example-sync-04.kt

/*
 * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */

// This file was automatically generated from coroutines-guide.md by Knit tool. Do not edit.
package kotlinx.coroutines.guide.sync04

import kotlinx.coroutines.*
import kotlin.system.*

suspend fun CoroutineScope.massiveRun(action: suspend () -> Unit) {
    val n = 100  // number of coroutines to launch
    val k = 1000 // times an action is repeated by each coroutine
    val time = measureTimeMillis {
        val jobs = List(n) {
            launch {
                repeat(k) { action() }
            }
        }
        jobs.forEach { it.join() }
    }
    println("Completed ${n * k} actions in $time ms")    
}

val counterContext = newSingleThreadContext("CounterContext")
var counter = 0

fun main() = runBlocking<Unit> {
//sampleStart
    GlobalScope.massiveRun { // run each coroutine with DefaultDispathcer
        withContext(counterContext) { // but confine each increment to the single-threaded context
            counter++
        }
    }
    println("Counter = $counter")
//sampleEnd    
}