Class Inheritance Exercises - RadioDatabase

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(reader.readLine());
        RadioDatabase radioDb = new RadioDatabase();


            for (int i = 0; i < n; i++) {
                try {
                    String[] inputTokens = reader.readLine().trim().split(";");
                    String artistName = inputTokens[0];
                    String songName = inputTokens[1];
                    String[] timeTokens = inputTokens[2].trim().split(":");
                    Song song = new Song(artistName, songName, timeTokens);
                    radioDb.addSong(song);

                } catch (Exception ex) {
                    System.out.println(ex.getMessage());
                }
            }
            System.out.println(radioDb);
    }
}

class RadioDatabase {

    private List<Song> playList;
    private int totalTime;

    public RadioDatabase() {
        this.playList = new ArrayList<>();
    }

    public void addSong(Song song) throws NoSuchFieldException, IllegalAccessException {
        this.playList.add(song);
//        Field fieldTimeSeconds = song.getClass().getDeclaredField("timeSeconds");
//        fieldTimeSeconds.setAccessible(true);
        totalTime += song.getTime(); //(int) fieldTimeSeconds.get(song);
        System.out.println("Song added.");
    }

    private List<Song> getPlayList() {
        return this.playList;
    }


    private int getTotalTime() {
        return totalTime;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        int timeSeconds = this.getTotalTime();
        int hours = timeSeconds / 3600;
        timeSeconds %= 3600;
        int minutes = timeSeconds / 60;
        timeSeconds %= 60;
        int seconds = timeSeconds;
        sb.append(String.format("Songs added: %s%n", this.getPlayList().size()));
        sb.append(String.format("Playlist length: %sh %sm %ss", hours, minutes, seconds));
        return sb.toString();
    }

}

class Song {
    private String artistName;
    private String songName;
    private int timeSeconds;

    public Song(String artistName, String songName, String[] timeTokens) {
        this.setArtistName(artistName);
        this.setSongName(songName);
        this.setTime(timeTokens[0], timeTokens[1]);
    }

    public int getTime() {
        return this.timeSeconds;
    }

    private void setTime(String minutes, String seconds) {
        if (minutes == null || seconds == null) {
            throw new InvalidSongLengthException(InvalidSongLengthException.INVALID_SONG_LENGTH);
        }

        int minutesInt = Integer.parseInt(minutes);
        int secondsInt = Integer.parseInt(seconds);

        if (minutesInt < 0 || minutesInt > 14) {
            throw new InvalidSongLengthException(InvalidSongLengthException.INVALID_SONG_MINUTES);
        }

        if (secondsInt < 0 || secondsInt >= 60) {
            throw new InvalidSongLengthException(InvalidSongLengthException.INVALID_SONG_SECONDS);
        }
        this.timeSeconds = (minutesInt * 60) + secondsInt;
    }


    private void setArtistName(String artistName) {
        if (artistName == null) {
            throw new InvalidSongException(InvalidSongException.INVALID_SONG);
        }

        if (artistName.length() <= 3 || artistName.length() >= 20) {
            throw new InvalidSongException(InvalidSongException.INVALID_ARTIST_NAME);
        }
        this.artistName = artistName;
    }

    public void setSongName(String songName) {
        if (songName == null) {
            throw new InvalidSongException(InvalidSongException.INVALID_SONG);
        }

        if (songName.length() <= 3 || songName.length() >= 30) {
            throw new InvalidSongException(InvalidSongException.INVALID_SONG_NAME);
        }
        this.songName = songName;
    }
}

class InvalidSongException extends IllegalArgumentException {

    public static final String INVALID_SONG = "Invalid song.";
    public static final String INVALID_ARTIST_NAME = "Artist name should be between 3 and 20 symbols.";
    public static final String INVALID_SONG_NAME = "Song name should be between 3 and 30 symbols.";

    public InvalidSongException(String message) {
        super(message);
    }
}

class InvalidSongLengthException extends InvalidSongException{
    public static final String INVALID_SONG_LENGTH = "Invalid song length.";
    public static final String INVALID_SONG_MINUTES = "Song minutes should be between 0 and 14.";
    public static final String INVALID_SONG_SECONDS = "Song seconds should be between 0 and 59.";


    public InvalidSongLengthException (String message) {
        super(message);
    }
}



/*
Input 1:
3
ABBA;Mamma Mia;3:35
Nasko Mentata;Shopskata salata;4:123
Nasko Mentata;Shopskata salata;4:12

Expected output 1:
Song added.
Song seconds should be between 0 and 59.
Song added.
Songs added: 2
Playlist length: 0h 7m 47s


Input 2:
5
Nasko Mentata;Shopskata salata;14:59
Nasko Mentata;Shopskata salata;14:59
Nasko Mentata;Shopskata salata;14:59
Nasko Mentata;Shopskata salata;14:59
Nasko Mentata;Shopskata salata;0:5

Expected output 2:
Song added.
Song added.
Song added.
Song added.
Song added.
Songs added: 5
Playlist length: 1h 0m 1s


 */