JavalinApiExample.kt

import infrastructure.Json
import io.javalin.Javalin
import io.javalin.plugin.json.FromJsonMapper
import io.javalin.plugin.json.JavalinJson
import io.javalin.plugin.json.ToJsonMapper

sealed class Device {
    data class Laptop(val model: String) : Device()
    data class Phone(val model: String, val carrier: String): Device()
}

class Employee(val device: List<Device>)

fun main() {
    val app = Javalin.create().start(7000)

    JavalinJson.toJsonMapper = object : ToJsonMapper {
        override fun map(obj: Any): String = Json.toJson(obj)
    }
    JavalinJson.fromJsonMapper = object : FromJsonMapper {
        override fun <T> map(json: String, targetClass: Class<T>): T = Json.fromJsonWithClass(json, targetClass)
    }

    app.get("/") { ctx ->
        ctx.result("Hello, World!")
    }

    app.get("/device") { ctx ->
        val devices = listOf(Device.Laptop("Macbook Pro"), Device.Phone("IPhone", "T-Mobile"))
        ctx.json(Employee(devices))
    }
}