Does the Java regular expression library optimize for any characters. *?

Question

I have a wrapper class for matching regular expressions. Obviously, you are compiling a regex in Patternlike this.

Pattern pattern = Pattern.compile(regex);

But suppose I used .*to indicate any number of characters. So this is basically a template.

Pattern pattern = Pattern.compile(".*");

Does the template optimize to always return true and not calculate anything? Or do I need my shell to implement this optimization? I do this because I can easily handle hundreds of thousands of regular expression operations in the process. If the regex parameter is zero, I will combine it with.*

Answer 1

, :

.*+

Java .

Java , .*:

Java regex engine .*abc.*. , abc , . String.indexOf("abc") , . , , . , .{100}abc.*, . ? abc ( ).

Java :

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• - . , \d{100} , 100 , .
• , . , ,
• , Pattern.compile() Pattern.matches().
• , Matcher , reset().
• . (X|Y|Z) , . , , , . , ; , (abcd|abef) ab(cd|ef).
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• , , . , , .
• # 5050507 ( regex Pattern StackOverflowError), , . .

• (, (?:(?!something).)*) ( downvoted , ).

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