Matcher groupCount() method in Java with Examples

The java.util.regex.Matcher class represents an engine that performs various match operations. There is no constructor for this class, you can create/obtain an object of this class using the matches() method of the class java.util.regex.Pattern.

The groupCount() method of this (Matcher) class calculates the number of capturing groups in the current match.

Example 1

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class GroupTest {
   public static void main(String[] args) {
      String regex = "(.*)(\\d+)(.*)";
      String input = "This is a sample Text, 1234, with numbers in between.";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Matching the compiled pattern in the String
      Matcher matcher = pattern.matcher(input);
      if(matcher.find()) {
         System.out.println("First group match: "+matcher.group(1));
         System.out.println("Second group match: "+matcher.group(2));
         System.out.println("Third group match: "+matcher.group(3));
         System.out.println("Number of groups capturing: "+matcher.groupCount());
      }
   }
}

Output

First group match: This is a sample Text, 123
Second group match: 4
Third group match: , with numbers in between.
Number of groups: 3

Example 2

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
   public static void main(String[] args) {
      String str1 = "<p>This <b>is</b> an <b>example</b>HTML <b>script</b> where <b>ever</b> alternative <b>word</b> is <b>bold</b></p>.";
      //Regular expression to match contents of the bold tags
      String regex = "(t(\\S+)t)(\\s)";
      String str = "the words tit tat tweet tostff tact that tilt text start and end wit the letter t ";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Matching the compiled pattern in the String
      Matcher matcher = pattern.matcher(str);
      while (matcher.find()) {
         System.out.println(matcher.group(0));
      }
      System.out.println("Total capturing groups: "+matcher.groupCount());
   }
}

Output

tit
tat
tweet
tact
that
tilt
text
tart
Total capturing groups: 3