Matcher performance improvements

[Xueming Shen]

The RFE#5066679 has been on my "next week's todo list" for a while:-) it 
looks like
the Appendable might be a better choice here? I guess we should gain the 
same performance
when you pass in a StringBuilder. Opinion?

Sherman

Martin Buchholz wrote:
> Hi regex/String team,
>
> We would like to contribute a performance improvement for Matcher.
>
> Please file a bug.
>
> category: java_util_regex
> Synopsis: Faster Matcher by replacing StringBuffer with StringBuilder
>
> Description:
> The old Matcher API and implementation depend on the old StringBuffer class.
> The use of StringBuilder gives measurable performance improvement in
> real world applications.
> http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Matcher-perf/
> Written by Jeremy Manson.
>
> Here's a microbenchmark, where it gives 25% win:
>
> public class StringReplace {
>   static String jabber = "Twas brillig, and the slithy toves " +
>       "Did gyre and gimble in the wabe; " +
>       "All mimsy were the borogoves, " +
>       "And the mome raths outgrabe. " +
>       " " +
>       "Beware the Jabberwock, my son! " +
>       "The jaws that bite, the claws that catch! " +
>       "Beware the Jubjub bird, and shun " +
>       "The frumious Bandersnatch!" +
>       " " +
>       "He took his vorpal sword in hand: " +
>       "Long time the manxome foe he sought— " +
>       "So rested he by the Tumtum tree, " +
>       "And stood awhile in thought. " +
>       " " +
>       "And as in uffish thought he stood, " +
>       "The Jabberwock, with eyes of flame, " +
>       "Came whiffling through the tulgey wood, " +
>       "And burbled as it came! " +
>       " " +
>       "One, two! One, two! and through and through " +
>       "The vorpal blade went snicker-snack! " +
>       "He left it dead, and with its head " +
>       "He went galumphing back. " +
>       " " +
>       "And hast thou slain the Jabberwock? " +
>       "Come to my arms, my beamish boy! " +
>       "O frabjous day! Callooh! Callay!" +" " +
>       "He chortled in his joy. " +
>       " " +
>       "'Twas brillig, and the slithy toves " +
>       "Did gyre and gimble in the wabe; " +
>       "All mimsy were the borogoves, " +
>       "And the mome raths outgrabe?";
>
>   public static void replace() {
>     long start = System.currentTimeMillis();
>     for (int i = 0; i < 100000; i++) {
>       jabber.replaceAll("the", "ze");
>     }
>     long stop = System.currentTimeMillis();
>     System.out.println(stop);
>     System.out.println(start);
>
>     System.out.println(stop - start);
>   }
>
>   public static void main(String[] args) {
>     for (int i = 0; i < 5; i++) {
>       replace();
>     }
>   }
> }
>