RegExTest.java Source code

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Here is the source code for RegExTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
   This program tests regular expression matching.
   Enter a pattern and strings to match, or hit Cancel
   to exit. If the pattern contains groups, the group
   boundaries are displayed in the match.
   @version 1.01 2004-05-11
   @author Cay Horstmann
*/
public class RegExTest {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter pattern: ");
        String patternString = in.nextLine();

        Pattern pattern = null;
        try {
            pattern = Pattern.compile(patternString);
        } catch (PatternSyntaxException e) {
            System.out.println("Pattern syntax error");
            System.exit(1);
        }

        while (true) {
            System.out.println("Enter string to match: ");
            String input = in.nextLine();
            if (input == null || input.equals(""))
                return;
            Matcher matcher = pattern.matcher(input);
            if (matcher.matches()) {
                System.out.println("Match");
                int g = matcher.groupCount();
                if (g > 0) {
                    for (int i = 0; i < input.length(); i++) {
                        for (int j = 1; j <= g; j++)
                            if (i == matcher.start(j))
                                System.out.print('(');
                        System.out.print(input.charAt(i));
                        for (int j = 1; j <= g; j++)
                            if (i + 1 == matcher.end(j))
                                System.out.print(')');
                    }
                    System.out.println();
                }
            } else
                System.out.println("No match");
        }
    }
}