RFR: 8343110: Add getChars(int, int, char[], int) to CharSequence and CharBuffer [v6]

[Alan Bateman]

On Thu, 17 Apr 2025 21:29:21 GMT, Markus KARG <duke at openjdk.org> wrote:

>> This Pull Request proposes an implementation for [JDK-8343110](https://bugs.openjdk.org/browse/JDK-8343110): Adding the new method `public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)` to the `CharSequence` interface, providing a **bulk-read** facility including a default implementation iterating over `charAt(int)`.
>> 
>> In addition, this Pull Request proposes to replace the implementation of `Reader.of(CharSequence).read(char[] cbuf, int off, int len)` to invoke `CharSequence.getChars(next, next + n, cbuf, off)` instead of utilizing pattern matching for switch. Also, this PR proposes to implement `CharBuffer.getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)` as an alias for `CharBuffer.get(srcBegin, dst, dstBegin, srcEnd - srcBegin)`.
>> 
>> To ensure quality...
>> * ...the method signature and JavaDocs are adapted from `AbstractStringBuilder.getChars(...)`.
>> * ...this PR relies upon the existing tests for `Reader.of(CharSequence)`, as these provide sufficient coverage of all changes introduced by this PR.
>
> Markus KARG has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Applied changes requested by Chen and Jaikiran: Unit tests for default implementation of CharSequence.getChars() and for CharBuffer.getChars()

test/jdk/java/nio/CharBuffer/GetChars.java line 34:

> 32:  * @run testng GetChars
> 33:  */
> 34: public class GetChars {

The tests for buffers, including CharBuffer, are in test/jdk/java/nio/Buffer. Look at the existing Chars.java tests idea, and specifically the DataProvider "createCharBuffers" as it will show the different kinds of CharBuffers that can be tested.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21730#discussion_r2050100315