PROJECT: JxMusic

Overview

JxMusic is for those who prefer to use a desktop app for listening to music. More importantly, JxMusic is optimized for those who prefer to work with a Command Line Interface (CLI) while still having the benefits of a Graphical User Interface (GUI).

Summary of contributions

  • Code contributed

  • Major enhancement: Storage component of Jxmusic

    • What it does: Enable the app to save the Library’s Playlist information into JSON file, read from library to initialize library class, and scan all valid mp3 files in the /library folder.

    • Justification: It is important in this application because it allows the user to have their playlists information stored. Furthermore, it loads the library folder’s mp3 files and display them on the track panel.

    • Highlights: This enhancement takes the edge cases into considerations when the library folder is empty or does not exist, it can extract a default library from resource folder of the application.

  • Other Contributions:

    • Minor enhancements: Added Track List Command and Track Search Command, which allow users to navigate the all the tracks available in the library folder, and search tracks using keywords.

    • Contributions to project management：

      • self-assigning issues. #40, #37

      • Contribute to the brainstorming. #24

    • Evidence of helping others:

      • Spotted bugs and edge cases on the track and playlist search command.

      • Found bugs on the Group T12-4’s software. #153

Contributions to the User Guide

Given below are sections I contributed to the User Guide. They showcase my ability to write documentation targeting end-users.

Listing all tracks : track list

Shows a list of all tracks in the library.
Format: track list

Stepping a track : step [coming in v2.0]

Steps forward by default 10 seconds or specified time in seconds.
Format: step [s/SECONDS]

  • SECONDS is the number of seconds to step forward.

  • If SECONDS is negative, the command behaves similar to stepback.

Examples:

  • play t/Some Song
    step
    The track moves forward to 10 seconds later of the track and keeps playing.

  • play t/Some Song
    step s/100
    Stepping forward 100 seconds.

  • play t/Some Song
    stop s/-100
    Using negative value for SECONDS will apply the same behaviour as stepback. The track steps backward 100 seconds.

Stepping back : stepback [coming in v2.0]

Steps back by default 10 seconds or specified time in seconds.
Format: stepback [s/SECONDS]

  • SECONDS is the number of seconds to step backward.

  • If SECONDS is negative, the command behaves similar to step.

Examples:

  • play t/Some Song
    stepback
    The track moves backward 10 seconds earlier of the track and keeps playing. If the track has just played for less than 10 seconds, the track replays.

  • play t/Some Song
    stepback s/100
    Stepping back 100 seconds.

  • play t/Some Song
    stepback s/-100
    Using negative value for SECONDS will apply the same behaviour as step. The track steps forward 100 seconds.

Replay a track : replay [coming in v2.0]

Replays a track before the track ends to start from the beginning.
Format: replay

Examples:

  • play t/Some Song
    seek t/100
    replay
    The track plays from the beginning.

Skipping to the next track : next [coming in v2.0]

Plays the next track.
Format: next

Examples:

  • play p/Favourites
    next
    If the last track is being played, the playlist ends and stops.

  • play t/Some Song
    repeat track
    next
    “Some Song” will replay.

  • play p/Favourites
    repeat playlist
    next
    Go to the next track. Since repeat playlist is on, if it is the last track of the playlist playing, the first track of the playlist will play.

  • play p/Favourites
    shuffle
    repeat playlist
    next
    Go to the next track. Since shuffle and repeat playlist are on, if it is the last track playing, the next shuffled repeat will play.

Skipping to the previous track : prev [coming in v2.0]

Plays the previous track.
Format: prev

Examples:

  • play p/Favourites
    prev
    Plays the previous track. If the current track is first track in playlist, replays the same track since there is no previous track.

  • play t/Some Song
    repeat track
    prev
    “Some Song” will replay.

  • play p/Favourites
    repeat playlist
    prev
    Go to the previous track. Since repeat playlist is on, if it is the first track of the playlist playing, the last track of the playlist will play.

  • play p/Favourites
    shuffle
    repeat playlist
    prev
    Go to the previous track. Since shuffle and repeat playlist are on, if it is the first track playing and there was no previous track, the same track repeats.

Repeatedly playing a track : repeat track [coming in v2.0]

Switches the repeat mode to repeatedly play a single track. The command works even without any track playing. Upon running this command, any subsequent track will be played on repeat.
Format: repeat track

Examples:

  • play p/Favourites
    repeat playlist
    repeat track
    Switches to repeat track mode. The currently playing track will be on repeat.

  • repeat track
    play t/Some Song
    “Some Song” will play on repeat.

  • repeat track
    play p/Favourites
    The first track of the “Favourites” playlist will play on repeat.

Repeatedly playing a playlist : repeat playlist [coming in v2.0]

Switches the repeat mode to repeatedly play a single playlist. The command works even without any playlist playing. Upon running this command, any subsequent playlist will be played on repeat.
Format: repeat playlist

Examples:

  • play p/Favourites
    repeat track
    repeat playlist
    Switches to repeat playlist mode. “Favourites” will play on repeat.

  • repeat playlist
    play p/Favourites
    “Favourites” will play on repeat.

  • repeat playlist
    play t/Some Song
    “Some Song” will play on repeat.

Turning off repeat mode : repeat off [coming in v2.0]

Turns off the repeat mode
Format: repeat off

Examples:

  • play p/Favourites
    repeat playlist
    repeat off
    Switches off repeating mode.

Shuffling a playlist : shuffle [coming in v2.0]

Switches on shuffle mode to play tracks in random order.
Format: shuffle

  • When a playlist is in playback (either playing or paused), shuffle will put the rest of the playlist into random order.

  • shuffle will have no effect when track repeating mode is on.

Examples:

  • shuffle
    play p/Favourites
    “Favourites” will play in random order.

  • play p/Favourites
    repeat playlist
    shuffle
    Subsequent tracks will be played in random order. When all the tracks in the playlist has been played, the next repeat will be shuffled.

  • play p/Favourites
    repeat track
    shuffle
    The track being repeated will continue to play until repeat off only then subsequent tracks will play in random order from the remaining unplayed tracks in the playlist.

Turning off shuffle mode : shuffle off [coming in v2.0]

Turns off the shuffle mode
Format: shuffle off

Examples:

  • play p/Favourites
    shuffle
    shuffle off
    Switches off shuffling mode.

Contributions to the Developer Guide

Given below are sections I contributed to the Developer Guide. They showcase my ability to write technical documentation and the technical depth of my contributions to the project.

ReadLibrary

Current Implementation

The readLibrary is a part of JsonLibraryStorage. It reads the Json file as well as the library folder when initialising the library class. It calls the following operations:

  • JsonFileStorage.loadDataFromFile(filepath) - deserialize the Json file and create library class.

  • Trackscanner.scan(libraryDir) - scan through the library folder and fill all the valid mp3 files into a set of tracks.

No matter whether the Json file exists, trackscanner will run first to make sure the library class contains the tracks set. Then if the file path exists, it will deserialize the json file to initialize library’s playlist information. The deserializer and serializer are programmed with Gson library.

The trackscanner navigates to the library folder and extracts the mp3 files and add them to the set of tracks. However there are cases that the user does not have a library folder in the same directory as the app. To ensure the tracks contained inside the playlist to be valid and navigable, we put a library folder containing default tracks inside the resources folder. Hence, the program first extracts the library folder from the jar file and copy it to the directory. There are two methods that the app copies library to the directory:

  • Case 1: If the MainApp is run using jar file, trackscanner will internally run the unzip command to unzip the jar file. (Warning: This only works if the jar file is opened using Terminal);

  • Case 2: If the MainApp is run using IDE, trackscanner will copy the library folder from resources to the directory;

TrackScannerActivityDiagram
Figure 1. Activity of trackscanner

Design Considerations

Aspect: Choice of media player library

  • Alternative 1 (current choice): Read the Json file from data folder and scan the tracks from library folder at the same time.

    • Pros:

      • Enables the library to initialise with all the available tracks in library folder

    • Cons:

      • The track treeset in the library class will not update again after initialisation.

  • Alternative 2: Do not scan the tracks in readLibrary, scan the library each time the user search for tracks in the library folder.

    • Pros:

      • Lead to the files’ latest status inside the library folder

Future Enhancements

When the user double clicks the jar file it cannot run because the unzipping of jar file is done using process.exec, which requires the user to run the jar file using terminal. This needs to be addressed in future development.

Track search and Track list

Current Implementation

The tracklist and tracksearch commands are implemented to view and filter tracks in the library.

  • Command.TrackListCommand - list all the tracks inside the library

  • Command.TrackSearchCommand - search the desired tracks from library whose name contains any of the argument keywords.

TrackListCommandSequenceDiagram
Figure 2. Sequence of track list command
TrackSearchCommandSequenceDiagram
Figure 3. Activity of track search command

Design Considerations

Aspect: Searching multiple keywords.

  • Alternative 1 (current choice): Combines each search results by each keywords separated by space.

    • Pros:

      • Find tracks that match with any of the keywords

    • Cons:

      • Spaces are not included in the keywords.

  • Alternative 2: consider words as one part of the desired track and show results of the search.

    • Pros:

      • Show more precise results

Aspect: Tracks listed display

  • Alternative 1 (current choice): List the tracks in a new panel separate from playlist panel.

    • Pros:

      • Tracks are more clearly shown.

  • Alternative 2: Show the tracks in the message box

    • Pros:

      • Easier to implement.

    • Cons:

      • Takes up the message box and hence the success message or failing message cannot be seen.

Future Enhancements

Future development can combine the two alternatives so that the user can search with keywords including spaces when they intend to.