Also with Spring Framework 5.0, you won’t have to specify

required

attribute, it will be automatically deduced from Kotlin nullable information.

if you care about being able to use the upcoming Spring functional Web Framework with Kotlin, please vote for https://youtrack.jetbrains.com/issue/KT-14984.

See https://spring.io/blog/2016/09/22/new-in-spring-5-functional-web-framework for more details about the functional web Framework

I will shortly release a sample Kotlin app using it

That basicaly Spring app using lambdas instead of annotations

No classpath scanning, low memory consumption, etc.

The pain point with Kotlin is that we have to specify explicitly

HandlerFunction { …}

instead of just

{ … }

That’s really hard to fix and will not be fixed in 1.1. Your best bet here is to create a specific Kotlin overload with one Runnable and one Function.

@orangy Ok I will try to provide a Kotlin specific workaround. I am not sure to understand your proposal about creating "a specific Kotlin overload with one Runnable and one Function”. Could you please detail a little bit?

Kotlin creates a synthetic overload replacing SAM types with functional types with matching signature. It creates only one for all SAMs, not every permutation.

Ok

So you need to have

fun foo(Runnable, KFunction1)

or similar

So maybe the issue I was about to work will solve this

I am going to add shortcut functions

That will remove the

RequestPredicate

And let only the

HandlerFunction

That would be a nice tradeoff without Kotlin specific hack

I am going to try

Thanks for your feedback

Ok with shortut methods that works without having to specified the type of the lambda 🙂

So this issue is less critical now

This will quickly become a real production ready project, it’s not just a demo

When the functional bean registration API will be available and used, this Spring project will not use Reflection at all.

It already use lambda based routes instead of annotation

Good fit with Kotlin I think

Hey Sébastien, is this snippet correct for Spring?

@RestController
class CustomerController(val repository: CustomerRepository) {

    @GetMapping("/customers")
    fun findAll() = repository.findAll()

    @GetMapping("/{lastName}")
    fun findByLastName(@PathVariable lastName: String) = repository.findByLastName(lastName)
}

if I leave this in my project then simple resolving

/

->

/index.html

stops working and it's hitting this controller for some reason

wait.. I am mapping the lastName to the slash right?