JAVA EE: How to use comments flag | Java Regex | Java Regular Expressions

Tuesday 9 January 2018

How to use comments flag | Java Regex | Java Regular Expressions | Regex in java

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RegexDemo.java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**
 * 
 * Flags
 *
 */

public class RegexDemo

{

    public static void main(String[] args)

    {

        /*
         * Pattern.COMMENTS
         * 
         * when we use the flag, it will ignore the extra spaces and
         * the every text starting with # will be seen as a comment to
         * be ignored for each line:
         */

        calculateMatches("dog$  #check end of text", "This is a dog",

                Pattern.COMMENTS);

    }

    private static void calculateMatches(String regex, String inputText,

            int flag)

    {

        Pattern pattern = Pattern.compile(regex, flag);

        Matcher matcher = pattern.matcher(inputText);

        int matches = 0;

        /*
         * The find method keeps advancing through the input text and
         * returns true for every match, so we can use it to find the
         * match count as well:
         */

        while (matcher.find())

        {

            ++matches;

        }

        System.out.println("Number of Matches = " + matches);

    }

}