SongLibrary

Song library GUI built using JavaFX, Eclipse, and Scenebuilder in Java 8.

Features

• Display a list of songs by name, with the ability to select one song from the list.
  • List data is stored as a file, to persist across multiple sessions.
• Display the details of the selected song: name, artist, year, album.
• Add, Edit, and Delete songs
  • Adding songs requires at least the name and artist, and duplicates are not allowed.
  • Editing songs allows for changing any detail of a song, but cannot have duplicates again.
  • The user is able to delete any song.
  • Every action requests confirmation from the user before making the final changes.

Song list implementation

The song list is implemented with a ListView, a parameterized JavaFX class that allows for the user to select an item from the list. In order to have song details update on every click, the ListView is wrapped in an ObservableList, which allows for setting an event handler on the selection change using Java 8's lambda expressions.

//SongController.java
showSongDetails();
    
//Set listener for selection changes
songList.getSelectionModel().selectedItemProperty().addListener(
        (obs, oldValue, newValue) -> showSongDetails());

...

public static int findIndex(ObservableList<Song> list, Song s){
    int i;
    for(i = 0; i < list.size(); i++){
        if(list.get(i).compareTo(s)==0){
            return -1; //implies an error, song already found
        }
        else if(list.get(i).compareTo(s)>0){
            return i; //take position in list
        }
        else{
            // (list.get(i).compareTo(s)<0)
            continue; //keep iterating for a spot
        }
    }
    // (i == list.size()-1)
    return i;//Append to end of list
}

Song Class

The Song class implements the Comparable interface to allow for sorting the song list alphabetically, as well as finding the index position of a song by overriding the compareTo method.

//Song.java

@Override
public int compareTo(Song s) {
    if(this.title.trim().toUpperCase().compareTo(s.getTitle().trim().toUpperCase()) == 0){
        if(this.artist.trim().toUpperCase().compareTo(s.getArtist().trim().toUpperCase()) == 0){
            return 0;
        }
        else if(this.artist.trim().toUpperCase().compareTo(s.getArtist().trim().toUpperCase()) > 0){
            return 1;
        }
        else{
            return -1;
        }
    }
    else if(this.title.trim().toUpperCase().compareTo(s.getTitle().trim().toUpperCase()) > 0){
        return 1;
    }
    else{
        return -1;
    }
}

Saving files

List persistence was implemented by creating a songs.txt file in the data directory to read and write from. We chose to use a PrintWriter to write to the file, and add each detail as a separate line to read from. By setting a simple counter, we break the file into chunks of 4 to load as songs into the ObservableList. Using the FXCollections.sort() function allows for alphabetical sorting regardless of when a song is inputted.

Reading from file:

//SongController.java
File data = new File("src/data/songs.txt");
obsList = FXCollections.observableArrayList();
if(data.exists() && !data.isDirectory()){
    try {
        Scanner fileIn = new Scanner(data);
        
        int lines = 0;
        while (fileIn.hasNextLine()) {
            lines++;
            fileIn.nextLine();
        }
        fileIn.close();
        fileIn = new Scanner(data);
        lines -= 2;
        fileIn.nextLine();
        fileIn.nextLine();
        if(lines%4 == 0){
            for(int i=0; i<lines; i+=4){
                obsList.add(new Song(fileIn.nextLine(), fileIn.nextLine(), fileIn.nextLine(), fileIn.nextLine()));
            }
            /*
                * The Following should work
                * using the compareTo method in song
                * https://docs.oracle.com/javase/8/javafx/api/javafx/collections/FXCollections.html
                */
            FXCollections.sort(obsList);
        }
        else{
            Alert alert = new Alert(AlertType.WARNING);
            alert.setTitle("WARNING");
            alert.setHeaderText("File Error");
            alert.setContentText("Formatting of file is not modulus 4");
            alert.showAndWait();
        }
        
        fileIn.close();
        
    } catch (FileNotFoundException e) {
        Alert alert = new Alert(AlertType.WARNING);
        alert.setTitle("WARNING");
        alert.setHeaderText("File Error");
        alert.setContentText("File does not exist");
        alert.showAndWait();
        e.printStackTrace();
    }
    
}

Writing to file

When the program is closed, it will automatically write to file what songs you have in your list.

//SongController.java

//Write to file when program is closed
primaryStage.setOnCloseRequest(event -> {
    PrintWriter write;
    try {
        File file = new File("src/data/songs.txt");
        file.createNewFile();
        write = new PrintWriter(file);
        write.println("Messing with song file format will result");
        write.println("IN LOSING ALL YOUR SONGS");
        for(int i = 0; i < obsList.size(); i++) {
            write.println(obsList.get(i).getTitle());
            write.println(obsList.get(i).getArtist());
            write.println(obsList.get(i).getAlbum());
            write.print(obsList.get(i).getYear());
            if(i != obsList.size()-1){
                write.println("");
            }
        }
        write.close();
        
    } catch (Exception e) {
        e.printStackTrace();
    }
});
titleAddField.setText("");
artistAddField.setText("");
albumAddField.setText("");
yearAddField.setText("");
}