Assessment

App.component knows OnAirService that dialogs with AirDDOMonitorServer.

Each track instance is autonomous and subscribes to App.component messages and has one counter instance per track (a playlist_AB thus has two counter instances) as well as a collection of playlist-item instances related to the number cartridge it contains.

The counters and playlist-item trigger the issue of commands, depending on their context (play / pause, stop, selection, d & d etc ...), that the associated track emits through the method sendCommand. Playlist_item also issue commands for chaining change, PFL and loop change.