but the idea is to define it in the class so it can be a part of the api

but only within the scope of the function foo

edited it.. foo would be open/abstract

the closest you can get is having

help

protected

and

foo

open

, otherwise it should be in

foo

, like your first example

Yeah i figured. It would just be cool if that was possible. And it seems like since we have local functions that it wouldn’t be impossible

Hello

I am making a delegated property... I am really close to finishing it, but the return type (

Any

) is such that Kotlin can not recognize it as a delegate. Any way I can fix this?

inline fun <reified T : Any> ConfigurationSection.tester(
    basePath: String,
    default: T,
    crossinline accept: (T) -> Boolean = { true }
): Any {
    return object {
        operator fun getValue(thisRef: T, property: KProperty<*>): T {
            val camelCase = property.name.hyphenate()
            val path = "$basePath.$camelCase"
            val res = this@tester[path]

            return when (res) {
                null, !is T, !accept(res) -> {
                    this@tester[path] = default
                    default
                }
                else -> res
            }
        }
    }
}

Implement

ReadOnlyProperty

and return that type. https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.properties/-read-only-property/index.html

This is the bare bones version of an abstract factory I've designed from scratch. Is there a more idiomatic or efficient way of doing this? Posted in #getting-started

I'm trying to deseriliased a json into an object but I keep getting this error

Exception in thread "main" com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `Message` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator)
 at [Source: (String)"{"message": "foo"}"; line: 1, column: 2]
	at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63)
	at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1343)
	at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1032)
	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1297)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:326)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004)
	at UserRestServiceKt.main(UserRestService.kt:8)

my code

import com.fasterxml.jackson.databind.ObjectMapper

private val objectMapper = ObjectMapper()
fun main(args: Array<String>) {
    val someJson: String = """{"message": "foo"}"""
    val serialised = objectMapper.readValue(someJson, Message::class.java)
}

data class Message(val message: String)

here you go folks:

class GreetingProvider(_greeting: String) {
    val greeting = _greeting
}

class GreetingPrinter(private val _greetingProvider: GreetingProvider) {
    fun printGreeting() = println(_greetingProvider.greeting)
}

fun main(args: Array<String>) {
    val myBeans = beans {
        bean { GreetingProvider("Hello, there!") }
        bean { GreetingPrinter( ref<GreetingProvider>())}
    }

    val context = GenericApplicationContext()

    val xmlReader = XmlBeanDefinitionReader(context)
    xmlReader.loadBeanDefinitions(ClassPathResource("META-INF/some-context.xml"))

    context.refresh()
}

interesting/funny fact:

Array<*>::class

triggers the very same error

Behold, my magnum opus: https://youtrack.jetbrains.com/issue/KT-30221?project=kt This is a bewildering error that I just happened to stumble upon. It's pretty easy to work around, but I'm hoping it gets fixed anyway.

Hi! I'm trying to understand am I the only one having trouble with officially recommended directory structure. Summed up my question on reddit: https://www.reddit.com/r/Kotlin/comments/aw8xdb/do_you_use_officially_recommended_directory/

Ah Yes, Java Packages. it made you feels like you are digging a hole.

Yep, that's why I decided to switch to a new recommendation. But it has it's drawbacks (at least at the moment).

it is not "new recommendation" because it is the standard way of java projects do src/main/java/com/example/main.java

also is there a good way to write two extension functions for

Int

and

Long

(or likewise

Float

and

Double

) without repeating a bunch of code?

I am guessing that putting

@JvmField

on the x field might help. Can you try that and report back?

heey, i have a simple question but due to the keywords in it I cannot find the right answer on google

i need a field of type Class in my class

how do I do that?

val x: Class<MyType>

or

KClass<MyType>

@karelpeeters thank you, here is what worked:

lateinit var valueSerializer: Class<Serializer<Any>>

Untitled.kt

-.kt

Hey everyone 👋 I’m giving a lightning talk (10 mins!) to a couple of BE java engineers at work to introduce Kotlin to them and get them excited enough to go back and try Kotlin and in the best case, contribute Kt to the codebase. I need a list of a couple of language features and examples with code snippets which you think are really cool and exciting and make Kotlin way more preferrable to Java for BE development

Hey everyone! We’re organising a conference devoted to Kotlin in Kyiv. Here it is http://knightkyiv.com/ If you would like to join us as speaker here you can find a cfp link https://www.papercall.io/knight-kyiv

Hello. I guess

::ClassName

is a reference to the class constructor? Wrote it by accident, and seems handy…