Kotlin协程flow的debounce与管道Channel

缺乏、安全感 2023-10-15 11:22 27阅读 0赞

### Kotlin协程flow的debounce与管道Channel ###

import kotlinx.coroutines.Dispatchers
    import kotlinx.coroutines.channels.Channel
    import kotlinx.coroutines.delay
    import kotlinx.coroutines.flow.*
    import kotlinx.coroutines.launch
    import kotlinx.coroutines.runBlocking
    
    const val timeOut = 150L
    val delayTimes = arrayListOf(50L, 100L, 150L, 200L, 250L)
    
    fun main(args: Array<String>) {
        val channel = Channel<String>()
    
        runBlocking {
            launch(Dispatchers.IO) {
                repeat(5) {
                    val t = System.currentTimeMillis()
                    println("待发射 $it $t ...")
                    channel.send("$it-$t")
    
                    val d = delayTimes.random() //从列表中随机选择一个延迟时间。
                    println("$it 休眠 $d")
                    delay(d)
                }
            }
    
            launch(Dispatchers.IO) {
                channel.receiveAsFlow().debounce(timeOut).collect {
                    println("debounce $it")
                }
            }
    
            println("runBlocking")
        }
    
        //channel.receiveAsFlow()将永恒处于接收状态，走不到channel.close()这里
        //channel.close()
    }

> 待发射 0 1693126278615 ...  
> runBlocking  
> 0 休眠 100  
> 待发射 1 1693126278746 ...  
> 1 休眠 50  
> 待发射 2 1693126278810 ...  
> 2 休眠 200  
> debounce 2-1693126278810  
> 待发射 3 1693126279011 ...  
> 3 休眠 50  
> 待发射 4 1693126279075 ...  
> 4 休眠 50  
> debounce 4-1693126279075

<dependency>
                <groupId>org.jetbrains.kotlinx</groupId>
                <artifactId>kotlinx-coroutines-core</artifactId>
                <version>1.7.3</version>
                <type>pom</type>
            </dependency>

[https://zhangphil.blog.csdn.net/article/details/131103698![icon-default.png?t=N7T8][icon-default.png_t_N7T8]https://zhangphil.blog.csdn.net/article/details/131103698][https_zhangphil.blog.csdn.net_article_details_131103698_icon-default.png_t_N7T8_icon-default.png_t_N7T8_https_zhangphil.blog.csdn.net_article_details_131103698]

[kotlin协程管道Channel\_zhangphil的博客-CSDN博客runBlocking 内部启动的3个协程做耗时操作，从输出可以看到3个协程交叉并发执行，runBlocking 会等到3个协程执行结束后才退出，输出结果有明确先后顺序。runBlocking 会等待相同作用域的协程完成才退出runBlocking 本身阻塞线程，但内部运行的协程又非阻塞。kotlin的runBlocking 当内部相同作用域的所有协程都运行结束后，在 runBlocking 之后的代码才能执行， runBlocking 会阻塞所在线程。kotlin协程管道Channel。![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/131096899][kotlin_Channel_zhangphil_-CSDN_runBlocking _3_3_runBlocking _3_runBlocking _runBlocking _kotlin_runBlocking _ runBlocking _ runBlocking _kotlin_Channel_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_131096899][Kotlin协程flow发送时间间隔debounce\_zhangphil的博客-CSDN博客debounce蕴含了一定的缓冲思想，即，不立刻触发事件，而是先把要发射的数据进入队列，稍等一定时间（时间）延迟触发，而触发的重要条件取决于前一条数据和后一条数据的时间间隔，注意，前一条和后一条尚未被发射出去，只是待命中。发射完ABC，Kotlin审视待发射的ABCD，按理说ABCD与ABC间隔200，满足发射timeOut值，但是ABCD与ABCDE间隔100，所以跳过ABCD，直接发射ABCDE。四、map，重组改写数据。A和AB都待发射，A和AB间隔100，所以跳过A，直接发射AB。![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/132515686][Kotlin_flow_debounce_zhangphil_-CSDN_debounce_ABC_Kotlin_ABCD_ABCD_ABC_200_timeOut_ABCD_ABCDE_100_ABCD_ABCDE_map_A_AB_A_AB_100_A_AB_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_132515686][kotlin协程接收管道ReceiveChannel生产者produce\_kotlin produce\_zhangphil的博客-CSDN博客runBlocking 内部启动的3个协程做耗时操作，从输出可以看到3个协程交叉并发执行，runBlocking 会等到3个协程执行结束后才退出，输出结果有明确先后顺序。runBlocking 会等待相同作用域的协程完成才退出runBlocking 本身阻塞线程，但内部运行的协程又非阻塞。kotlin的runBlocking 当内部相同作用域的所有协程都运行结束后，在 runBlocking 之后的代码才能执行， runBlocking 会阻塞所在线程。kotlin协程管道Channel。\_kotlin produce![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/131103072][kotlin_ReceiveChannel_produce_kotlin produce_zhangphil_-CSDN_runBlocking _3_3_runBlocking _3_runBlocking _runBlocking _kotlin_runBlocking _ runBlocking _ runBlocking _kotlin_Channel_kotlin produce_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_131103072]

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[Kotlin_flow_debounce_zhangphil_-CSDN_debounce_ABC_Kotlin_ABCD_ABCD_ABC_200_timeOut_ABCD_ABCDE_100_ABCD_ABCDE_map_A_AB_A_AB_100_A_AB_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_132515686]: https://blog.csdn.net/zhangphil/article/details/132515686
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