coroutie_channel6

channel

There are four types of channels

Unlimited channel , Buffered channel , Rendezvous channel , Conflated channel

Rendezvous channel

By default, a “Rendezvous” channel is created.

import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.*

fun main() = runBlocking<Unit> {
    val channel = Channel<String>()
    launch {
        channel.send("A1")
        channel.send("A2")
        log("A done")
    }
    launch {
        channel.send("B1")
        log("B done")
    }
    launch {
        repeat(3) {
            val x = channel.receive()
            log(x)
        }
    }
}

fun log(message: Any?) {
    println("[${Thread.currentThread().name}] $message")
}

Watch this video for a better understanding of channels.

https://www.youtube.com/watch?v=HpWQUoVURWQ

channel是并发安全的队列,队列一定存在缓冲区满了，并且没有人调用receive取走函数，send就挂起

82. produce与actor

83. 复用多个await

    多路复用

    网络和本地缓存获取数据，哪一个先返回就先用那个做展示

    fun CoroutineScope.getUserFromLocal() = async(Dispatchers.IO) {
        // 模拟读取本地数据
        delay(1000)
        "getUserFromLocal"
    }
    
    fun CoroutineScope.getUserFromNetwork() = async(Dispatchers.IO) {
        // 模拟读取网络数据
        delay(500)
        "getUserFromNetwork"
    }
    
    fun testSelectAwait() = runBlocking {
        GlobalScope.launch {
            val userFromLocal = getUserFromLocal()
            val userFromNetwork = getUserFromNetwork()
            val select = select<String> {
                userFromLocal.onAwait { it }
                userFromNetwork.onAwait { it }
            }
            println(select)
        }.join()
    }

https://kotlinlang.org/docs/coroutines-and-channels.html#channels