seald class sample

hoge.kt

package jp.co.hoge

import org.junit.Test

sealed class Event {
    class Loading : Event()
    class Loaded(val result: String) : Event()
    class LoadFailed(val reason: String) : Event()
}

class SampleTest {
    @Test
    fun sample() {
        val event1 = Event.Loading()
        val event2 = Event.Loaded("１です")
        val event3 = Event.LoadFailed("やんごとなき理由です")

        val events = listOf(event1, event2, event3)

        events.forEach { hoge(it) }
    }

    fun hoge(event: Event) {
        when (event) {
            is Event.Loading -> println("読み込み中です")
            is Event.Loaded -> println("こんな感じの結果です ${event.result}")
            is Event.LoadFailed -> println("残念ですが失敗しました ${event.reason}")
        }
    }
}