On Tue, 17 Oct 2023 12:16:54 GMT, ExE Boss <d...@openjdk.org> wrote:
>> This PR proposes to add a number of "capturing factories" in classes in the
>> `java.util.function` package.
>>
>> The PR additionally (an optionally) proposes to add a new function
>> `UnaryOperator::andThenUnary` to allow composition while retaining the
>> `UnaryOperator` type.
>>
>> With the new changes, it is possible to write code like this (example from
>> `java.util.function.Function`):
>>
>>
>> // Resolve ambiguity
>> var function = Function.of(String::isEmpty); // Function<String, Boolean>
>> var predicate = Predicate.of(String::isEmpty); // Predicate<String>
>>
>> // Fluent composition
>> var chained = Function.of(String::length) // Function<String, Integer>
>> .andThen(Integer::byteValue); // Function<String,
>> Byte>
>>
>>
>> Please see the original bug report for a comprehensive description of these
>> proposed changes.
>>
>> Note: It is not the objective to promote `var` declaration or to prevent
>> previous ways of capturing lambdas and method references. The comments in
>> the code above is for explaining the binding and once that becomes obvious,
>> such comments are likely to not appear in real code. Users that prefers
>> having a normal type declaration can still do that.
>>
>> Note: Functional interfaces of primitives have not been considered (in this
>> round). Otherwise, functional interfaces that might be ambiguous or that
>> supports composition have been included. Hence, `Supplier` did not get a
>> factory method.
>
> src/java.base/share/classes/java/util/function/BiConsumer.java line 104:
>
>> 102: * @param <U> the type of the second argument to the operation
>> 103: */
>> 104: static <T, U> BiConsumer<T, U> of(BiConsumer<T, U> uncaptured) {
>
> Suggestion:
>
> static <T, U> BiConsumer<T, U> of(BiConsumer<? super T, ? super U>
> uncaptured) {
@ExE-Boss This and all other "enhancements" hardly compile ;-)
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PR Review Comment: https://git.openjdk.org/jdk/pull/16213#discussion_r1362076569
