Hey is there anything like partial classes in Kotlin Lets sa kotlinlang #getting-started

Hey, is there anything like partial classes in Kotlin? Lets say that I have a Post model with (id, title, content, createdAt, updatedAt) and I want to have only the primary fields (title, content) for the DTO Which way would be the most efficient to handle that in Spring Boot with Kotin

Richard Gomez

05/06/2022, 8:39 PM

No, unfortunately not. I recall seeing a third-party dependencies (perhaps a compiler plugin) that accomplished that, but idk how reliable that would be.

The most pragmatic solution is just to make separate DTOs per use case. So

CreatePostDto

CreatePostRequest

(pick your poison) only has title and content, and

ReadPostDto

has all attributes, etc.

Okan Yıldırım

05/06/2022, 8:41 PM

So I would have to create both the

Entity

and the

Dto

seperately

A little bit repeating but probably won't harm anything 😄

Richard Gomez

05/06/2022, 8:45 PM

A little bit repeating but probably won't harm anything

While it may seem a bit awkward, I'd argue that it's a good approach. That way your DTO models aren't tied to your entity models.

Of course if this is just a tiny CRUD app or whatever that probably doesn't matter. But it can be useful in large apps.

phldavies

05/06/2022, 8:46 PM

Also you may wish to have extension methods to convert between them, e.g.

fun Post.toDTO() = PostDTO(title, content)

Okan Yıldırım

05/06/2022, 8:49 PM

Great, thanks guys

I just want to ask a last question

Can I use

modelmapper:modelmapper

on Kotlin?

So that I can convert my DTO to Entity

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