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📖 13.1 API에서 DSL로: 표현력이 좋은 커스텀 코드 구조 만들기

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일반 구문간결한 구문사용한 언어 특성
StringUtil.capitalizes(s)s.capitalize()확장 함수
1.to(\"one\")1 to \"one\"중위 호출
set.add(2)set += 2연산자 오버로딩
map.get(\"key\")map[\"key\"]get 메소드에 대한 관례
file.use({ f -> f.read() })file.use { it.read() }람다를 괄호 밖으로 빼내는 관례
sb.append(\"yes\")with(sb) { append(\"yes\") append(\"no\") }수신 객체 지정 람다
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🔖 13.1.1 도메인 특화 언어

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🔖 13.1.2 내부 DSL은 프로그램의 나머지 부분과 매끄럽게 통합된다

\n\n\n SELECT country.name, COUNT(customer.id)\nFROM country\n JOIN customer ON customer.country_id = country.id\nGROUP BY country.name\nORDER BY COUNT(customer.id) DESC LIMIT 1;\n \n\n\n (Country innerJoin Customer)\n .slice(Country.name, Count(Customer.id))\n .selectAll()\n .groupBy(Country.name)\n .orderBy(Count(Customer.id), order = SortOrder.DESC)\n .limit(1)\n \n\n

🔖 13.1.3 DSL의 구조

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🔖 13.1.4 내부 DSL로 HTML 만들기

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📖 13.2 구조화된 API 구축: DSL에서 수신 객체 지정 람다 사용

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🔖 13.2.1 수신 객체 지정 람다와 확장 함수 타입

\n\n fun buildString(\n builderAction: (StringBuilder) -> Unit\n): String {\n val sb = StringBuilder()\n builderAction(sb)\n return sb.toString()\n}\n\nfun main() {\n val s = buildString {\n it.append("Hello, ")\n it.append("World!")\n }\n println(s)\n}\n \n\n\n fun buildString(\n builderAction: StringBuilder.() -> Unit\n): String {\n val sb = StringBuilder()\n sb.builderAction()\n return sb.toString()\n}\n\nfun main() {\n val s = buildString {\n this.append("Hello, ")\n this.append("World!")\n }\n println(s)\n}\n \n\n\n val appendExcl: StringBuilder.() -> Unit =\n { this.append("!") }\n\n\nfun main() {\n val stringBuilder = StringBuilder("Hi")\n stringBuilder.appendExcl()\n println(stringBuilder)\n println(buildString(appendExcl))\n}\n \n\n\n fun builderString(builderAction: StringBuilder.() -> Unit): String =\n StringBuilder().apply(builderAction).toString()\n \n\n

🔖 13.2.2 수신 객체 지정 람다를 HTML 빌더 안에서 사용

\n\n\n fun createSimpleTable() = createHTML().table {\n tr {\n td { +"cell" }\n }\n}\n \n\n\n open class Tag\n\nclass TABLE : Tag {\n fun tr(init: TR.() -> Unit)\n}\n\nclass TR : Tag {\n fun td(init: TD.() -> Unit)\n}\n\nclass TD : Tag\n \n\n\n fun createSimpleTable() = createHTML().table {\n this@table.tr {\n (this@tr).td {\n +"cell"\n }\n }\n}\n \n\n\n @DslMarker\nannotation class HtmlTagMarker\n \n\n\n @DslMarker\nannotation class HtmlTagMarker\n\n@HtmlTagMarker\nopen class Tag(val name: String) {\n private val children = mutableListOf<Tag>()\n\n protected fun <T : Tag> doInit(child: T, init: T.() -> Unit) {\n child.init()\n children.add(child)\n }\n\n override fun toString() = "<$name>${children.joinToString("")}</$name>"\n}\n\nfun table(init: TABLE.() -> Unit) = TABLE().apply(init)\n\nclass TABLE : Tag("table") {\n fun tr(init: TR.() -> Unit) = doInit(TR(), init)\n}\n\nclass TR : Tag("tr") {\n fun td(init: TD.() -> Unit) = doInit(TD(), init)\n}\n\nclass TD : Tag("td")\n\nfun createTable() = table {\n tr {\n td {\n }\n }\n}\n \n\n

🔖 13.2.3 코틀린 빌더: 추상화와 재사용을 가능하게 해준다

\n\n fun buildBookList() = createHTML().body {\n ul {\n li { a("#1") { +"The Three-Body Problem" } }\n li { a("#2") { +"The Cartesian Product Problem" } }\n li { a("#3") { +"The Conjugation Problem" } }\n }\n\n h2 { id = "1"; +"The Three-Body Problem" }\n p { +"The Three-Body Problem is a classic physics problem from the early 20th century." }\n\n h2 { id = "2"; +"The Cartesian Product Problem" }\n p { +"The Cartesian product is a useful mathematical construct for a wide variety of problems." }\n\n h2 { id = "3"; +"The Conjugation Problem" }\n p { +"The Conjugation Problem is a classic computational problem from the 1970s." }\n}\n \n\n\n fun buildBookList() = createHTML().body {\n listWithToc {\n item(\n "The Three-Body Problem",\n "The Three-Body Problem is a classic physics problem from the early 20th century."\n )\n item(\n "The Cartesian Product Problem",\n "The Cartesian product is a useful mathematical construct for a wide variety of problems."\n )\n item(\n "The Conjugation Problem",\n "The Conjugation Problem is a classic computational problem from the 1970s."\n )\n\n }\n}\n \n\n @HtmlTagMarker\nclass LISTWITHTOC {\n val entries = mutableListOf<Pair<String, String>>()\n fun item(headline: String, body: String) {\n entries += headline to body\n }\n}\n \n\n\n fun BODY.listWithToc(block: LISTWITHTOC.() -> Unit) {\n val listWithToc = LISTWITHTOC()\n listWithToc.block()\n ul {\n for ((index, entry) in listWithToc.entries.withIndex()) {\n li {\n a("#${index}") { +entry.first }\n }\n }\n }\n for ((index, entry) in listWithToc.entries.withIndex()) {\n h2 { id = "$index"; +entry.first }\n p { +entry.second }\n }\n}\n \n\n

📖 13.3 invoke 관례를 사용해 더 유연하게 블록 내포시키기

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🔖 13.3.1 invoke 관례를 사용해 더 유연하게 블록 내포시키기

\n\n class Greeter(val greeting: String) {\n operator fun invoke(name: String) {\n println("$greeting, $name!")\n }\n}\n\nfun main() {\n val bavarianGreeter = Greeter("Servus")\n bavarianGreeter("Dmitry")\n}\n \n\n

🔖 13.3.2 DSL의 invoke 관례: 그레이들 의존관계 선언

\n\n dependencies {\n testImplementation(kotlin("test"))\n implementation("org.jetbrains.exposed:exposed-core:0.40.1")\n implementation("org.jetbrains.exposed:exposed-dao:0.40.1")\n}\n \n\n\n dependencies.implementation("org.jetbrains.exposed:exposed-core:0.40.1")\n\ndependencies {\n implementation("org.jetbrains.exposed:exposed-core:0.40.1")\n}\n \n\n\n class DependencyHandler {\n fun implementation(coordinate: String) {\n println("Added dependency on $coordinate")\n }\n\n operator fun invoke(body: DependencyHandler.() -> Unit) {\n body()\n }\n}\n\nfun main() {\n val dependencies = DependencyHandler()\n dependencies.implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.0")\n dependencies {\n implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.5.0")\n }\n}\n \n\n

📖 13.4 실전 코틀린 DSL

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🔖 13.4.1 중위 호출 연쇄시키기: 테스트 프레임워크의 should 함수

\n\n class PrefixTest {\n @Test\n fun testKPrefix() {\n val s = "kotlin".uppercase()\n s should startWith("K")\n }\n}\n \n\n\n infix fun <T> T.should(matcher: Matcher<T>) = matcher.test(this)\n\ninterface Matcher<T> {\n fun test(value: T)\n}\n\nfun startWith(prefix: String): Matcher<String> {\n return object : Matcher<String> {\n override fun test(value: String) {\n if (!value.startsWith(prefix)) {\n throw AssertionError("$value does not start with $prefix")\n }\n }\n }\n}\n \n\n

🔖 13.4.2 원시 타입에 대해 확장 함수 정의하기: 날짜 처리

\n\n val Int.days: Duration\n get() = this.toDuration(DurationUnit.DAYS)\n\nval Int.hours: Duration\n get() = this.toDuration(DurationUnit.HOURS)\n \n\n

🔖 13.4.3 멤버 확장 함수: SQL을 위한 내부 DSL

\n","excerpt":"📖 13.1 API에서 DSL로: 표현력이 좋은 커스텀 코드 구조 만들기 일반 구문 간결한 구문 사용한 언어 특성 StringUtil.capitalizes(s) s.capitalize() 확장 함수 1.to(\"one\") 1 to \"one\" 중위 호출 set.add(2) set += 2 연산자 오버로딩 map.get(\"key\") map[\"key\"] get 메소드에 대한 관례 file.use({ f -> f.read() }) file.use { it.read…","fields":{"slug":"/backend/kotlin-in-action/13장-DSL_만들기/"},"frontmatter":{"title":"Kotlin in Action - 13장 DSL 만들기","thumbnail":{"childImageSharp":{"fluid":{"src":"/static/f7f7ddfa31d1614405dc5af1487b9ec4/9c94d/kotlin-in-action.png"}}},"draft":false,"category":"Back-End","tags":["Kotlin"],"date":"June 01, 2025"}},"previous":{"id":"368e41f3-7b7f-530b-b274-9dd74a426734","html":"

📖 15.1 코루틴 스코프가 코루틴 간의 구조를 확립한다

\n\n\n fun main() {\n runBlocking {\n launch {\n delay(1.seconds)\n launch {\n delay(250.milliseconds)\n log("Grandchild done")\n }\n log("Child 1 done!")\n }\n launch {\n delay(500.milliseconds)\n log("Child 2 done!")\n }\n log("Parent done!")\n }\n}\n \n\n 0 [main @coroutine#1] Parent done!\n524 [main @coroutine#3] Child 2 done!\n1020 [main @coroutine#2] Child 1 done!\n1275 [main @coroutine#4] Grandchild done\n \n\n

🔖 15.1.1 코루틴 스코프 생성: coroutineScope 함수

\n\n\n suspend fun generateValue(): Int {\n delay(500.milliseconds)\n return Random.nextInt(0, 10)\n}\n\nsuspend fun computeSum() {\n log("Computing a sum...")\n val sum = coroutineScope {\n val a = async { generateValue() }\n val b = async { generateValue() }\n a.await() + b.await()\n }\n log("Sum is $sum")\n}\n \n

🔖 15.1.2 코루틴 스코프를 컴포넌트와 연관시키기: CoroutineScope

\n\n\n class ComponentWithScope(dispatcher: CoroutineDispatcher = Dispatchers.Default) {\n private val scope = CoroutineScope(dispatcher + SupervisorJob())\n\n fun start() {\n log("Starting")\n scope.launch {\n while (true) {\n delay(500.milliseconds)\n log("Component working!")\n }\n }\n scope.launch {\n log("Doing a one-off task...")\n delay(500.milliseconds)\n log("Task done!")\n }\n }\n\n fun stop() {\n log("Stopping!")\n scope.cancel()\n }\n}\n \n\n

🔖 15.1.3 GlobalScope의 위험성

\n\n fun main() = runBlocking {\n GlobalScope.launch {\n delay(1000)\n launch {\n delay(250)\n log("Grandchild done")\n }\n log("Child 1 done!")\n }\n\n GlobalScope.launch {\n delay(500)\n log("Child 2 done!")\n }\n log("Parent done!")\n}\n \n\n 0 [main @coroutine#1] Parent done!\n \n\n

🔖 15.1.4 코루틴 콘텍스트와 구조화된 동시성

\n\n fun main() {\n runBlocking(Dispatchers.Default) {\n log(coroutineContext)\n launch {\n log(coroutineContext)\n launch(Dispatchers.IO + CoroutineName("mine")) {\n log(coroutineContext)\n }\n }\n }\n}\n \n\n 0 [DefaultDispatcher-worker-1 @coroutine#1] [CoroutineId(1), "coroutine#1":BlockingCoroutine{Active}@3a617b0f, Dispatchers.Default]\n13 [DefaultDispatcher-worker-2 @coroutine#2] [CoroutineId(2), "coroutine#2":StandaloneCoroutine{Active}@5e2dba97, Dispatchers.Default]\n14 [DefaultDispatcher-worker-3 @mine#3] [CoroutineName(mine), CoroutineId(3), "mine#3":StandaloneCoroutine{Active}@12764f6a, Dispatchers.IO]\n \n\n\n fun main() = runBlocking(CoroutineName("A")) {\n log("A's job: ${coroutineContext.job}")\n launch(CoroutineName("B")) {\n log("B's job: ${coroutineContext.job}")\n log("B's parent: ${coroutineContext.job.parent}")\n }\n log("A's children: ${coroutineContext.job.children.toList()}")\n}\n \n\n

📖 15.2 취소

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🔖 15.2.1 취소 촉발

\n\n fun main() = runBlocking {\n val launchedJob = launch {\n log("I'm launched!")\n delay(1000.milliseconds)\n log("I'm done!")\n }\n val asyncDeferred = async {\n log("I'm async")\n delay(1000.milliseconds)\n log("I'm done!")\n }\n delay(200.milliseconds)\n launchedJob.cancel()\n asyncDeferred.cancel()\n}\n \n\n 0 [main @coroutine#2] I'm launched!\n11 [main @coroutine#3] I'm async\n \n\n

🔖 15.2.2 시간제한이 초과된 후 자동으로 취소 호출

\n\n suspend fun calculateSomething(): Int {\n delay(3.seconds)\n return 2 + 2\n}\n\nfun main() = runBlocking {\n val quickResult = withTimeoutOrNull(500.milliseconds) {\n calculateSomething()\n }\n println(quickResult) // null\n val slowResult = withTimeoutOrNull(5.seconds) {\n calculateSomething()\n }\n println(slowResult) // 4\n}\n \n\n

🔖 15.2.3 취소는 모든 자식 코루틴에게 전파된다

\n\n fun main() = runBlocking {\n val job = launch {\n launch {\n launch {\n launch {\n log("I'm started")\n delay(500.milliseconds)\n log("I'm done!")\n }\n }\n }\n }\n delay(200.milliseconds)\n job.cancel()\n}\n \n\n

🔖 15.2.4 취소된 코루틴은 특별한 지점에서 CancellationException을 던진다

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🔖 15.2.5 취소는 협력적이다

\n\n suspend fun doCpuHeavyWork(): Int {\n log("I'm doing work!")\n var counter = 0\n val startTime = System.currentTimeMillis()\n while (System.currentTimeMillis() < startTime + 500) {\n counter++\n }\n return counter\n}\n\nfun main() = runBlocking {\n val myJob = launch {\n repeat(5) {\n doCpuHeavyWork()\n }\n }\n delay(600.milliseconds)\n myJob.cancel()\n}\n \n\n

🔖 15.2.6 코루틴이 취소됐는지 확인

\n\n val myJob = launch {\n repeat(5) {\n doCpuHeavyWork()\n if (!isActive) return@launch\n }\n}\n \n\n

🔖 15.2.7 다른 코루틴에게 기회를 주기: yield 함수

\n\n\n fun doCpuHeavyWork(): Int {\n var counter = 0\n val startTime = System.currentTimeMillis()\n while (System.currentTimeMillis() < startTime + 500) {\n counter++\n }\n return counter\n}\n\nfun main() {\n runBlocking {\n launch {\n repeat(3) {\n doCpuHeavyWork()\n }\n }\n launch {\n repeat(3) {\n doCpuHeavyWork()\n }\n }\n }\n}\n \n\n\n suspend fun doCpuHeavyWork(): Int {\n var counter = 0\n val startTime = System.currentTimeMillis()\n while (System.currentTimeMillis() < startTime + 500) {\n counter++\n yield()\n }\n return counter\n}\n\nfun main() {\n runBlocking {\n launch {\n repeat(3) {\n doCpuHeavyWork()\n }\n }\n launch {\n repeat(3) {\n doCpuHeavyWork()\n }\n }\n }\n}\n \n\n

🔖 15.2.8 리소스를 얻을 때 취소를 염두에 두기

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🔖 15.2.9 프레임워크가 여러분 대신 취소를 할 수 있다

\n","excerpt":"📖 15.1 코루틴 스코프가 코루틴 간의 구조를 확립한다 구조화된 동시성을 통해 각 코루틴은 코루틴 스코프에 속하게 된다. 다른 코루틴 빌더의 본문에서 launch나 async를 사용해 새로운 코루틴을 만들면 이 새로운 코루틴은 자동으로 해당 코루틴의 자식이 된다. 모든 자식 코루틴이 완료될 때까지 프로그램이 종료되지 않는다. 🔖 15.1.1 코루틴 스코프 생성: coroutineScope 함수 코루틴 빌더를 사용해 새로운 코루틴을 만들면 이 코루틴은 자체적인 CoroutineScope…","fields":{"slug":"/backend/kotlin-in-action/15장-구조화된_동시성/"},"frontmatter":{"title":"Kotlin in Action - 15장 구조화된 동시성","thumbnail":{"childImageSharp":{"fluid":{"src":"/static/f7f7ddfa31d1614405dc5af1487b9ec4/9c94d/kotlin-in-action.png"}}},"draft":false,"category":"Back-End","tags":["Kotlin"],"date":"June 15, 2025"}},"node":{"id":"86fd1f6e-8d93-5de7-b6c9-272ee6f10e07","html":"

📖 14.1 동시성과 병렬성

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📖 14.2 코틀린의 동시성 처리 방법: 일시 중단 함수와 코루틴

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📖 14.3 스레드와 코루틴 비교

\n\n\n fun main() {\n println("I'm on ${Thread.currentThread().name}")\n thread {\n println("And I'm on ${Thread.currentThread().name}")\n }\n}\n \n\n

코틀린은 스레드에 대한 대안으로 코루틴이라는 추상화를 도입

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📖 14.4 잠시 멈출 수 있는 함수: 일시 중단 함수

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🔖 14.4.1 일시 중단 함수를 사용한 코드는 순차적으로 보인다

\n\n fun login(credentials: Credentials): UserID\nfun loadUserData(userID: UserID): UserData\nfun showData(data: UserData)\n\nfun showUserInfo(credentials: Credentials) {\n val userID = login(credentials)\n val userData = loadUserData(userID)\n showData(userData)\n}\n \n\n\n suspend fun login(credentials: Credentials): UserID\nsuspend fun loadUserData(userID: UserID): UserData\nfun showData(data: UserData)\n\nfun showUserInfo(credentials: Credentials) {\n val userID = login(credentials)\n val userData = loadUserData(userID)\n showData(userData)\n}\n \n\n

📖 14.5 코루틴을 다른 접근 방법과 비교

\n\n fun loginAsync(credentials: Credentials, callback: (UserID) -> Unit) {}\nfun loadUserDataAsync(userID: UserID, callback: (UserData) -> Unit) {}\nfun showData(data: UserData) {}\n\nfun showUserInfo(credentials: Credentials) {\n loginAsync(credentials) { userID ->\n loadUserDataAsync(userID) { userData ->\n showData(userData)\n }\n }\n}\n \n\n\n fun loginAsync(credentials: Credentials): CompletableFuture<UserID>\nfun loadUserDataAsync(userID: UserID): CompletableFuture<UserData>\nfun showData(data: UserData)\n\nfun showUserInfo(credentials: Credentials) {\n loginAsync(credentials)\n .thenCompose { loadUserDataAsync(it) }\n .thenAccept { showData(it) }\n}\n \n\n\n fun login(credentials: Credentials): Single<UserID>\nfun loadUserData(userID: UserID): Single<UserData>\nfun showData(data: UserData)\n\nfun showUserInfo(credentials: Credentials) {\n login(credentials)\n .flatMap { loadUserData(it) }\n .doOnSuccess { showData(it) }\n .subscribe()\n}\n \n\n

위와 비교해보면 코루틴을 사용하는 접근 방식에서는 함수에 suspend 변경자만 추가하면 된다.

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🔖 14.5.1 일시 중단 함수 호출

\n\n\n suspend fun mySuspendingFunction() {}\n\nfun main() {\n mySuspendingFunction() // error\n}\n \n\n

📖 14.6 코루틴 세계로 들어가기: 코루틴 빌더

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🔖 14.6.1 일반 코드에서 코루틴의 세계로: runBlocking

\n\n suspend fun doSomethingSlowly() {\n delay(500.milliseconds)\n println("I'm done")\n}\n\nfun main() = runBlocking {\n doSomethingSlowly()\n}\n \n\n

🔖 14.6.2 발사 후 망각 코루틴 생성: launch 함수

\n\n private var zeroTime = System.currentTimeMillis()\nfun log(message: Any?) =\n println("${System.currentTimeMillis() - zeroTime} " + "[${Thread.currentThread().name}] $message")\n\nfun main() = runBlocking {\n log("The first, parent, coroutine starts")\n launch {\n log("The second coroutine starts and is ready to be suspended")\n delay(100.milliseconds)\n log("The second coroutine is resumed")\n }\n launch {\n log("The third coroutine can run in the meantime")\n }\n log("The first coroutine has launched two more coroutines")\n}\n \n\n\n 38 [main @coroutine#1] The first, parent, coroutine starts\n52 [main @coroutine#1] The first coroutine has launched two more coroutines\n53 [main @coroutine#2] The second coroutine starts and is ready to be suspended\n58 [main @coroutine#3] The third coroutine can run in the meantime\n163 [main @coroutine#2] The second coroutine is resumed\n \n\n

🔖 14.6.3 대기 가능한 연산: async 빌더

\n\n suspend fun slowlyAddNumbers(a: Int, b: Int): Int {\n log("Waiting a bit before calculating $a + $b")\n delay(100.milliseconds * a)\n return a + b\n}\n\nfun main() = runBlocking {\n log("Starting the async computation")\n val myFirstDeferred = async { slowlyAddNumbers(2, 2) }\n val mySecondDeferred = async { slowlyAddNumbers(4, 4) }\n log("Waiting for the deferred value to be available")\n log("The first result: ${myFirstDeferred.await()}")\n log("The second result: ${mySecondDeferred.await()}")\n}\n \n\n\n 44 [main @coroutine#1] Starting the async computation\n60 [main @coroutine#1] Waiting for the deferred value to be available\n65 [main @coroutine#2] Waiting a bit before calculating 2 + 2\n71 [main @coroutine#3] Waiting a bit before calculating 4 + 4\n287 [main @coroutine#1] The first result: 4\n481 [main @coroutine#1] The second result: 8\n \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
빌더반환값쓰임새
runBlocking람다가 계산한 값블로킹 코드와 넌블로킹 코드 사이를 연결
launchJob발사 후 망각 코루틴 시작(부수 효과가 있음)
asyncDeferred<T>값을 비동기로 계산(값을 기다릴 수 있음)
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📖 14.7 어디서 코드를 실행할지 정하기: 디스패처

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🔖 14.7.1 디스패처 선택

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🛠️ 다중 스레드를 사용하는 범용 디스패처: Dispatchers.Default

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🛠️ UI 스레드에서 실행: Dispatchers.Main

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🛠️ 블로킹되는 IO 작업 처리: Dispatchers.IO

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
디스패처스레드 개수쓰임새
Dispatchers.DefaultCPU 코어 수일반적인 연산, CPU 집약적인 작업
Dispatchers.Main1UI 프레임워크의 맥락에서만 작업
Dispatchers.IO64 + CPU 코어 개수(단, 최대 64개만 병렬 실행)블로킹 IO 작업, 네트워크 작업, 파일 작업
Dispatchers.Unconfined아무 스레드나즉시 스케줄링해야 하는 특별한 경우
limitedParallelism(n)커스텀(n)커스텀 시나리오
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🔖 14.7.2 코루틴 빌더에 디스패처 전달

\n\n fun main() {\n runBlocking {\n log("Doing some work")\n launch(Dispatchers.Default) {\n log("Doing some background work")\n }\n }\n}\n \n\n\n 45 [main @coroutine#1] Doing some work\n63 [DefaultDispatcher-worker-2 @coroutine#2] Doing some background work\n \n

🔖 14.7.3 withContext를 사용해 코루틴 안에서 디스패처 바꾸기

\n\n launch(Dispatchers.Default) {\n val result = performBackgroundOperation()\n withContext(Dispatchers.Main) {\n updateUI(result)\n }\n}\n \n\n

🔖 14.7.4 코루틴과 디스패처는 스레드 안전성 문제에 대한 마법 같은 해결책이 아니다

\n\n fun main() {\n runBlocking {\n launch(Dispatchers.Default) {\n var x = 0\n repeat(10_000) {\n x++\n }\n println(x)\n }\n }\n}\n \n\n\n fun main() {\n runBlocking {\n var x = 0\n repeat(10_000) {\n launch(Dispatchers.Default) {\n x++\n }\n }\n delay(1.seconds)\n println(x)\n }\n}\n \n\n\n fun main() = runBlocking {\n val mutex = Mutex()\n var x = 0\n repeat(10_000) {\n launch(Dispatchers.Default) {\n mutex.withLock {\n x++\n }\n }\n }\n delay(1.seconds)\n println(x)\n}\n \n\n

📖 14.8 코루틴은 코루틴 콘텍스트에 추가적인 정보를 담고 있다

\n\n\n suspend fun introspect() {\n log(coroutineContext)\n}\n\nfun main() {\n runBlocking {\n introspect()\n }\n}\n \n\n\n 39 [main @coroutine#1] [CoroutineId(1), "coroutine#1":BlockingCoroutine{Active}@32709393, BlockingEventLoop@3d99d22e]\n \n\n fun main() {\n runBlocking(Dispatchers.IO + CoroutineName("Coolroutine")) {\n introspect()\n }\n}\n \n\n\n 43 [DefaultDispatcher-worker-1 @Coolroutine#1] [CoroutineName(Coolroutine), CoroutineId(1), "Coolroutine#1":BlockingCoroutine{Active}@1be729a6, Dispatchers.IO]\n ","excerpt":"📖 14.1 동시성과 병렬성 동시성 여러 작업을 동시에 실행하는 것 CPU 코어 하나에서 동시성 사용 가능 병렬성 코드를 여러 부분으로 나눠서 동시에 수행할 수 있는 능력 여러 CPU 코어에서 물리적으로 동시에 실행하는 것 📖 14.2 코틀린의 동시성 처리 방법: 일시 중단 함수와 코루틴 코루틴은 비동기적으로 실행되는 넌블로킹 동시성 코드를 우아하게 작성할 수 있게 해준다. 스레드에 비해 매우 가볍다. 동시성 작업과 생명주기 관리 기능 제공 📖 14.3 스레드와 코루틴 비교 JVM…","fields":{"slug":"/backend/kotlin-in-action/14장-코루틴/"},"frontmatter":{"title":"Kotlin in Action - 14장 코루틴","thumbnail":{"childImageSharp":{"fluid":{"src":"/static/f7f7ddfa31d1614405dc5af1487b9ec4/9c94d/kotlin-in-action.png"}}},"draft":false,"category":"Back-End","tags":["Kotlin"],"date":"June 08, 2025"}}}},"staticQueryHashes":["2374173507","2996537568","3691437124"]}