Task: update and submit MusicLibrary.java to Autolab

• DO NOT add new import statements.
• DO NOT change any of the method’s signatures.
• You are allowed to create helper methods if needed, but please ensure they are private (encapsulation!).

The class contains:

• allPlaylists is an ArrayList of Playlist objects
• provided methods that are used by the driver and empty methods you are expected to write your code in.

Note: the printLibrary() method is provided to you and could possibly help with debugging. This method goes through the allPlaylists ArrayList, and prints out the contents of all Playlists that have been added. 

Methods to be implemented by you:  

1. constructPlaylist(String filename)

This method takes the data from an input csv file, and creates a playlist object from it.

To complete this method:

1. Create a new Playlist object
2. Open the file using StdIn.setFile(filename)
3. Declare a LLNode reference that will refer to the last song of the circular linked list
4. Create a counter variable to keep track of the number of songs in the playlist
5. While there are still lines in the input file (remember that StdIn.isEmpty() returns true if every line in the input file has been read):
   1. Read a single song from the file (see the information after these steps for the input file format)
   2. Create a Song object with the information read from the file
   3. Create an LLNode that holds the Song object from step 5.2
   4. Insert the LLNode from step 5.3 to the END of the circular linked list (use the reference from step 3). Remember to update which node is the last node, and also remember that the last node needs to point to the front 
   5. Increase the count of the number of songs already in the circular linked list
6. Return the Playlist object from step 1, that includes both the LLNode object from step 3 (reference to the last node) and the number of songs

If the playlist is empty, return a Playlist object with null in the last field, and 0 as its size.

For step 4.1: Use the StdIn library to read from a file, to read one song do:
String[] data = StdIn.readLine().split(“,”);
String name = data[0];
String artist = data[1];
int year = Integer.parseInt(data[2]);
int pop = Integer.parseInt(data[3]);
String link = data[4];

The input files have songs in decreasing popularity order; so the list should also be kept in this order. DO NOT implement a sorting algorithm, there is no need.

• Submit MusicLibrary.java with just this method completed (others can be blank) under Early Submission to receive 5 points of extra credit.

Use the pre-implemented addPlaylist() method to test this method. Add the playlist at index 0 (to represent this will be the playlist in the first position). This is the expected output for 2010.csv: