``` class Bar lt T gt protected constructor type Class lt T gt companion object inline operator fun lt reified T gt invoke Bar lt T gt return Bar T class java val bar = Bar lt String gt ```

class Bar<T> protected constructor(type: Class<T>) {
    companion object {
        inline operator fun <reified T> invoke(): Bar<T> {
            return Bar(T::class.java)
        }
    }
}

val bar = Bar<String>()

diesieben07

03/09/2018, 3:33 PM

Not sure I follow how I would use this.

christopher

03/09/2018, 3:34 PM

Not sure where the disconnect is. This lets you use

Bar<Type>()

instead of

Bar(Type::class.java)

. Not what you wanted?

diesieben07

03/09/2018, 3:35 PM

Yes, that is what I wanted. However I want this to be a companion object.

christopher

03/09/2018, 3:35 PM

it is?

the

val bar

at the end is just a demonstration.

diesieben07

03/09/2018, 3:35 PM

In your case

Bar

has the class parameter. The companion object should have it.

christopher

03/09/2018, 3:35 PM

It does…

Oh, you don’t want the type parameter on the class?

diesieben07

03/09/2018, 3:36 PM

Yes.

christopher

03/09/2018, 3:36 PM

well, it doesn’t have to be there. but then your parent class won’t know what type of class it’s getting, just that it’s a class

diesieben07

03/09/2018, 3:36 PM

data class Person

should have a companion object of type

Model<Person>

, and

Model

needs the

Person

class.

Model

then has methods like

findAll

, which would return all

Person

instances.

christopher

03/09/2018, 3:38 PM

Type it out as you want it to look, if reified were possible where you want it.

diesieben07

03/09/2018, 3:39 PM

class Model<reified T>

I know I can emulate that using factory method. However then I can no longer use it as companion object...

christopher

03/09/2018, 3:42 PM

oh I see

diesieben07

03/09/2018, 3:43 PM

I think delegation using

by

is the best I can do...

christopher

03/09/2018, 3:43 PM

yup, I think so

I’ve been working on an annotation processor to auto generate interfaces for that purpose actually 😆

diesieben07

03/09/2018, 3:45 PM

I am trying to move away from annotation processing 🙂 Otherwise I'd being using querydsl or something. But I am trying to be "kotlin idiomatic" in a way 🙂

christopher

03/09/2018, 3:47 PM

👍

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