Performance issue in StringUtils

[jkronegg]

👓 What did you see?

In the Parser.parse() method, 30% to 50% of the elapse time is passed doing String trimming in the StringUtils class, see #351 (comment)

✅ What did you expect to see?

No doubt String trimming is important, but it should not last that long.

📦 Which tool/library version are you using?

OpenJDK21
gherkin 31.0.0 (the main branch)

🔬 How could we reproduce it?

See JMH benchmark code in #351 (comment)

📚 Any additional context?

Identified for #351

[mpkorstanje]

Using a regular expression for trim looks very inefficiënt. It will be applied for every character in line.

It might be faster to find the last consecutive whitespace character from the start and end, and then take a substring.

[jkronegg]

The left trim, right trim and left+right trim operations are used for indentation purposes. Thus, rather than dumbly improving StringUtils, I'm thinking on a specific method which trims and idents at the same time.