Kotlin abstract class with generic param and methods which use type param

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I'm trying to create an abstract class with generic parameter which will have subclasses which should call methods without having to specify type parameters. I have this so far:

abstract class AbstractClass<T : Any> @Autowired constructor(protected val delegate: MyService) {
    inline fun <T: Any> myMethod(param: Any): T? {
        return delegate.myMethod(param).`as`(T::class.java)
    }
}

And implementation:

class TesterWork @Autowired constructor(delegate: MyService) : AbstractClass<Tester>(delegate) {
}

Now when calling myMethod I have to specify the type argument:

testerWork.myMethod<Tester>("test")

I was wondering would it be possible to infer the type argument automatically? Can I somehow rework myMethod? Note that I need to have T::class.java inside the method.

kotlin abstract-class type-inference generics
4 Answers

Thanks to Fabian Zeindly I wrote a variant for several extended classes. In this case all of them should be declared in a title of an abstract class.

abstract class AbstractAdapter<V: AbstractAdapter.ViewHolder, I: AbstractAdapter.Item> : RecyclerView.Adapter<V>() {

    var list: List<I> = emptyList()

    override fun getItemCount(): Int = list.size

    open fun setItems(list: List<I>) {
        this.list = list.toMutableList()
    }

    open class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)

    open class Item
}

Then extend the class with new inner classes (ViewHolder, Item).

class NewAdapter(private var listener: View.OnClickListener?) : AbstractAdapter<NewAdapter.ViewHolder, NewAdapter.Item>() {

    private var originalItems: List<Item> = emptyList()

    override fun setItems(list: List<Item>) {
        super.setItems(list)
        this.originalItems = list.toMutableList()
        this.list = list.toMutableList()
    }

    override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): ViewHolder {
        val view = LayoutInflater.from(viewGroup.context)
            .inflate(R.layout.layout, viewGroup, false)

        return ViewHolder(view)
    }

    override fun onBindViewHolder(viewHolder: ViewHolder, i: Int) {
        val item = list[i]
        viewHolder.textView.text = item.text
        viewHolder.textView.tag = item.id
    }

    class ViewHolder(itemView: View) : AbstractAdapter.ViewHolder(itemView) {
        val textView: TextView = itemView.name
    }

    class Item(val id: Int, val text: String) : AbstractAdapter.Item()
}
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