RxPlayground.kt

package br.com.gabryel.playground.rx

import io.reactivex.Observable
import io.reactivex.rxkotlin.toObservable
import io.reactivex.rxkotlin.zipWith
import java.time.LocalTime
import java.util.concurrent.TimeUnit
import kotlin.math.pow

fun main() {
    val list = listOf("a", "b", "c")
    val sleepMilli = 1000L

    rxWay(list, sleepMilli)
    listWay(list, sleepMilli)
    sequenceWay(list, sleepMilli)
}

private fun rxWay(list: List<String>, sleepMilli: Long) {
    val time = LocalTime.now()
    printValues("RX") {
        Observable
            .interval(sleepMilli, TimeUnit.MILLISECONDS)
            .zipWith(list.toObservable())
            .doOnNext { event ->
                println("Requesting $event: ${getTimeDifference(time)}")
            }.doOnNext { event ->
                println("Saving DB $event: ${getTimeDifference(time)}")
                Thread.sleep(600)
            }.doOnComplete {
                println("Finishing: ${getTimeDifference(time)}")
            }.subscribe()

        Thread.sleep(10000)
    }
}

private fun listWay(list: List<String>, sleepMilli: Long) {
    val time = LocalTime.now()
    printValues("LIST") {
        list.map { event ->
            println("Requesting $event: ${getTimeDifference(time)}")
            Thread.sleep(sleepMilli)
        }.forEach { event ->
            println("Saving DB $event: ${getTimeDifference(time)}")
            Thread.sleep(600)
        }

        println("Finishing: ${getTimeDifference(time)}")
    }
}

private fun sequenceWay(list: List<String>, sleepMilli: Long) {
    val time = LocalTime.now()
    printValues("SEQUENCE") {
        list.asSequence().map { event ->
            println("Requesting $event: ${getTimeDifference(time)}")
            Thread.sleep(sleepMilli)
        }.forEach { event ->
            println("Saving DB $event: ${getTimeDifference(time)}")
            Thread.sleep(600)
        }

        println("Finishing: ${getTimeDifference(time)}")
    }
}

private fun printValues(type: String, block: () -> Unit) {
    println()
    println("---- $type ----")
    block()
    println("---- $type ----")
    println()
}

private fun getTimeDifference(time: LocalTime) =
    (LocalTime.now().toNanoOfDay() - time.toNanoOfDay()) / 10.toDouble().pow(6.toDouble())