apache / commons-lang / 1009

95%

Pull #300

travis-ci

Improve StringUtils#replace throughput

Motivation:

`StringUtils#replace` uses `substring` to append a String region into a
StringBuilder. This causes useless copies, as `StringBuilder#append`
can take start and end indexes.

Modification:

Use proper `StringBuilder#append`
[overload](https://docs.oracle.com/javase/8/docs/api/java/lang/StringBui
lder.html#append-java.lang.CharSequence-int-int-).

Result:

Based on benchmark from [JOOQ’s
post](https://blog.jooq.org/2017/10/11/benchmarking-jdk-string-replace-v
s-apache-commons-stringutils-replace):

```
Benchmark Mode Cnt Score Error Units
StringReplaceBenchmark.testFastStringReplaceLongStringOneMatch thrpt 21
7546534,219 ± 145523,962 ops/s
StringReplaceBenchmark.testStringUtilsReplaceLongStringOneMatch thrpt
21 7353512,552 ± 124498,228 ops/s

StringReplaceBenchmark.testFastStringReplaceLongStringSeveralMatches
thrpt 21 5077255,810 ± 62358,937 ops/s
StringReplaceBenchmark.testStringUtilsReplaceLongStringSeveralMatches
thrpt 21 4108357,612 ± 92909,038 ops/s

StringReplaceBenchmark.testFastStringReplaceShortStringOneMatch thrpt
21 15911221,949 ± 541064,693 ops/s
StringReplaceBenchmark.testStringUtilsReplaceShortStringOneMatch thrpt
21 10677897,475 ± 491091,973 ops/s

StringReplaceBenchmark.testFastStringReplaceShortStringSeveralMatches
thrpt 21 9271742,251 ± 220150,121 ops/s
StringReplaceBenchmark.testStringUtilsReplaceShortStringSeveralMatches
thrpt 21 6158829,188 ± 99637,607 ops/s
```

2 of 2 new or added lines in 1 file covered. (100.0%)

14376 of 15101 relevant lines covered (95.2%)

24803.96 hits per line