Hands-On Design Patterns with Kotlin

Buffered channels

Up until now, all the channels that we used had a capacity of exactly one element.

This means that if you write to this channel but no one reads from it, the sender will be suspended:

val channel = Channel<Int>()val j = launch {    for (i in 1..10) {        channel.send(i)        println("Sent $i")

    }}j.join()

This code doesn't print anything because the coroutine is waiting for someone to read from the channel.

To avoid that, we can create a buffered channel:

val channel = Channel<Int>(5)

Now suspension will occur only when the channel capacity is reached.

It prints:

Sent 1Sent 2Sent 3Sent 4Sent 5

Since produce() and actor() are also backed up by a channel, we can make it buffered too:

val actor = actor<Int>(capacity = 5) {    ...}val producer ...