CODEWITHSUNDEEP
springspring-bootgenericskotlin
julien dumortier
julien dumortier

Reputation: 1303

Type not recognized with generics method in Kotlin

I have this interface with this generic method:

interface IInterface {
    fun <T> test(body: T)
}

I want to implement this interface like this:

class MyClass: IInterface {
    override fun <JsonObject> test(body: JsonObject) {
        if (body is com.google.gson.JsonObject) {

        }
    }
}

My problem here is type JsonObject not recognized like "com.google.gson.JsonObject". So i can write this code without error in my compilator (intelliJ).

override fun <NotExistingClass__> test(body: NotExistingClass__) {

So, how to define the type of T for JsonObject from Gson ? this code does not work:

override fun <com.google.gson.JsonObject> test(body: com.google.gson.JsonObject)

Thank's

Upvotes: 1

Views: 219

Answers (1)

Adam Arold
Adam Arold

Reputation: 30528

This interface:

interface IInterface {
    fun <T> test(body: T)
}

is not generic, but it has a generic method. If you want to make it generic do this:

interface IInterface<T> {
    fun test(body: T)
}

then your implementation will look like this:

class MyClass: IInterface<JsonObject> {
    override fun test(body: JsonObject) {
        if (body is com.google.gson.JsonObject) {

        }
    }
}

If you still want a generic method for some reason you'll have to pass the generic type parameter at each call site:

someInstance.test<JsonObject>(obj)

Upvotes: 2

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