Song Encryption

package finalExam_16Dec2018;

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

public class P2_SongEncryption {
    public static void main(String[] args) {
        @SuppressWarnings("resource")

        Scanner sc = new Scanner(System.in);

        String line = "";

        String regex = "^(?<artist>[A-Z][a-z'\\s]+):(?<song>[A-Z\\s]+)$";
        Pattern pattern = Pattern.compile(regex);

        while (!"end".equals(line = sc.nextLine())) {
            Matcher matcher = pattern.matcher(line);
            String artist = "";
            String song = "";
            String encrypted = "";

            if (matcher.find()) {
                artist = matcher.group("artist");
                song = matcher.group("song");
            } else {
                System.out.println("Invalid input!");
                continue;
            }

            int key = artist.length();

            for (int i = 0; i < artist.length(); i++) {
                char symbol = artist.charAt(i);
                if (symbol == ' ' || symbol == '\'') {
                    encrypted += symbol;
                    continue;
                }

                if (artist.charAt(i) + key > 'z') {
                    int res = 'z' - artist.charAt(i);
                    symbol = (char) ((key - res) + 'a' - 1);
                    encrypted += symbol;
                } else {
                    symbol = (char) (artist.charAt(i) + key);
                    encrypted += symbol;
                }
            }

            encrypted += '@';

            for (int i = 0; i < song.length(); i++) {
                char symbol = song.charAt(i);
                if (symbol == ' ' || symbol == '\'') {
                    encrypted += symbol;
                    continue;
                }

                if (song.charAt(i) + key > 'Z') {
                    int res = 'Z' - song.charAt(i);
                    symbol = (char) ((key - res) + 'A' - 1);
                    encrypted += symbol;
                } else {
                    symbol = (char) (song.charAt(i) + key);
                    encrypted += symbol;
                }
            }

            System.out.println("Successful encryption: " + encrypted);
        }
    }
}