从Java迁移到kotlin-SAM包装程序的挑战吗？

Question

I have a Java SAM interface and an implementation I want to translate in kotlin:

public interface CallbackWrapper {
    <T> Consumer<T> wrap(Consumer<T> consumer);
}

public class MainThreadWrapper implements CallbackWrapper {

    @Override
    public  <T> Consumer<T> wrap(Consumer<T> consumer) {
        return i -> {
            Handler handler = new Handler(Looper.getMainLooper());
            handler.post(() -> consumer.accept(i));
        };
    }
}

Of course our project can deal with the java code but my neurons cannot. ;)

Any help wiil be appreciated.

Patrice

Answer 1

The equivalent Kotlin class would look like this:

class MainThreadWrapper : CallbackWrapper {
    override fun <T> wrap(consumer: Consumer<T>): Consumer<T> =
        Consumer { t ->
            val handler = Handler(Looper.mainLooper)
            handler.post { consumer.accept(t) }
        }
}

Note that the code uses SAM conversions two times, and they are only available for interfaces declared in Java. The Kotlin alternatives are function types or object expressions for anonymous interface implementations.