Refactor regex Pattern into Java flavor pattern

Question

I have a regex pattern created on regex101.com: https://regex101.com/r/cMvHlm/7/codegen?language=java

however, that regex does not seem to work in my Java program (I use spring toolsuite as IDE):

@Test
    public void testRegex() {
        //Pattern referenceCodePattern = Pattern.compile("((\\h|\\:)+)(([\u00DFA-Za-z0-9-_#\\\\\\/])+)(([[:punct:]])?)");
        Pattern pattern = Pattern.compile(""
                + "(?:\\s+|chiffre|job-id|job-nr[.]|job-nr|\\bjob id\\b|job nr[.]|jobnummer|jobnr[.]|jobid|jobcode|job nr.|ziffer|kennziffer|kennz.|referenz code|referenz-code|"
                + "referenzcode|ref[.] nr[.]|ref[.] id|ref id|ref[.]id|ref[.]-nr[.]|ref[.]- nr[.]|"
                + "referenz nummer|referenznummer|referenz nr[.]|stellenreferenz| referenz-nr[.]|referenznr[.]|referenz|referenznummer der stelle|id#|id #|stellenausschreibungen|" 
                + "stellenausschreibungs\\s?nr[.]|stellenausschreibungs-nr[.]|stellenausschreibungsnr[.]|stellenangebots id|stellenangebots-id|stellenangebotsid|stellen id|stellen-id|stellenid|stellenreferenz|"
                + "stellen-referenz|ref[.]st[.]nr[.]|stellennumer|\\bst[.]-nr[.]\\b|\\bst[.] nr[.]\\b|kenn-nr[.]|positionsnummer|kennwort|stellenkey|stellencode|job-referenzcode|stellenausschreibung|"
                + "bewerbungskennziffer|projekt id|projekt-id|reference number|reference no[.]|reference code|job code|job id|job vacancy no[.]|job-ad-number|auto req id|job ref|\\bstellenausschreibung nr[.]\\b)"
                + ":?(?:\\w*)(?:\\s*)([A-Z]*\\s*)([!\"#$%&'()*+,\\-.\\/:;<=>?@[\\]^_`{|}~]*\\w*[!\"#$%&'()*+,\\-.\\/:;<=>?@[\\]^_`{|}~]*\\w*[!\"#$%&'()*+,\\-.\\/:;<=>?@[\\]^_`{|}~]*\\w*[!\"#$%&'()*+,\\-.\\/:;<=>?@[\\]^_`{|}~]*)?");

        String line = "Referenznummer: INDUSTRY Kontakt: ZAsdfsdfS Herr Andrafgdh Neue Str. 7 21244 Buchholz +42341 22322 mdjob.bu44lz@zaqusssis.de Stellenanzeige teilen: Jetzt online bewerben! oder bewerben Sie sich mit\n" +
            "Geben Sie bei Ihrer Bewerbung die Stellenreferenz und die Stellenbezeichnung an! \n" +
            "Stellenreferenz:   21533448-JOtest\n\n" +
            "Stellenausschreibung Nr. PD-666/19";


          // Create a Pattern object
          //Pattern r = Pattern.compile(pattern);
          Matcher m = pattern.matcher(line);
          if (m.find( )) {
             System.out.println("Found value: " + m.group(0) );
             System.out.println("Found value: " + m.group(1) );
             System.out.println("Found value: " + m.group(2) );
          }else {
             System.out.println("NO MATCH");
          }                 
    }

I get the following error:

    java.util.regex.PatternSyntaxException: Unclosed character class near index 1337

    at java.util.regex.Pattern.error(Pattern.java:1957)
    at java.util.regex.Pattern.clazz(Pattern.java:2550)
    at java.util.regex.Pattern.clazz(Pattern.java:2506)
    at java.util.regex.Pattern.clazz(Pattern.java:2506)
    at java.util.regex.Pattern.clazz(Pattern.java:2506)
    at java.util.regex.Pattern.sequence(Pattern.java:2065)
    at java.util.regex.Pattern.expr(Pattern.java:1998)
    at java.util.regex.Pattern.group0(Pattern.java:2907)
    at java.util.regex.Pattern.sequence(Pattern.java:2053)
    at java.util.regex.Pattern.expr(Pattern.java:1998)
    at java.util.regex.Pattern.compile(Pattern.java:1698)
    at java.util.regex.Pattern.<init>(Pattern.java:1351)
    at java.util.regex.Pattern.compile(Pattern.java:1028)

Is there a way to find out where index 1337 is?

Answer 1

In Java, unescaped [ is always considered an open class syntax, never a literal. This is the reason some recommend always escape literal class metachars [ ] which translates across most all engines.

Converting

    [!"#$%&'()*+,\-.\/:;<=>?@[\]^_`{|}~] 
to  [!-/:-@\[\]-`{-~]  

then refactoring the regex.
(Note there may be usability problems with the regex as well.)

Before refactor :

(?:\s+|chiffre|job-id|job-nr[.]|job-nr|\bjob[ ]id\b|job[ ]nr[.]|jobnummer|jobnr[.]|jobid|jobcode|job[ ]nr.|ziffer|kennziffer|kennz.|referenz[ ]code|referenz-code|referenzcode|ref[.][ ]nr[.]|ref[.][ ]id|ref[ ]id|ref[.]id|ref[.]-nr[.]|ref[.]-[ ]nr[.]|referenz[ ]nummer|referenznummer|referenz[ ]nr[.]|stellenreferenz|[ ]referenz-nr[.]|referenznr[.]|referenz|referenznummer[ ]der[ ]stelle|id\#|id[ ]\#|stellenausschreibungen|stellenausschreibungs\s?nr[.]|stellenausschreibungs-nr[.]|stellenausschreibungsnr[.]|stellenangebots[ ]id|stellenangebots-id|stellenangebotsid|stellen[ ]id|stellen-id|stellenid|stellenreferenz|stellen-referenz|ref[.]st[.]nr[.]|stellennumer|\bst[.]-nr[.]\b|\bst[.][ ]nr[.]\b|kenn-nr[.]|positionsnummer|kennwort|stellenkey|stellencode|job-referenzcode|stellenausschreibung|bewerbungskennziffer|projekt[ ]id|projekt-id|reference[ ]number|reference[ ]no[.]|reference[ ]code|job[ ]code|job[ ]id|job[ ]vacancy[ ]no[.]|job-ad-number|auto[ ]req[ ]id|job[ ]ref|\bstellenausschreibung[ ]nr[.]\b):?(?:\w*)(?:\s*)([A-Z]*\s*)([!"#$%&'()*+,\-.\/:;<=>?@\[\]^_`{|}~]*(?:\w*[!"#$%&'()*+,\-.\/:;<=>?@\[\]^_`{|}~]*){3})?

After refactor :

(?:\s+|chiffre|job(?:-(?:id|nr[.]?|referenzcode|ad-number)|[ ](?:(?:nr|vacancy[ ]no)[.]|code|id|ref)|n(?:ummer|r[.])|id|code)|\b(?:job[ ]id|st(?:[.][ \-]|ellenausschreibung[ ])nr[.])\b|(?:bewerbungskenn)?ziffer|kenn(?:z(?:iffer|.)|-nr[.]|wort)|ref(?:eren(?:z(?:[ ](?:code|n(?:ummer|r[.]))|-?code|n(?:ummer|r[.]|ummer[ ]der[ ]stelle))?|ce[ ](?:n(?:umber|o[.])|code))|[.](?:[ ](?:nr[.]|id)|id|(?:-[ ]?|st[.])nr[.])|[ ]id)|stellen(?:referenz|a(?:usschreibung(?:en|s(?:\s?|-)?nr[.])?|ngebots[ \-]?id)|[ ]?id|-(?:id|referenz)|numer|key|code)|[ ]referenz-nr[.]|id[ ]?\#|p(?:ositionsnummer|rojekt[ \-]id)|auto[ ]req[ ]id):?\w*\s*[A-Z]*\s*(?:[!-/:-@\[\]-`{-~]*(?:\w*[!-/:-@\[\]-`{-~]*){3})?

Answer 2

The main problem with the regex is that both [ and ] must be escaped in a character class in a Java regex as these are used to form character class unions and intersections, are "special" there.

Another issue is the [.]\b patterns won't work as expected because a word boundary after a non-word char will require a word char immediately to the right of the current position. You need a \B there, not \b.

You need to escape / char in a Java regex pattern.

You do not have to repeat the pattern at the end of the regex, you may "repeat" it with a limiting {0,3} quantifier after wrapping the repeated pattern with a non-capturing group, (?:...).

Consider a while block to get all matches. You may use a boolean flag to see if there were any matches or not.

Also, you probably want to use \\s+ alternative as the last one in the first group, it is too generic, but I will leave it at the start for the time being.

Use

Pattern pattern = Pattern.compile(""
                + "(?:\\s+|chiffre|job-id|job-nr[.]|job-nr|\\bjob id\\b|job nr[.]|jobnummer|jobnr[.]|jobid|jobcode|job nr\\.|ziffer|kennziffer|kennz\\.|referenz code|referenz-code|"
                + "referenzcode|ref[.] nr[.]|ref[.] id|ref id|ref[.]id|ref[.]-nr[.]|ref[.]- nr[.]|"
                + "referenz nummer|referenznummer|referenz nr[.]|stellenreferenz| referenz-nr[.]|referenznr[.]|referenz|referenznummer der stelle|id#|id #|stellenausschreibungen|" 
                + "stellenausschreibungs\\s?nr[.]|stellenausschreibungs-nr[.]|stellenausschreibungsnr[.]|stellenangebots id|stellenangebots-id|stellenangebotsid|stellen id|stellen-id|stellenid|stellenreferenz|"
                + "stellen-referenz|ref[.]st[.]nr[.]|stellennumer|\\bst[.]-nr[.]\\B|\\bst[.] nr[.]\\B|kenn-nr[.]|positionsnummer|kennwort|stellenkey|stellencode|job-referenzcode|stellenausschreibung|"
                + "bewerbungskennziffer|projekt id|projekt-id|reference number|reference no[.]|reference code|job code|job id|job vacancy no[.]|job-ad-number|auto req id|job ref|\\bstellenausschreibung nr[.]\\B)"
                + ":?\\w*\\s*([A-Z]*\\s*)([!\"#$%&'()*+,\\-./:;<=>?@\\[\\]^_`{|}~]*(?:\\w*[!\"#$%&'()*+,\\-./:;<=>?@\\[\\]^_`{|}~]*){0,3})?");

String line = "Referenznummer: INDUSTRY Kontakt: ZAsdfsdfS Herr Andrafgdh Neue Str. 7 21244 Buchholz +42341 22322 mdjob.bu44lz@zaqusssis.de Stellenanzeige teilen: Jetzt online bewerben! oder bewerben Sie sich mit\n" +
            "Geben Sie bei Ihrer Bewerbung die Stellenreferenz und die Stellenbezeichnung an! \n" +
            "Stellenreferenz:   21533448-JOtest\n\n" +
            "Stellenausschreibung Nr. PD-666/19";


Matcher m = pattern.matcher(line);
boolean found = false;
while (m.find()) {
     found = true;
     System.out.println("Found value: " + m.group(0) );
     System.out.println("Found value: " + m.group(1) );
     System.out.println("Found value: " + m.group(2) );
     System.out.println(" ----------------------- " );
}
if (!found) {
     System.out.println("NO MATCH");
}                 

See this Java demo.