example.kt

import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import kotlinx.coroutines.runBlocking
import java.util.concurrent.Executors
import java.util.concurrent.atomic.AtomicInteger
import kotlin.concurrent.thread
import kotlin.system.measureTimeMillis

val n = 100
val delay = 1000L

fun calcPool() {
  val int = AtomicInteger(0)
  val executor = Executors.newWorkStealingPool()

  val jobs = List(n) {
    executor.submit {
      Thread.sleep(delay)
      int.incrementAndGet()
    }
  }
  jobs.forEach { it.get() }
  println("Pool: ${int.get()}")
}

fun calcThreads() {
  val int = AtomicInteger(0)

  val jobs = List(n) {
    thread {
      Thread.sleep(delay)
      int.incrementAndGet()
    }
  }
  jobs.forEach { it.join() }
  println("Threads: ${int.get()}")
}

fun calcCoroutines() = runBlocking {
  val int = AtomicInteger(0)

  val jobs = List(n) {
    launch {
      delay(delay)
      int.incrementAndGet()
    }
  }
  jobs.forEach { it.join() }
  println("Coroutines: ${int.get()}")
}

fun main(args: Array<String>) {
  val coroutinesTotal = measureTimeMillis {
    calcCoroutines()
  }
  println("Time: $coroutinesTotal")
  println()

  val threadsTotal = measureTimeMillis {
    calcThreads()
  }
  println("Time: $threadsTotal")
  println()

  val poolTotal = measureTimeMillis {
    calcPool()
  }
  println("Time: $poolTotal")
  println()
}