On Fri, 5 Mar 2021 16:36:03 GMT, Roger Riggs <[email protected]> wrote:
>> This patch optimizes String.format expressions that uses trivial specifiers.
>> In the JDK, the most common variation of String.format is a variation of
>> format("foo: %s", s), which gets a significant speed-up from this.
>>
>> Various other cleanups and minor improvements reduce overhead further and
>> ensure we get a small gain also for more complex format strings.
>
> src/java.base/share/classes/java/util/Formatter.java line 3017:
>
>> 3015: s = ((Character)arg).toString();
>> 3016: } else if (arg instanceof Byte) {
>> 3017: byte i = (Byte) arg;
>
> Can the pattern matching for instanceof be used here to remove explicit
> casts. (Supported in JDK 16)
> s = null;
> if (arg instanceof Character c) {
> s = c.toString();
> } else if (arg instanceof Byte i) {
> if (Character.isValidCodePoint(i))
> s = new String(Character.toChars(i));
> else
> throw new IllegalFormatCodePointException(i);
> } else if (arg instanceof Short i) {
> if (Character.isValidCodePoint(i))
> s = new String(Character.toChars(i));
> else
> throw new IllegalFormatCodePointException(i);
> } ```
> etc..
I did think about it, but it seemed to stray a bit too far from the intent of
this enhancement.
-------------
PR: https://git.openjdk.java.net/jdk/pull/2830
