Repetative capturing group matches only last occurence

Question

Following text data given i am experiencing strange capturing group behavior. When i try to iterate over all tables only the last row of data. Is there a way to maintain all capturing groups not only the last row (values of each table)?

I am using this pattern (?<tabname>\S+)\n\=*\n(?:(\d+)\ *\|\ *(\d+)\n)+

TABLE1
=======
1  | 2
15 | 2
3  | 15

TABLE2
=======
3  | 5
12 | 2
17 | 7

---

Edit: Sorry for my inconsistent question, here my expected and actual outputs:

Expected output would be:

Match 1 of 2:

Group "tabname":    TABLE1
Group 2:    1
Group 3:    2
Group 4:    15
Group 5:    2
Group 6:    3
Group 7:    15

Match 2 of 2:

Group "tabname":    TABLE2
Group 2:    3
Group 3:    5
Group 4:    12
Group 5:    2
Group 6:    17
Group 7:    7

But actual output is:

Match 1 of 2:

Group "tabname":    TABLE1
Group 2:    3
Group 3:    15

Match 2 of 2:

Group "tabname":    TABLE1
Group 2:    17
Group 3:    7

Answer 1

I believe you can use this regex

(?s)(?:(TABLE\d+)|\G)(?:(?!TABLE).)+?(\d+)\s+\|\s+(\d+)

Regex Demo

With a bit of Java help, you can achieve the result

String line = "TABLE1\n=======\n1  | 2\n15 | 2\n3  | 15\n\nTABLE2\n=======\n3  | 5\n12 | 2\n17 | 7";
String pattern = "(?s)(?:(TABLE\\d+)|\\G)(?:(?!TABLE).)+?(\\d+)\\s+\\|\\s+(\\d+)";
Pattern r = Pattern.compile(pattern);
Matcher m = r.matcher(line);
int flag = 0;

while (m.find()) {
    if (m.group(1) != null) {
        flag = 0;
    }

    if (flag == 0) {
        System.out.println(m.group(1) + "\n" + m.group(2) + "\n" + m.group(3));
        flag = 1;
    } else {
        System.out.println(m.group(2) + "\n" + m.group(3)); 
    }
}

Ideone Demo

Answer 2

You can collect your data in 2 passes. The first regex will just match the tables with all the values:

"(?<tabledata>\\S+)\\s+\\S+(?<vals>[|\\d\\s]+)"

See demo. Next, we'll just match the numbers and add them to the string array (with the simple \d+ regex).

Here is a full Java demo producing [[TABLE1, 1, 2, 15, 2, 3, 15], [TABLE2, 3, 5, 12, 2, 17, 7]]:

import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        String s = "TABLE1\n=======\n1  | 2\n15 | 2\n3  | 15\n\nTABLE2\n=======\n3  | 5\n12 | 2\n17 | 7"; 
        Pattern pattern = Pattern.compile("(?<tabledata>\\S+)\\s+\\S+(?<vals>[|\\d\\s]+)");
        Matcher matcher = pattern.matcher(s);
        List<List<String>> res = new ArrayList<>();
        while (matcher.find()){
            List<String> lst = new ArrayList<>();
            if (matcher.group("tabledata") != null) {
                lst.add(matcher.group("tabledata"));
            }
            if (matcher.group("vals") != null) {
                Matcher m = Pattern.compile("\\d+").matcher(matcher.group("vals"));
                while (m.find()) {
                    lst.add(m.group(0));
                }
            }
            res.add(lst);
        } 
        System.out.println(res); 
    }
}