I want to call a method that makes an API call which is triggered by user interaction but I want to ...

# getting-started

[egek]

I want to call a method that makes an API call which is triggered by user interaction but I want to prevent it to get called multiple times if it hasn't been 1 minute yet, what would be the best way to do this?

[Klitos Kyriacou]

In Java, you could use RateLimiter from Guava (similar utilities are also available in some other libraries). You can use it in Kotlin too, but I don't know of any existing Kotlin-specific ones, especially any that play nicely with coroutines.

[Grégory Lureau]

class Debouncer(private val timeProvider: TimeProvider, private val durationMs: Long) {
    private var lastTimestamp: Long = Long.MIN_VALUE

    fun throttleFirst(block: () -> Unit) {
        val now = timeProvider.nowMs() // You could also remove the TimeProvider and just call System.currentTimeMillis(), just a bit easier to unit-test that way
        if (lastTimestamp + durationMs < now) {
            block()
            lastTimestamp = now
        }
    }
}

You don't really need a lib for something that simple IMO, and to use it

class MyClass {
    private val uiDebouncer = Debouncer(...)
    fun onUiClicked() {
        uiDebouncer.throttleFirst {
            doHeavyStuff()
        }
    }
}

I mean there is tons of libs like Guava, Rx and more that will adds a lot of functionnalities, but that's not super complex to write and adding a library means being dependent, choose wisely 😉