Kotlin协程flow瞬时密集数据流去重debounce（1）

Kotlin协程flow瞬时密集数据流去重debounce（1）

这个功能很像Android里面利用Handler发送一些列delay的message，然后再handleMessage里面，根据收到的前后时延是否大于某个值，如果大于等于，则处理，否则丢弃。

import kotlinx.coroutines.async
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.debounce
import kotlinx.coroutines.flow.flowOn
import kotlinx.coroutines.flow.onEach
import kotlinx.coroutines.flow.receiveAsFlow
import kotlinx.coroutines.newFixedThreadPoolContext
import kotlinx.coroutines.runBlocking

const val mTimeOut = 300L

val mChannel = Channel<Int>()
val mThreadPool = newFixedThreadPoolContext(nThreads = 4, name = "my-thread")

fun main() {
    val totalTaskSize = 20

    runBlocking {
        //接收任务
        async {
            mChannel.receiveAsFlow()
                .onEach { it ->  //生产者
                    println("onEach $it ${Thread.currentThread().name}")
                }.flowOn(mThreadPool)
                .debounce(mTimeOut)
                .collect { it -> //消费者
                    recv(it)
                }
        }

        //源源不断的密集发送加载任务。
        async(mThreadPool) {
            repeat(totalTaskSize) { it ->
                println("send $it ${Thread.currentThread().name}")
                mChannel.send(it)

                val t = (mTimeOut * Math.random()).toLong() + 100
                println("send $it over, delay=$t ${Thread.currentThread().name}")
                delay(t)
            }
        }
    }
}

private fun recv(n: Int) {
    runBlocking {
        async(mThreadPool) {
            println("collect $n ${Thread.currentThread().name}")
        }
    }
}

输出：

send 0 my-thread-1
onEach 0 my-thread-1
send 0 over, delay=276 my-thread-2
send 1 my-thread-3
send 1 over, delay=184 my-thread-3
onEach 1 my-thread-1
send 2 my-thread-4
send 2 over, delay=169 my-thread-4
onEach 2 my-thread-2
send 3 my-thread-3
send 3 over, delay=175 my-thread-3
onEach 3 my-thread-1
send 4 my-thread-4
send 4 over, delay=129 my-thread-4
onEach 4 my-thread-2
send 5 my-thread-2
send 5 over, delay=367 my-thread-2
onEach 5 my-thread-1
collect 5 my-thread-3
send 6 my-thread-2
send 6 over, delay=271 my-thread-2
onEach 6 my-thread-4
send 7 my-thread-1
send 7 over, delay=200 my-thread-1
onEach 7 my-thread-3
send 8 my-thread-2
send 8 over, delay=356 my-thread-2
onEach 8 my-thread-4
collect 8 my-thread-3
send 9 my-thread-2
send 9 over, delay=222 my-thread-2
onEach 9 my-thread-1
send 10 my-thread-4
send 10 over, delay=146 my-thread-4
onEach 10 my-thread-3
send 11 my-thread-2
send 11 over, delay=215 my-thread-2
onEach 11 my-thread-1
send 12 my-thread-2
send 12 over, delay=200 my-thread-2
onEach 12 my-thread-3
send 13 my-thread-1
send 13 over, delay=298 my-thread-1
onEach 13 my-thread-4
send 14 my-thread-2
send 14 over, delay=226 my-thread-2
onEach 14 my-thread-3
collect 13 my-thread-1
send 15 my-thread-2
send 15 over, delay=337 my-thread-2
onEach 15 my-thread-3
collect 15 my-thread-1
send 16 my-thread-2
send 16 over, delay=160 my-thread-2
onEach 16 my-thread-4
send 17 my-thread-2
send 17 over, delay=147 my-thread-2
onEach 17 my-thread-1
send 18 my-thread-3
send 18 over, delay=262 my-thread-3
onEach 18 my-thread-4
send 19 my-thread-2
send 19 over, delay=163 my-thread-2
onEach 19 my-thread-1
collect 19 my-thread-4

相关：

https://blog.youkuaiyun.com/zhangphil/article/details/132515686

https://blog.youkuaiyun.com/zhangphil/article/details/132525124