[enhanced enums] - end of the road?
Peter Levart
peter.levart at gmail.com
Thu Jun 15 13:07:04 UTC 2017
On 06/15/2017 02:44 PM, Peter Levart wrote:
>>
>> enum Option implements Consumer<String> {
>> D implements Generic<String>("-d", ...) { ... }
>> PROC implements Generic<ProcOption>("-proc", ...) { ... }
>>
>> ...
>>
>> }
>>
>> Which is not too terrible (in fact has been put forward by John as a
>> comment in the JEP [1]).
>>
>
> This is similar, but not the same. In above example, Generic<T> is not
> a subtype of Option. It's just an interface implemented by constant's
> subclasses. So you can not access Option members via an instance of
> Generic<T>... Generic<T> therefore has to declare all the interesting
> methods that can then be implemented by Option. You also have to
> accompany this solution with "sealed" interfaces if you don't want
> other implementations of Generic<T> besides the enum constants...
...in addition, you can not access/modify elements of EnumMap<Option,
...> using keys of type Generic<T> for example - you would have to cast
which is awkward given that your example use case:
public Z get(Generic<Z> option) { ... }
...would probably do just that...
Regards, Peter
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