skittles monad - class knows about sub-classes

package skittles.monad.knowsimpl;

import javax.lang.model.type.NullType;
import java.util.function.Function;

public abstract class Monad<T, E> {
    private final T value;

    public Monad(T value) {
        this.value = value;
    }

    public T extract() {
        return this.value;
    }

    public Monad<NullType, E> bind(Function<T, Monad<NullType, E>> f) {
        return f.apply(value);
    }

    public Monad<NullType, E> sequencer(Monad<NullType, E> b) {
        return bind(__ -> b);
    }

    public static <T, E> Monad<T, E> create(T value) {
        return new Kek<>(value);
    }
}






package skittles.monad.knowsimpl;

public class Kek<T, E> extends Monad<T, E> {
    public Kek(T value) {
        super(value);
    }
}