On Thu, 18 Jul 2024 11:32:47 GMT, Shaojin Wen <[email protected]> wrote:
> class LocalTime {
> public String toString() {
> // ...
> if (nanoValue % 1000_000 == 0) {
> buf.append(Integer.toString((nanoValue / 1000_000) +
> 1000).substring(1));
> } else if (nanoValue % 1000 == 0) {
> buf.append(Integer.toString((nanoValue / 1000) +
> 1000_000).substring(1));
> } else {
> buf.append(Integer.toString((nanoValue) +
> 1000_000_000).substring(1));
> }
> // ...
> }
> }
>
> Currently, LocalTime.toString handles nanos by adding a value and then
> subString(1) to fill it with zeros. Using StringBuilder.repeat is more
> concise and has better performance.
The current logic of adding a value and then substring(1) is not clear, and
this approach is not elegant at all. I think the logic of changing to
repeat('0') is concise and clear.
Using repeat implementation will reduce two object allocations,
Integer.toString & subString(1), and the time consumption will be 1/3 of the
original.
If JLA is not recommended, we can add a stringSize method in LocalTime, similar
to DateTimeFormatterBuilder.
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PR Comment: https://git.openjdk.org/jdk/pull/20232#issuecomment-2236698626
