How to avoid ConcurrentModificationException in concurrent code when iterating Map's values? Any safe API for this?

what’s the best practices way to reference a class’s field dynamically by name? Use reflection?

Hi people! The CTO of our company is trying to convince our Android team to start prefixing all class names with a three letter uppercase abbreviation of the company’s name. E.g. Company name: Fancy Coffee Roasting Class name: FCRProfileViewModel He’s also an iOS developer, where prefixing seems more reasonable because of the global namespace pollution and conflicts that are caused by not requiring imports, if I’m not mistaken. It also seems more natural as it appears to be some legacy of Objective-C. Apart from the arguments of additional noise that comes with the three uppercase letters and that this pattern is quite uncommon for Kotlin, what would be your arguments against it? We’re also worried that this change will break some of the beauty our IDE supplies, like suggesting names, as variable names aren’t meant to include the prefix.

Hello people! I am having some troubles creating a thread pool. First of all, reference to projects for which i'm having problem: 1. https://github.com/Animeshz/threadpool (isn't completed yet, i.e. problem is in here) 2. https://github.com/Animeshz/promise (dependency, don't think so there's problem here but maybe co-related) the problem is that the code in the done block isn't executing always (like it executes sometime whereas sometime isn't). https://github.com/Animeshz/threadpool/blob/master/src/test/kotlin/com/animeshz/threadpool/PoolTest.kt#L14 Summary what is going on: 1. While when in creating the pool itself i registered a shutdown hook which prevent the jvm to exit before all tasks have been executed, https://github.com/Animeshz/threadpool/blob/master/src/main/kotlin/com/animeshz/threadpool/Pool.kt#L41 2. And shutdown hook calls join function in the pool which blocks the jvm calling .join() on all the worker threads. And also starts a periodic timer which checks for the worker threads being completed by checking currentlyBusy property on the worker(that i'll explain in point 3) and kills which are not busy. https://github.com/Animeshz/threadpool/blob/master/src/main/kotlin/com/animeshz/threadpool/Pool.kt#L53 3. Worker threads transition their currentlyBusy state by if check when queue(stack) is empty, and "that should only happens if the promise is done executing all the handlers"(but done is not getting executed sometime) , and loops back to stack.dequeue(), and that blocks the thread by an ReentrantLock and since periodic timer in last point i mentioned, interrupts the thread when currentlyBusy property gets false. https://github.com/Animeshz/threadpool/blob/master/src/main/kotlin/com/animeshz/threadpool/Worker.kt#L53 I'm really unable to catch why is that done() block is not executing

Hello, is it possible to have by lazy property which calls suspend function for a value? Eg

val context by lazy { contextProvider() }

where contextProvider() is suspend function

Can I make

xPath

and

contextString

private?

Hey there, I wonder if anyone here can help me. I am doing some work with Kotlin Multiplatform and am running into this kind of exception:

kotlin.native.IncorrectDereferenceException: Trying to access top level value not marked as @ThreadLocal or @SharedImmutable from non-main thread

The context is quite convoluted and I'm not sure if it is relevant or not. I can elaborate further if anyone thinks it might help, but briefly: I've created a Kotlin Multiplatform library (see https://github.com/guardian/multiplatform-ophan) which can send various "events" to an analytics service called "Ophan". I've come up with a way to implement "Native Modules" for React Native applications using shared Kotlin Multiplatform code (see https://github.com/guardian/react-native-with-kotlin) Now I'm trying to put these two ideas together. But unfortunately, although the

multiplatform-ophan

library works as expected when consumed directly from Android or iOS, I run into the above exception on iOS when it is included in a React Native app via this extra layer of indirection. I don't expect anyone to help me debug this issue if it's anything to do with React Native and I appreciate you might think this seems like a very odd combination of things to be doing. But even just some general pointers about the kind of pitfalls you might expect in this area would be greatly appreciated.

Anyone know why I am getting the following error and how to fix it?

So these are the definitions of the 5 kotlin scoping functions

inline fun <T, R> with(receiver: T, block: T.() -> R): R {
    return receiver.block()
}
inline fun <T> T.also(block: (T) -> Unit): T {
    block(this)
    return this
}
inline fun <T> T.apply(block: T.() -> Unit): T {
    block()
    return this
}
inline fun <T, R> T.let(block: (T) -> R): R {
    return block(this)
}
inline fun <T, R> T.run(block: T.() -> R): R {
    return block()
}

What does the

T.() -> R

imply? I know

(T) -> R

is a function that takes a

T

and returns an

R

, but what does

T.()

mean?

I have a code which looks like this

class TeaMaker {
    private lateinit var tea: Tea

    fun prepareTea() {
        tea = Tea()
    }

    fun addSugar() {
        tea.add(Sugar())
    }
}

class Restaurant {
    ...
    //In some method
    val teaMaker = TeaMaker()

    teaMaker.prepareTea()
    teaMaker.addSugar()
}

The problem is when i call addSugar I get the lateinit not initialized exception. I tried setting up debugger but found it is initialised. Am I missing something?

I'm new to kotlin, and created a sample Multiplatform application(common code will be shared between Android and IOS) using https://kotlinlang.org/docs/tutorials/native/mpp-ios-android.html#creating-an-android-project reference. Everything is working fine except

bin

folder is not getting generated in

SharedCode/build

folder

How would a higher-order function in a companion object variable act when being called by multiple threads? Will Kotlin run the function in the caller thread or are objects somehow shared across threads? I need a provided for a thread's namespace and it would be much cleaner to have that provider be a higher-order companion object function but I'm unsure whether it will correctly call the provider from the thread

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Guys... I'm with a problem with ktlint... When I execute, returns me this message:

Process 'command '/usr/lib/jvm/java-11-openjdk-amd64/bin/java'' finished with non-zero exit value 1

Can someone help me please?

Hi wonderful people, I'm wondering what's the difference between those two lines of code:

// First method
val test = Mono.just("hello").run { block() }

// Second method
val test = Mono.just("hello").block()

Both cases

test

has

String?

type

is there a way to create an extension function for an annotated data class?

Hi, I have a basic question. Can you hand me a link that explains the data type hierarchy when declaring a variable? Lets say I have:

val list = mutableListOf<String>()

variable

list

will be a mutable list. but if I have

val list: List<String> = mutableListOf<String>()

variable

list

will be an immutable list. Can someone explain the hierarchy here? Is the defined variable data type always becomes the winning data type?

How to compare Any type arraylist

var getVideoList: ArrayList<Any>

look at this my code https://paste.ofcode.org/PpCQuDjkAvtKpv7U29k7cD

How do I get this to work?

and I've had no response in like a month so I was hoping someone here might know something

Hello - i'm new to the channel, but I wanted to know if anyone has used the new Kotlin Native debugging plugin for 1.3.50-eap-54 (link: https://plugins.jetbrains.com/plugin/12775-native-debug-for-intellij/) - using Idea Ultimate, I have successfully imported and enabled the plugin, updated kotlin to 1.3.50-eap-54, and set the update channel to early access 1.3.x, but even with this, my code does not seem to stop at breakpoints in my native code. Is anyone having similar issues or know how to get around it?

How do I use an extension function that's nested in an object from outside that object? i.e.

object Example {
    fun String.exampleExtension() {
    }
}

fun test(str: String) {
    str.exampleExtension() // Doesn't work. How can I use the extension function?
}

Okay so... I'm developing with Angular CLI now on my web front end, but my backend uses SpringBoot with Kotlin.... seems so incredibly silly to write one part of the app in kotlin and the other part in typescript... is there ever going to be a Kotlin based Angular CLI or is Typescript going to maintain it's monopoly on that platform?

What is the state of native code compilation for Kotlin? My team at work is needing a compiled language without many dependencies and it is Kotlin vs Golang. The ability to compile kotlin to native code is appealing, but someone on my team said they had issues with building a binary for Windows?

is

val nullable = platformTypeVariable ?: null

the correct way to tell Kotlin that a platform type is nullable ?

This message was deleted.

I am trying to get some info about a pretty annoying Java interrop issue (existing issue for example). Does that ring a bell to anyone? It happens with or without the new type inference. https://kotlinlang.slack.com/archives/C0B8ZTWE4/p1565359547058200

So I end up using https://github.com/GoogleChrome/puppeteer a lot for browser automation, but it requires JS. Is there a Kotlin alternative? I’d rather avoid Selenium if I can. Are there any fancy modern libraries for browser automation in Kotlin?

What would be the idiomatic way to do this in Kotlin? I am doing a switch on a String that has well defined values. I'd like to make sure that all these values are handled in the switch statement. I do this in several locations. In other languages, I would have created a function that converts string to some type and then switch on that type. In the "default" section of the switch statement I would have thrown some assertion to make sure all cases are handled.