Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Test and prototype for a more specific back pressure in rxjava 2
package com.jaynewstrom.rx
import io.reactivex.Flowable
import io.reactivex.Scheduler
import io.reactivex.schedulers.Schedulers
import org.junit.Test
import java.util.concurrent.CountDownLatch
import java.util.concurrent.TimeUnit
import java.util.concurrent.atomic.AtomicLong
class RxBackPressure {
@Test fun yay() {
val atomicCount = AtomicLong()
val latch = CountDownLatch(500)
Flowable.interval(0, 50, TimeUnit.MILLISECONDS)
.map {
latch.countDown()
atomicCount.incrementAndGet()
}
.takeOnlyMostRecentEvents(Schedulers.io(), 50, TimeUnit.MILLISECONDS)
.map { count ->
if (count % 3 == 0L) {
Thread.sleep(30)
} else if (count % 2 == 0L) {
Thread.sleep(80)
} else {
Thread.sleep(200)
}
count
}.subscribe {
println("At position: $it - at: ${System.currentTimeMillis()} - on: ${Thread.currentThread().name}")
}
latch.await(1, TimeUnit.MINUTES)
}
}
fun <T> Flowable<T>.takeOnlyMostRecentEvents(
scheduler: Scheduler,
sourceEmisionInterval: Long,
sourceEmissionIntervalUnit: TimeUnit
): Flowable<T> {
val sourceEmissionIntervalMillis = TimeUnit.MILLISECONDS.convert(sourceEmisionInterval, sourceEmissionIntervalUnit)
return onBackpressureDrop()
.map { sourceEvent -> DataHolder(sourceEvent) }
.observeOn(scheduler)
.filter { it.isCurrent(sourceEmissionIntervalMillis) }
.map { it.sourceEvent }
}
private class DataHolder<T>(val sourceEvent: T, val emittedMillis: Long = System.currentTimeMillis()) {
fun isCurrent(sourceEmissionIntervalMillis: Long): Boolean {
val diff = System.currentTimeMillis() - emittedMillis
return diff < sourceEmissionIntervalMillis
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.
You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session.