOnClickListener {
launch(CommonPool) {
textView.text = foo()
}
}
}
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Example 3 @Android
// for core
compile “org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinCoroutinesVersion”
// for JDK8
compile “org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:$kotlinCoroutinesVersion”
// for Asynchronous IO on JDK7+
compile “org.jetbrains.kotlinx:kotlinx-coroutines-nio:$kotlinCoroutinesVersion"
// for RxJava2
compile “org.jetbrains.kotlinx:kotlinx-coroutines-rx2:$kotlinCoroutinesVersion"
// for Android
compile “org.jetbrains.kotlinx:kotlinx-coroutines-android:$kotlinCoroutinesVersion"
// for Swing
compile “org.jetbrains.kotlinx:kotlinx-coroutines-swing:$kotlinCoroutinesVersion"
// for JavaFX
compile “org.jetbrains.kotlinx:kotlinx-coroutines-javafx:$kotlinCoroutinesVersion"
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Example 3 @Android
val UI = HandlerContext(Handler(Looper.getMainLooper()), "UI")
fun Handler.asCoroutineDispatcher() = HandlerContext(this)
public class HandlerContext(private val handler: Handler, private val name: String? = null) : CoroutineDispatcher(), Delay {
override fun dispatch(context: CoroutineContext, block: Runnable) {
handler.post(block)
}
override fun scheduleResumeAfterDelay(time: Long, unit: TimeUnit, continuation: CancellableContinuation) {
handler.postDelayed({
with(continuation) { resumeUndispatched(Unit) }
}, unit.toMillis(time))
}
override fun invokeOnTimeout(time: Long, unit: TimeUnit, block: Runnable): DisposableHandle {
handler.postDelayed(block, unit.toMillis(time))
return object : DisposableHandle {
override fun dispose() {
handler.removeCallbacks(block)
}
}
}
override fun toString() = name ?: handler.toString()
override fun equals(other: Any?): Boolean = other is HandlerContext && other.handler === handler
override fun hashCode(): Int = System.identityHashCode(handler)
}
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Example 3 @Android
val button: Button
val textView: TextView
suspend fun foo(): String {
delay(3, TimeUnit.SECONDS)
return "CA.kt"
}
fun main() {
button.setOnClickListener {
launch(UI) {
textView.text = foo()
}
}
}
Coroutine contextの引数をUIに置き換えると想定通りの動作
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Example 4 @RxJava
RxJavaのBehaviorProcessorにある値を取得して出力
val fooProcessor = BehaviorProcessor.createDefault("CA.kt")
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) {
fooProcessor
.doOnNext { println("----2---- : ${Thread.currentThread().name}") }
.awaitFirst()
}
println("----3---- : ${Thread.currentThread().name}")
println(foo.await())
println("----4---- : ${Thread.currentThread().name}”)
}
println("----5---- : ${Thread.currentThread().name}")
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Example 4 @RxJava
awaitFirst() => Rxのstreamからthreadをblockせずに
値をとってくるsuspend関数
val fooProcessor = BehaviorProcessor.createDefault("CA.kt")
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) {
fooProcessor
.doOnNext { println("----2---- : ${Thread.currentThread().name}") }
.awaitFirst()
}
println("----3---- : ${Thread.currentThread().name}")
println(foo.await())
println("----4---- : ${Thread.currentThread().name}")
}
println("----5---- : ${Thread.currentThread().name}")
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Example 4 @RxJava
----0---- : main
----5---- : main
----1---- : ForkJoinPool.commonPool-worker-1
----3---- : ForkJoinPool.commonPool-worker-1
----2---- : ForkJoinPool.commonPool-worker-2
CA.kt
----4---- : ForkJoinPool.commonPool-worker-1
val fooProcessor = BehaviorProcessor.createDefault("CA.kt")
println("----0---- : ${Thread.currentThread().name}")
launch(CommonPool) {
println("----1---- : ${Thread.currentThread().name}")
val foo = async(CommonPool) {
fooProcessor
.doOnNext { println("----2---- : ${Thread.currentThread().name}") }
.awaitFirst()
}
println("----3---- : ${Thread.currentThread().name}")
println(foo.await())
println("----4---- : ${Thread.currentThread().name}”)
}
println("----5---- : ${Thread.currentThread().name}")
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Conclusion
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Conclusion
• 結構手軽に非同期処理がかける
• 既存のRxを置き換える必要はない
FRESH!ではFluxのStoreから取得する場面によって使い分けている
• 今回は話していないChannelも使いこなせると より便利
• Experimentalなので、まだ注意が必要
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時間あったら
• GCはどうなってるか
• Bytecodeだと同処理されているか
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Resource management and GC
fun sequenceOfLines(fileName: String) = buildSequence {
BufferedReader(FileReader(fileName)).use {
while (true) {
yield(it.readLine() ?: break)
}
}
}
fun main(args: Array) {
sequenceOfLines("examples/sequence/sequenceOfLines.kt")
.forEach(::println)
}
DGIUUQTHJUIVCDPN,PUMJOLPUMJODPSPVUJOFT
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Resource management and GC
• コルーチンの参照を失った場合でも最終的にはGCされる
=> GCによって収集されるまでファイルは開いたままになる
fun main(args: Array) {
sequenceOfLines(“examples/sequence/sequenceOfLines.kt")
.take(3)
.forEach(::println)
}
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Bytecode
• 2つの中断があるコルーチン
• 状態
A. 1つ目の中断の前
B. 1つ目の中断後
C. 2つ目の中断後
val a = a()
val y = foo(a).await() // suspension point #1
b()
val z = bar(a, y).await() // suspension point #2
c(z)
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class extends CoroutineImpl<...> implements Continuation {
// The current state of the state machine
int label = 0
// local variables of the coroutine
A a = null
Y y = null
void resume(Object data) {
if (label == 0) goto L0
if (label == 1) goto L1
if (label == 2) goto L2
else throw IllegalStateException()
L0:
// data is expected to be `null` at this invocation
a = a()
label = 1
data = foo(a).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L1:
// external code has resumed this coroutine passing the result of .await() as data
y = (Y) data
b()
label = 2
data = bar(a, y).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L2:
// external code has resumed this coroutine passing the result of .await() as data
Z z = (Z) data
c(z)
label = -1 // No more steps are allowed
return
}
}
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class extends CoroutineImpl<...> implements Continuation {
// The current state of the state machine
int label = 0
// local variables of the coroutine
A a = null
Y y = null
void resume(Object data) {
if (label == 0) goto L0
if (label == 1) goto L1
if (label == 2) goto L2
else throw IllegalStateException()
L0:
// data is expected to be `null` at this invocation
a = a()
label = 1
data = foo(a).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L1:
// external code has resumed this coroutine passing the result of .await() as data
y = (Y) data
b()
label = 2
data = bar(a, y).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L2:
// external code has resumed this coroutine passing the result of .await() as data
Z z = (Z) data
c(z)
label = -1 // No more steps are allowed
return
}
}
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class extends CoroutineImpl<...> implements Continuation {
// The current state of the state machine
int label = 0
// local variables of the coroutine
A a = null
Y y = null
void resume(Object data) {
if (label == 0) goto L0
if (label == 1) goto L1
if (label == 2) goto L2
else throw IllegalStateException()
L0:
// data is expected to be `null` at this invocation
a = a()
label = 1
data = foo(a).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L1:
// external code has resumed this coroutine passing the result of .await() as data
y = (Y) data
b()
label = 2
data = bar(a, y).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L2:
// external code has resumed this coroutine passing the result of .await() as data
Z z = (Z) data
c(z)
label = -1 // No more steps are allowed
return
}
}
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class extends CoroutineImpl<...> implements Continuation {
// The current state of the state machine
int label = 0
// local variables of the coroutine
A a = null
Y y = null
void resume(Object data) {
if (label == 0) goto L0
if (label == 1) goto L1
if (label == 2) goto L2
else throw IllegalStateException()
L0:
// data is expected to be `null` at this invocation
a = a()
label = 1
data = foo(a).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L1:
// external code has resumed this coroutine passing the result of .await() as data
y = (Y) data
b()
label = 2
data = bar(a, y).await(this) // 'this' is passed as a continuation
if (data == COROUTINE_SUSPENDED) return // return if await had suspended execution
L2:
// external code has resumed this coroutine passing the result of .await() as data
Z z = (Z) data
c(z)
label = -1 // No more steps are allowed
return
}
}