Java Requires Chilkat v11.1.0+

Regular Expression with Multiple Matches and Capture Groups

See more Regular Expressions Examples

Demonstrates a regular expression with multiple matches and capture groups for each match.

Note: Chilkat uses PCRE2. See PCRE2 Regular Expressions
Also see: PCRE2 Performance

Chilkat2 Java

import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        String pattern = "Name:\\s+(\\w+)\\s+(\\w+),\\s+Email:\\s+(\\S+)";

        StringBuilder sb = new StringBuilder();
        boolean crlf = true;
        sb.appendLine("Name: John Smith, Email: john.smith@example.com", crlf);
        sb.appendLine("Name: Jack Johnson, Email: jack.johnson@example.com", crlf);
        sb.appendLine("Name: Mary Adams, Email: mary.adams@example.com", crlf);

        System.out.println(sb.getAsString());

        // We have the following string:
        // Name: John Smith, Email: john.smith@example.com
        // Name: Jack Johnson, Email: jack.johnson@example.com
        // Name: Mary Adams, Email: mary.adams@example.com

        JsonObject json = new JsonObject();
        json.setEmitCompact(false);

        int timeoutMs = 2000;
        int numMatches = sb.regexMatch(pattern, json, timeoutMs);
        if (numMatches < 0) {
            // Probably an error in the regular expression.
            // Suggestion: Use AI to help create and/or diagnose regular expressions.
            System.out.println(sb.getLastErrorText());
            return;
        }

        // Examine the matches:
        System.out.println(json.emit());

        // This is the JSON with the match information.
        // See the JSON parsing code below to get the matched capture group values.

        // {
        //   "match": [
        //     {
        //       "group": [
        //         {
        //           "cap": "Name: John Smith, Email: john.smith@example.com",
        //           "idx": 0,
        //           "len": 47
        //         },
        //         {
        //           "cap": "John",
        //           "idx": 6,
        //           "len": 4
        //         },
        //         {
        //           "cap": "Smith",
        //           "idx": 11,
        //           "len": 5
        //         },
        //         {
        //           "cap": "john.smith@example.com",
        //           "idx": 25,
        //           "len": 22
        //         }
        //       ]
        //     },
        //     {
        //       "group": [
        //         {
        //           "cap": "Name: Jack Johnson, Email: jack.johnson@example.com",
        //           "idx": 49,
        //           "len": 51
        //         },
        //         {
        //           "cap": "Jack",
        //           "idx": 55,
        //           "len": 4
        //         },
        //         {
        //           "cap": "Johnson",
        //           "idx": 60,
        //           "len": 7
        //         },
        //         {
        //           "cap": "jack.johnson@example.com",
        //           "idx": 76,
        //           "len": 24
        //         }
        //       ]
        //     },
        //     {
        //       "group": [
        //         {
        //           "cap": "Name: Mary Adams, Email: mary.adams@example.com",
        //           "idx": 102,
        //           "len": 47
        //         },
        //         {
        //           "cap": "Mary",
        //           "idx": 108,
        //           "len": 4
        //         },
        //         {
        //           "cap": "Adams",
        //           "idx": 113,
        //           "len": 5
        //         },
        //         {
        //           "cap": "mary.adams@example.com",
        //           "idx": 127,
        //           "len": 22
        //         }
        //       ]
        //     }
        //   ]
        // }

        // Important:  Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

        String cap = "";
        int i = 0;
        int matchCount = json.sizeOfArray("match");
        while (i < matchCount) {
            System.out.println("Match " + (i + 1) + ":");
            json.setI(i);
            int j = 0;
            int numCaptureGroups = json.sizeOfArray("match[i].group");
            while (j < numCaptureGroups) {
                json.setJ(j);
                cap = json.stringOf("match[i].group[j].cap");
                System.out.println(j + ": " + cap);
                j = j + 1;
            }

            i = i + 1;
        }

        // Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

        // Output

        // Match 1:
        // 0: Name: John Smith, Email: john.smith@example.com
        // 1: John
        // 2: Smith
        // 3: john.smith@example.com
        // Match 2:
        // 0: Name: Jack Johnson, Email: jack.johnson@example.com
        // 1: Jack
        // 2: Johnson
        // 3: jack.johnson@example.com
        // Match 3:
        // 0: Name: Mary Adams, Email: mary.adams@example.com
        // 1: Mary
        // 2: Adams
        // 3: mary.adams@example.com
    }
}