Simple Event Emitter for Kotlin

Event.kt

package dev.zihad.util

interface Event

EventEmitter.kt

package dev.zihad.util

import dev.zihad.sharedsharder.api.Event
import dev.zihad.sharedsharder.api.EventListener
import kotlin.reflect.KClass

open class EventEmitter {
  val listeners = mutableMapOf<KClass<out Event>, MutableList<EventListener<out Event>>>()

  fun <E : Event> emit(event: E) {
    listeners[event::class]?.filterIsInstance<EventListener<E>>()?.forEach { it.onEvent(event) }
  }

  inline fun <reified E : Event> on(listener: EventListener<E>) {
    val eventListeners = listeners.getOrPut(E::class) {
      mutableListOf()
    }
    eventListeners.add(listener)
  }
}

EventListener.kt

package dev.zihad.util

fun interface EventListener<E: Event> {
  fun onEvent(event: E)
}