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Java

Posted by Wolf <null>
Wolf <null>
5,060 Points

KaraokeMachine.java catch exceptions that are not included in the course

I found out that when selecting an artist or a song that is not listed causes an error and stops the program.

Example if we have artists 1-5 or song 1-3 for an artist, and selecting a number higher or a letter = crash

Haven't figured out how to catch the exceptions. Help would be grateful.

This is the code for artist/song options:

public void run() {
    String choice = "";
    do {
        try {
            choice = promptAction();
            switch (choice) {
                case "add":
                    Song song = promptNewSong();
                    mSongBook.addSong(song);
                    System.out.printf("%s added! %n%n", song);
                    break;
                case "choose":
                    String singerName = promptForSingerName();
                    String artist = promptArtist();
                    Song artistSong = promptSongForArtist(artist);
                    SongRequest songRequest = new SongRequest(singerName, artistSong);
                    if (mSongRequestQueue.contains(songRequest)) {
                        System.out.printf("%n%n Whoops %s already requested %s!%n",
                                singerName,
                                artistSong);
                        break;
                    }
                    mSongRequestQueue.add(songRequest);
                    System.out.printf("You chose: %s %n", artistSong);
                    break;
                case "play":
                    playNext();
                    break;
                case "quit":
                    System.out.println("Thanks for singing!");
                    break;
                default:
                    System.out.printf("Unknown choice: '%s'. Try again. %n%n%n",
                            choice);
            }
        } catch (IOException ioe) {
            System.out.println("Problem with input");
            ioe.printStackTrace();
        }
    } while (!choice.equals("quit"));
}

   private String promptArtist() throws IOException {
    System.out.println("\nAvailable artists, choose a number:");
    List<String> artists = new ArrayList<>(mSongBook.getArtists());
    int index = promptForIndex(artists);
    return artists.get(index);
}

private Song promptSongForArtist(String artist) throws IOException {
    List<Song> songs = mSongBook.getSongsForArtist(artist);
    List<String> songTitles = new ArrayList<>();
    for (Song song : songs) {
        songTitles.add(song.getTitle());
    }
    System.out.printf("\nAvailable songs for %s: %n", artist);
    int index = promptForIndex(songTitles);
    return songs.get(index);
}

private int promptForIndex(List<String> options) throws IOException {
    int counter = 1;
    for (String option : options) {
        System.out.printf("%d.) %s %n", counter, option);
        counter++;
    }
    System.out.print("Your choice:  ");
    String optionAsString = mReader.readLine();
    int choice = Integer.parseInt(optionAsString.trim());
    return choice - 1;
}

1 Answer

Wolf <null>
Wolf <null>
5,060 Points
Wolf <null>
Wolf <null>
5,060 Points

Have figured out that one needs to try and catch with IndexOutOfBoundsException, but can't figure out where one should put it.