Hands-On Object-Oriented Programming with Kotlin

Channels

The Deferred class, which was touched upon in the Parallel executing section, can be used to compute a single value. If we need to deal with a sequence of values, we can use channels. The Channel class contains the send and receive methods, which can be used in the following way:

fun main(args: Array<String>) = runBlocking<Unit> {    val channel = Channel<Int>()    launch {        for (x in 1..50) channel.send(x * x)    }    repeat(50) {        delay(500)        println(channel.receive())    }    println("Done!")}

Channels also allow us to transfer values from one coroutine to another safely in a multithreaded environment.