COMP167 Laboratory 4 -- Classes and ArrayLists

As with Lab2, you will complete a simple mock mp3 player in this lab. The first step will be to create two classes that will enable you to manipulate the song data. I have the code for the GUI so if you implement the classes according to the specification, your entire application will work.

Classes:

1. Start off by creating empty Song and Playlist classes.

2. Add the properties in both classes and stubs for all the required methods/behaviors.

3. Complete the Song class

4. Complete the PlayList class

5. Complete Problems 1 -- 6 in the Mp3Controller class. In some cases, you will have to uncomment lines of code.

Song -- This class will consist of the following properties: title:String, artist:String and duration:int (Note: duration represents the length of the song in seconds). Use data encapsulation for your class and create these additional methods:

• A no-arg constructor that simply initializes all string properties to null and numeric properties to 0.

• A constructor that includes a formal parameter for each instance variable in the class.

• A method named toString() that has no parameters that returns a string containing all the property values separated by a newline char ('\n') - E.g. "Respect\nAretha Franklin\n182".

Playlist -- This class will consists of the following properties: name:String, songs:ArrayList<Song> and creationDate: Calendar. Use data encapsulation for your class and create these additional methods:

• A no-arg constructor that instantiates the ArrayList, initializes the creationDate to the current date and initializes name to null.

• readPlayList(inputFile : File):void reads a playlist in from a file in the following format:

  • name

  • mm/dd/yyyy //creation date

  • song 0 title

  • song 0 artist

  • song 1 duration

  • ...

Note: there should be a newline character after the last duration value.

• getSong( index:int) : Song -- Returns the song stored at location index in the ArrayList.

• setSong(index:int, song:Song):void -- set the song at location index equal to the given Song object. Your code must confirm that the given index is in the range of locations currently in the ArrayList.

• addSong(song:Song) -- adds the given Song object to the end of the ArrayList (otherwise return null).

• removeSong(index:int):Song -- remove the song at location index and return it as the method return value. Confirm that the given index is in the range of locations currently in the ArrayList (otherwise return null).

• setCreationDate() : void -- sets creation date to be current date and time.

• setCreationDate( month:int, day:int, year:int):void - set creation equal to the given date.

• getCreationDateString():String -- return the creation date as a string.

• writePlayList(outputFile : File):void -- writes the playlist out in the format described in the readPlayList method. You should be able to use the PlayList toString() method to implement this operation.

• size():int -- returns the number of Songs in the playlist.

• clearPlayList():void -- clears the playlist of all songs and resets the other fields to the same values used in the constructor.

• toString() -- return a string containing the playlist name, creationDate, list of songs. Use '\n' to separate the playlist fields and the songs (Note: your method should call the toString() method from Song to append the Song information.

Grading:

• Complete the Song class (5 total points)

• Have your code to load the songs from the song file into the ListView control (18 total points)

• Save an updated PlayList to a file (25 total points)