kotlinlang #getting-started

Hi all. Trying to play with Kotlin and JPA. Got error while query entity InstantiationException: No default constructor for entity. I solve it for Jackson by adding dependency... but how to solve it with JPA?

panov.andy

02/18/2017, 11:02 PM

Please 🙂

coletz

02/18/2017, 11:07 PM

Not sure if I'm right, but it seems like you must add the default constructor, aka an empty one class YourClass(){}

panov.andy

02/18/2017, 11:10 PM

I found example... not understand why it's not working for me https://github.com/sdeleuze/spring-boot-kotlin-demo/blob/master/src/main/kotlin/hello/CustomerController.kt

panov.andy

02/18/2017, 11:18 PM

Seems we have plugin which create no-args constructor for us https://blog.jetbrains.com/kotlin/2016/12/kotlin-1-0-6-is-here/

panov.andy

02/18/2017, 11:35 PM

😞 doesn't work

panov.andy

02/18/2017, 11:42 PM

ah... doesn't work from IDEA but work if I run mvn spring-boot:run

evkaky

02/19/2017, 2:07 PM

Hi all. Are there any simple built-in possibility to iterate over a List<T> in the reverse order? I know about syntax like this for the ranges:

for (i in 4 downTo 1)

but I want to iterate over List<T> like this one:

val names = listOf("bob", "ben", “nick”)

for (i in names downTo) {

// i == "nick" on the first iteration

It seems I can't do it with range-loop, only with old "while" loop. Am I right?

bob

02/19/2017, 2:10 PM

you can always do a

names.reversed()

to reverse the list and iterate over it.

voddan

02/19/2017, 2:13 PM

use

names.asReversed()

to avoid copying

➕ 1

miha-x64

02/19/2017, 2:14 PM

Copy code

fun <T> List<T>.forEachReversed(consumer: (T)->Unit) {
    // hope `this is RandomAccess`
    for (i in size - 1 downTo 0) {
        consumer(get(i))
    }
}

evkaky

02/19/2017, 2:24 PM

wow, thanks a lot

Tristan Caron

02/19/2017, 3:44 PM

Hello, I'm facing this error. I would like to have an object which implements an interface.

Tristan Caron

02/19/2017, 3:44 PM

@User uploaded a file:

Capture d’écran 2017-02-19 à 16.44.19.png▾

user

02/19/2017, 3:47 PM

@miha-x64 commented on @Tristan Caron’s file

https://kotlinlang.slack.com/files/U1DKTH3NW/F47DX3JDR/capture_d___e__cran_2017-02-19_a___16.44.19.png▾

: Looks quite impossible to implement an interface (even it is not guaranteed that it is an interface) which is specified by a not reified type.

nekoinemo

02/20/2017, 8:21 AM

Hello. I've encountered a little problem with updating to rc-91: i use gradle kotlin script and after update all of the dsl in my build.gradle.kts got marked as "compiled by a pre-release version of Kotlin and can't be loaded". I can't seem to find a way to update org.gradle.script.lang.kotlin in my project. Can somebody point me in the right direction, please?

orangy

02/20/2017, 8:50 AM

@nekoinemo current GSK is indeed built with pre-release version of Kotlin, so you need to ask in #gradle when they are going to release an update for RC

izorin

02/20/2017, 11:37 AM

what is the best way to supply define default value in case of

NoSuchElementException

izorin

02/20/2017, 11:37 AM

@User uploaded a file: Untitled

-.kt

bernhard

02/20/2017, 11:38 AM

Copy code

val result = it.lastOrNull { somePredicate } ?: yourDefaultValue

👍 1

izorin

02/20/2017, 11:39 AM

thanks, it was pretty obvious =(

bernhard

02/20/2017, 11:39 AM

you are welcome 😉

janvladimirmostert

02/20/2017, 11:47 AM

@izorin It's only obvious if you've known about lastOrNull and have been using it on a regular basis. Good question IMO

voddan

02/20/2017, 12:44 PM

^^btw, this is not a hack, but the intended use. Should be in the docs IMO

bts.rybicki

02/20/2017, 1:33 PM

@User uploaded a file: Untitled

-.txt

bts.rybicki

02/20/2017, 1:33 PM

hello, does anyone know why my event hasn't been sent?

bts.rybicki

02/20/2017, 1:33 PM

I wanted to send event every time I change collection value

bts.rybicki

02/20/2017, 1:34 PM

is my syntax wrong?

nekoinemo

02/20/2017, 1:34 PM

You mean send the event when you reassign the map?