On Fri, 19 Apr 2024 12:59:24 GMT, Evemose <d...@openjdk.org> wrote:
>> **Subject**
>> Addition of Predicate-based `indexOf` and `lastIndexOf` methods to
>> `java.util.List`
>>
>> **Motivation**
>> The motivation behind this proposal is to enhance the functionality of the
>> `List` interface by providing a more flexible way to find the index of an
>> element. Currently, the `indexOf` and `lastIndexOf` methods only accept an
>> object as a parameter. This limits the flexibility of these methods as they
>> can only find the index of exact object matches.
>>
>> The proposed methods would accept a `Predicate` as a parameter, allowing
>> users to define a condition that the desired element must meet. This would
>> provide a more flexible and powerful way to find the index of an element in
>> a list.
>>
>> Here is a brief overview of the changes made in this pull request:
>>
>> 1. Added the `indexOf(Predicate<? super E> filter)` method to the `List`
>> interface.
>> 2. Added the `lastIndexOf(Predicate<? super E> filter)` method to the `List`
>> interface.
>> 3. Implemented these methods in all non-abstract classes that implement the
>> `List` interface.
>>
>> The changes have been thoroughly tested to ensure they work as expected and
>> do not introduce any regressions. The test cases cover a variety of
>> scenarios to ensure the robustness of the implementation.
>>
>> For example, consider the following test case:
>>
>> List<String> list = new ArrayList<>();
>> list.add("Object one");
>> list.add("NotObject two");
>> list.add("NotObject three");
>>
>> int index1 = list.indexOf(s -> s.contains("ct t"));
>> System.out.println(index1); // Expected output: 1
>> int index2 = list.lastIndexOf(s -> s.startsWith("NotObject"));
>> System.out.println(index2); // Expected output: 2
>>
>>
>> Currently, to achieve the same result, we would have to use a more verbose
>> approach:
>>
>> int index1 = IntStream.range(0, list.size())
>> .filter(i -> list.get(i).contains("ct t"))
>> .findFirst()
>> .orElse(-1);
>> System.out.println(index1); // Output: 1
>> int index2 = IntStream.range(0, list.size())
>> .filter(i -> list.get(i).startsWith("NotObject"))
>> .reduce((first, second) -> second)
>> .orElse(-1);
>> System.out.println(index2); // Output: 2
>>
>>
>> I believe these additions would greatly enhance the functionality and
>> flexibility of the `List` interface, making it more powerful and
>> user-friendly. I look forward to your feedback and am open to making any
>> necessary changes bas...
>
> Evemose has updated the pull request incrementally with one additional commit
> since the last revision:
>
> Update Vector.java
Please revert the formatting as soon as possible; its noise as far as reviewers
are concerned.
You want reviewers to focus on the suitability of the API and clarity of the
specification first, then later on the implementation. Thanks
-------------
PR Comment: https://git.openjdk.org/jdk/pull/18639#issuecomment-2066673266
