Sponsor for 6666666: A better implementation of Character.isSupplementaryCodePoint

[Martin Buchholz]

On Tue, Mar 16, 2010 at 13:27, Ulf Zibis <Ulf.Zibis at gmx.de> wrote:
> Am 13.03.2010 00:29, schrieb Martin Buchholz:
>
> Won't you like to add:
>     * <p><b>Note:</b> In combination with {@link #isBMPCodePoint(int)} this
>     * method should be in 2nd place to permit additional HotSpot compiler
>     * optimization. Example:
>     * <blockquote><pre>
>     *     if (Character.isBMPCodePoint(codePoint))
>     *         ...;
>     *     else if (Character.isSupplementaryCodePoint(codePoint))
>     *         ...;
>     *     else
>     *         ...;
>     * </pre></blockquote>
>     *

No.

This kind of implementation-specific comment is not
traditionally put in public javadoc (it's considered OK
in private comments).  Also, we should not inflict our
dangerous micro-optimization disease on others.

>> 6934265: Add public method Character.isBMPCodePoint
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk7/public-isBMPCodePoint
>>
>
> Additionally please move static final int SIZE = 16 to one of the first
> lines of the code.
> See: https://bugs.openjdk.java.net/attachment.cgi?id=178&action=diff

No.

Although I agree with you that SIZE would be better near the top of the
class, I am not going to move it, at least not now.
For consistency, the SIZE fields in related classes like Short
should be moved as well.

>> 6934270: Remove javac warnings from Character.java
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Character-warnings
>> 6934271: Better handling of longer utf-8 sequences
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk7/utf8-twiddling
>> 6666666: Optimize bit-twiddling in Bits.java
>> http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Bits.java
>>
>
> Hm, I can't see any difference that would merit to see it as
> micro-optimization. Am I blind?

Bytecode is smaller.

>> Now I need to go off to my micro-optimizers-anonymous meeting.
>>
>
> Oh, you are coming to Cologne, Germany. Nice to meet you personally.

Das letzte Mal war ich in Köln zu Bewerbungsinterview.
Leider nur Stellungen in der Versicherungsindustrie zu der Zeit.

Martin