Re: Different behaviour from Option map in scala compared to Optional map in java

I agree; Some(null) is an abomination, and Option(f(this.get)) would make
more sense.

Actually, in my class Result I wrap all these things (exceptions and nulls)
even for filter and collect, not just map. Meaning, if the predicate called
in filter() throws an exception, that's a legit error, and should be
wrapped as Bad(exception). I think, David Pollak's Box does the same.

Thanks,
-Vlad

On Sun, Apr 17, 2016 at 3:27 AM, Marc Arndt <[email protected]> wrote:

> Hello,
> while programming with java 8 and scala I discovered that both seem to
> have a different behaviour with the method map in the classes Option in
> scala and Optional in java.
> In scala the method map in Option is implemented as followed:
>
>
> *  @inline final def map[B](f: A => B): Option[B] =    if (isEmpty) None
> else Some(f(this.get))*This method requires, that f doesn't return null.
>
> In java the method map in Optional is implemented as followed:
>
>
>
>
>
>
>
> *    public<U> Optional<U> map(Function<? super T, ? extends U> mapper)
> {        Objects.requireNonNull(mapper);        if
> (!isPresent())            return empty();        else {            return
> Optional.ofNullable(mapper.apply(value));        }    }*
> This method does not require, that the given method returns a value not
> null, it is also accepted to return null.
>
> I'm not sure if this behaviour is intended.
>
> Many Greetings
> Marc
>
> --
> You received this message because you are subscribed to the Google Groups
> "scala-language" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> For more options, visit https://groups.google.com/d/optout.
>

-- 
You received this message because you are subscribed to the Google Groups "scala-language" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
For more options, visit https://groups.google.com/d/optout.