skittles monad - factory method approach

package skittles.monad.factorymethod;

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);
    }

    // abstract Monad can use this factory method to create new monads, but let
    // sub-classes decide how exactly and which impl of Monad to create
    public abstract Monad<T, E> create(T value);
}











package skittles.monad.factorymethod;

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

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