General planning implementation tasks of Managing Play Lists in Chinook

[apalavecinofrez]

This task list area will be completed once the implementation plan has been outlined. This area is where one creates the task list associated with the milestone.

• [ ] Create Data Models
• Create Query Models
  • [ ] TrackSelectionView
  • [ ] PlaylistTrackView
• Create Command Models
  • [ ] MoveTrackCommand
• [ ] Create Transactional Services (methods)
  • [ ] Add track (AddTrack)
  • [ ] Remove tracks from playlist (RemvoeTracks)
  • [ ] Reorganize playlist tracks (MoveTracks)
  • [ ] #4

[apalavecinofrez]

UI Experience

This comment outlines the actions that can happen to the forms. Actions are in response to the user interacting with the form, pressing buttons, or controls.

PRG Post Redirect Get (Query)

• Using routing parameters {searchtype?}/{searchvalue?}/{playlistname?}
• PRG clicking the Clear empties bound properties and routing parameters (page only)
• PRG clicking the Fetch will retrieve the existing playlist for the specified playlist name {playlistname?}
• PRG clicking the Fetch Artist tracks or Fetch Album tracks will be retrieved the tracks for the indicated search and display in a table {searchtype?}/{searchvalue?}
• Post/PRG clicking the Add [+] on the track will attempt to add a track to the playlist: <<<???>>>
  • rule: unique track on the playlist
  • rule: playlist name needs to be unique for user
  • rule: appended track to the playlist
• Post/PRG clicking the Remove Track will attempt to remove 1 or more tracks from the playlist: <<<???>>>
  • rule: re-sequence the playlist track number leaving no gaps
• Post/PRG clicking the Re-Org Tracks will reorder the tracks based on the values that are placed in the edit box.

  • rule: Re-order numbers must be unique and within the range of the current tracks.

    Managing the playlist

[apalavecinofrez]

Data Model

The data models are C# classes that we will be coding in the folder (ViewModel) that holds the data classes in our solution. These classes represent the query class models and the command class model (CQRS - Command and Query Responsibility Segregation)

---

Query Models

Artist and Album Tracks fetch

Tracks -> TrackID Tracks -> SongName

public class TrackSelectionView
{
  public int TrackId {get; set;}
  public string SongName {get; set;}
  public string AlbumTitle {get; set;}
  public string ArtistName {get; set;}
  public int Milliseconds {get; set;}
  public decimal Price {get; set;}
}

Current Playlist Tracks

public class PlaylistTrackView
{
  public int TrackId {get; set;}
  public int TrackNumber {get; set;}
  public string SongName {get; set;}
  public int Milliseconds {get; set;}
}

---

Command Model

Add Track

No model class, individual paramaters

public string AddTrack(string userName, string playlistName, int trackId)

Remove Tracks

No model class, individual paramaters

public string RemoveTrack(int playlistId, list<int> trackIds)

---

Move Tracks

public class MoveTrackCommand
{
  public int TrackId {get; set;}
  public int TrackNumber {get; set;}
}

[apalavecinofrez]

Business Processing Requirements

This comment will describe the various methods that will be used for commands (CRQS) that alter the database. Queries are read-only and required, on average, no complex processing. You may in another comment, outline your query methods. However, commands require business rules, data validation and manipulations of one or more tables and/or records. Therefore, the processing of commands could require extensive logic to be outlined.

Include the methods signature and a bullet list of processing (pseudo-code)

Add Track

void PlaylistTrackService_AddTracks(string userName, string playlistName, int trackId)

• check if the incoming data is completed (all parameter exists)
  • if a problem exists, throw an ArgumentNullException for missing incoming values
• check that track exists
  • if it does not exist, throw an ArgumentException on the trackID
• check to see if playlist exists
  • no (new playlist)
  • create a new playlist record
  • set the track number to 1
  • yes (appending to existing playlist)
  • check if the track already exists on the playlist
    • yes
    • throw an exception that track already exists
    • no
    • determine the next track number
  • add track to playlist tracks
  • check for any errors
  • yes: throw the list of all collected exceptions
  • no: save all work to the database

---

Remove Track(s)

void PlaylistTrackService_RemoveTracks(int playlistID, list \<int> trackIds)

• check if the incoming data is completed (all parameter exists)
  • if a problem exists, throw an ArgumentNullException for missing incoming values
• check that playlist exists
  • if it does not exist, throw an ArgumentException on the playlistId
  • if it exists
  • for each track to be removed
    • check that the track exists
    • yes: remove the track
    • no: add track id to exceptions
    • for each track in the remaining list
    • re-sequence the tracking number (starting at 1, increment of 1)
    • stage each track for update
• check for any errors
  • yes: throw the list of all collected exceptions
  • no: save all the track to the database.

---

Move Tracks

void PlaylistTrackService_MoveTracks(int playlistId, list \<MoveTrackCommand> moveTracks)

• check if the incoming data is completed (all parameter exists)
  • if a problem exists, throw an ArgumentNullException for missing incoming values
• check that playlist exists
  • if it does not exist, throw an ArgumentException on the playlistId
  • if it exists
  • check tracks to move
    • for each track, check:
    • track number is positive numeric (add any exception)
    • track number is unique (add any exception)
    • for each track
    • re-sequence track number (start 1, increment by 1)
    • stage the update
• check for any errors
  • yes: throw the list of all collected exceptions
  • no: save all the track to the database.