integration/kotlinx-coroutines-jdk8/test/examples/simple-example-3.kt


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

package kotlinx.coroutines.examples

import kotlinx.coroutines.*
import kotlinx.coroutines.future.*
import java.util.concurrent.*

fun main(args: Array<String>) {
    // this example shows how easy it is to perform multiple async operations with coroutines
    val future = GlobalScope.future {
        (1..5).map { // loops are no problem at all
            startLongAsyncOperation(it).await() // suspend while the long method is running
        }.joinToString("\n")
    }
    println("We have a long-running computation in background, let's wait for its result...")
    println(future.get())
}

fun startLongAsyncOperation(num: Int): CompletableFuture<String> =
    CompletableFuture.supplyAsync {
        Thread.sleep(1000L) // imitate some long-running computation, actually
        "$num" // and return a number converted to string
}