Enum enhancement

[Tagir Valeev]

As for (2) probably Optional<E> findValue(String name) would be better, as
you may decide what to do if it's absent using all the optional API.

With best regards,
Tagir Valeev.

пт, 7 дек. 2018 г., 21:28 Brian Goetz brian.goetz at oracle.com:

> (1) is already tracked as
>
>      https://bugs.openjdk.java.net/browse/JDK-8073381
>
> It is not as "easy" as you think in that these enum methods are
> generated by the compiler, not as ordinary library code, but it's not
> prohibited.
>
> (2) is not unreasonable.  As there's no language component to it, you
> could take this directly to corelibs-dev for further evaluation.
>
> On 12/7/2018 9:13 AM, Giguere, Thierry wrote:
> > Hello,
> >
> > Related to the follow link and JEP 301<https://openjdk.java.net/jeps/301>
> :
> >
> >
> http://mail.openjdk.java.net/pipermail/amber-spec-experts/2018-December/000876.html
> >
> > What is also missing and long-time due for enum right now and could be
> added quickly is more methods:
> >
> > 1) We need to be able to iterate efficiently on enum. Currently calling
> method T[] values() duplicate the internal array. Moreover you need to go
> through method Arrays.stream() to convert the newly created array to
> stream. Adding a stream() method and a forEach() method would help fix this
> problem. Optionally a iterator() method could be provided
> >
> >        Arrays.stream(MyEnum.values()).forEach();
> >
> > could be replaced by something like :
> >
> >        MyEnum.forEach();
> >
> > And
> >
> >        Arrays.stream(MyEnum.values()).map(...
> >
> > could be written :
> >
> >        MyEnum.stream().map(...
> >
> > 2) T valueOfOrDefault : pretty much like getOrDefault of the map
> interface. This method don't throw exception and fallback on default value.
> That would ease use of enum in stream / lambda programming
> >
> >              @Nonnull
> >              MyEnum myEnum = MyEnum.DEFAULT_VALUE;
> >
> >              try {
> >                    myEnum = MyEnum.valueOf(...);
> >              } catch (NullPointerException | IllegalArgumentException e)
> {
> >                    // Just keep going with on the default value
> >              }
> >
> > Since exception are thrown it doesn't fit very well in stream / lambda
> usage. Something like this :
> >
> > MyData.stream().map(MyEnum::valueOf).forEach()
> >
> > Must be converted to :
> >
> >                  MyData.stream().map(d -> {
> >                                 try {
> >                                                  return
> MyEnum.valueOf(...);
> >                                 } catch (Exception e) {
> >                                                  return
> MyEnum.DEFAULT_VALUE;
> >                                                }
> >                  }).forEach();
> >
> > It would be great to write at least something like :
> >
> >                  MyData.stream().map(d -> MyEnum.valueOfOrDefault(d,
> MyEnum.DEFAULT_VALUE)).forEach();
> >
> > My feeling is these enhancement could be easily and quickly added
> >
> > Thierry Giguère
> >
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