`val handler: Handler = { req, res -> res.body(...

# getting-started

[kingsley]

val handler: Handler = { req, res -> res.body("Hello") }

Is it bad practice? To declare lambdas? No, it's perfectly fine.

[tipsy]

kingsley: that works with the java version, but if i convert the interface to kotlin:

@FunctionalInterface
@Throws(Exception::class)
fun handle(request: Request, response: Response)

i need to add a constructor in order to do that

[tipsy]

i'm not sure how smart the conversion tool is

[kingsley]

Yes. Kotlin interfaces are not SAM capable. You'd need use a functional type with typealias instead to achieve the same

typealias Handler = (Request, Response) -> Unit

[tipsy]

thanks, that helps

[kingsley]

You're welcome

[tipsy]

maybe the best approach here would be to keep the functional interfaces as java, since i intend to use this with both java and kotlin? or is there a better approach?

[kingsley]

Yes. You can do that. Using Kotlin's functional type results in FunctionN interfaces in Java which might not be as pretty as a specialized interface like your Handler

[kingsley]

Well. Except you intend for a 100% KT src, in which case, you'll eventually end up converting everything anway