delegate method or fields in Kotlin

Question

In Java, IntelliJ and any other IDE will let you automatically create delegate methods to any properties of a class... this helps a lot to speed up the coding process. Is there any way to do something similar in Kotlin?

why?

I had many fields of a class moved to an inner object. Now I need to refactor a giant method adding the extra call to reach these fields... with delegate methods I could solve this in 1 minute in Java... How can I do it in Kotlin?

EXAMPLE

class A(
        var name: String,
        var ref: String,
        var priceCents: Int,
        var maxInstallments: Int = 1,
        ) {

this class became

    class A(
var dto : A_DTO 
            ) {

class A_DTO (
        var name: String,
        var ref: String,
        var priceCents: Int,
        var maxInstallments: Int = 1,
        ) {

So I know everywhere in my code where I had a.name = "" or something = a.name, I will need to change to a.dto.name = "".... something = a.dto.name

In Java, this would be a 2 minute task with no collateral effects. How to do the sams in Kotlin ?

Answer 1

Kotlin has built-in delegation supports. You can use Refractor to extract the interface, then use the by keyword to do the delegation.

interface IA_DTO {
    var name: String
    var ref: String
    var priceCents: Int
    var maxInstallments: Int
}

class A_DTO (
    override var name: String,
    override var ref: String,
    override var priceCents: Int,
    override var maxInstallments: Int = 1,
) : IA_DTO {

}

class A(
    dto : A_DTO
) : IA_DTO by dto
{

}