Enhance Map, List, and Set such that these interfaces extend Function, IntFunction, and Predicate, respectively

[Ralf Spöth]

Thanks for answering that quickly!
Regards
Ralf

> Am 15.09.2022 um 17:34 schrieb Brian Goetz <brian.goetz at oracle.com>:
> 
> 
> 
> On 9/15/2022 11:19 AM, Ralf Spöth wrote:
>> Dear all,
>> 
>> I just stumbled about some frequent uses of collections as filters and mapping functions, and I am wondering whether it's possible to enhance the core collection interfaces Map, List, and Set:
>> 
>> (please forgive lousy syntax hereinafter)
>> 
>> interface Map<K, V> extends Function<K, V> {
>>     default V apply(K k) {return get(k);}
>> }
>> 
>> interface List<T> extends IntFunction<T> {
>>    default T apply(int index) { return get(I);}
>> }
>> 
>> interface Set<T> extends Predicate<T> {
>>    default boolean test(T t) {return contains(t);}
>> }
> 
> These were considered during JSR 335.  They are conceptually sensible, but we decided against it for two reasons:
> 
>  - Adding these methods to highly general interfaces with many implementations extant could introduce conflicts, where someone's `MySet` could have an incompatible "test" method;
> 
>  - The functionality you want is easy accessed via method references: map::get converts to Function (and map::contains to Predicate); list::get conversions to IntFunction; set::contains to Predicate.
> 
>