第三章.ライフサイクルとエラー制御

ジョブとDeferred

Job

//job은 예외를 던진 곳까지 전파시킨다.
fun main(args : Array<String>) = runBlocking{
    val job = GlobalScope.launch {
        TODO("Not Implemented")
    }

    delay(2000L)   
}

ライフサイクル

作成(New)

fun main(args : Array<String>) = runBlocking{
    val job = GlobalScope.launch(start = CoroutineStart.LAZY) {
        TODO("Not Implemented")
    }
    delay(2000L)
}

アクティブ(Active)

fun main(args : Array<String>) : Unit = runBlocking{
    val job = GlobalScope.launch(start = CoroutineStart.LAZY) {
        delay(2000L)
        println("Complete")
    }
    job.join()
}

fun main(args : Array<String>) {
    val task = GlobalScope.launch {
        delay(1000L)
        println("Complete")
    }

    task.start()
}

キャンセル

//handler 처리 
fun main(args : Array<String>)  = runBlocking{
    val exceptionHandler = CoroutineExceptionHandler { _, throwable ->
        println("Job cancelled due to ${throwable.message}")
    }


    GlobalScope.launch(exceptionHandler) {
        TODO("Not implemented yet")
    }

    delay(2000L)
}

//invokeOnCompleteion 처리
fun main(args : Array<String>)  = runBlocking{

    GlobalScope.launch {
        TODO("Not implemented yet")
    }.invokeOnCompletion { cause ->
        cause?.run {
            println("Job Cancelled due to $this")
        }
    }

    delay(2000L)
}

完了

Deferred

//try-catch 문으로 예외 처리가 가능하다.
fun main(args : Array<String>) : Unit  = runBlocking{
    val deferred = GlobalScope.async {
        TODO("Not implemented yet")
    }

    try {
        deferred.await()
    }catch (e : Throwable){
        println("Deferred cancelled due to ${e.message}")
    }
}

//에러를 전파 받는 곳에 handler를 이용한다.
fun main(args: Array<String>): Unit = runBlocking {
    val exceptionHandler = CoroutineExceptionHandler{_, handler ->
        println("Defered cancelled due to ${handler.message}")
    }

    val deferred = GlobalScope.async {
        TODO("Not implemented yet")
    }

    GlobalScope.launch(exceptionHandler){
        deferred.await()
    }.join()
}

状態が一方向に動く

fun main(args: Array<String>): Unit = runBlocking {
    val task = measureTimeMillis {
        val job = GlobalScope.launch{
            delay(2000L)
        }

        job.join()

        //restart
        job.start()
        job.join()
    }

    println("Time: $task ms")
}

リファレンス