RFR: JDK-8302323 Add repeat methods to StringBuilder/StringBuffer [v3]

[Tagir F. Valeev]

On Mon, 27 Feb 2023 13:30:47 GMT, Jim Laskey <jlaskey at openjdk.org> wrote:

>> Add the ability to repeatedly append char and CharSequence data to StringBuilder/StringBuffer.
>
> Jim Laskey has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Optimize for empty CharSequence

src/java.base/share/classes/java/lang/AbstractStringBuilder.java line 1879:

> 1877:      * @since 21
> 1878:      * @throws IllegalArgumentException  if {@code count} is less than zero
> 1879:      * @throws IndexOutOfBoundsException  if the result overflows the buffer

Can `IndexOutOfBoundsException` be really thrown? We don't have any index here. From the implementation I see that only `OutOfMemoryError` and `IllegalArgumentException` can be thrown.

Also, I see a small descrepancy between messages in this method and `String.repeat`. The latter has:


     * @throws  IllegalArgumentException if the {@code count} is
     *          negative.
     *
     * @since 11
     */
    public String repeat(int count) {
        if (count < 0) {
            throw new IllegalArgumentException("count is negative: " + count);
        }


Probably it's better to reuse the same wording ("is negative" instead of "is less than zero") for consistency?

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PR: https://git.openjdk.org/jdk/pull/12728