regextestharness2.java

it contains the practical programs in our college

import java.io.Console;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.regex.PatternSyntaxException;

public class RegexTestHarness2 {

    public static void main(String[] args){
        Pattern pattern = null;
        Matcher matcher = null;

        Console console = System.console();
        if (console == null) {
            System.err.println("No console.");
            System.exit(1);
        }
        while (true) {
            try{
                pattern = 
                Pattern.compile(console.readLine("%nEnter your regex: "));

                matcher = 
                pattern.matcher(console.readLine("Enter input string to search: "));
            }
            catch(PatternSyntaxException pse){
                console.format("There is a problem with the regular expression!%n");
                console.format("The pattern in question is: %s%n",pse.getPattern());
                console.format("The description is: %s%n",pse.getDescription());
                console.format("The message is: %s%n",pse.getMessage());
                console.format("The index is: %s%n",pse.getIndex());
                System.exit(0);
            }
            boolean found = false;
            while (matcher.find()) {
                console.format("I found the text \"%s\" starting at " +
                   "index %d and ending at index %d.%n",
                    matcher.group(), matcher.start(), matcher.end());
                found = true;
            }
            if(!found){
                console.format("No match found.%n");
            }
        }
    }
}