Description
Program: Inheritance Implementation
Part 1 – DigitalMedia Super Class
Define a super class to model digital media. Sound, images, text and video are all available in digital format for
use on a computer system. The class DigitalMedia is a generalization of these kinds of files. It has four fields:
name(String) is the file name that includes the file extension, size(long) is the file size in bytes.
Design the class so that individual instances never contain null fields. The parameterized constructor must
validate both parameters before creating the instance.
All classes will be graded using a JUnit test suite, so the method headings for all methods need to match the
test class exactly. Refer to the UML diagram to confirm the method headings of your code.
Implement accessor (getter) and mutator (setter) methods for each of the instance variables using the
standard naming conventions. In addition, override the following methods from the Object class:
• public boolean equals(Object other)
• public String toString()
The equals method parameter must be of type Object. Two DigitalMedia objects are equal if they have the
same state as represented by the instance variables. Guidelines for overriding the equals method:
• Use the == operator to check if the argument is a reference to itself.
• Use the instanceof operator to check if the argument has the correct data type– DigitalMedia in this
case.
• Cast the argument to the same data type as the class – DigitalMedia in this case.
• For each significant data member, test for equality.
• Test these three properties:
o Is it symmetric?
o Is it transitive?
o Is it consistent?
Your source code file name should be DigitalMedia.java.
Part 2 – Song and Image Subclasses
Write the following Java subclasses of the DigitalMedia class from Part 1:
• Song to represent a song in a music collection.
o In addition to the inherited instance variables from the super class, there are two additional
data members of the Song class. These are String objects representing the artist’s name
(artist), and the album where the song can be found (album). These instance variables for
the class are to have private access modifiers so you will need to write the appropriate
methods to allow a client to access and modify the data values.
o In accordance with good programming practice, you are to override the equals and toString()
methods inherited from the DigitalMedia class.
§ A Song’s title is the same as the name instance variable in the super class without the
extension.
§ Two Song objects are considered equal if they have the same title, artist, album, and
size.
• Image to represent a digital image file.
o An image has the additional instance variables width and height, both of type int.
o As for the Song class, implement getters, setters, equals, and toString() for the Image class.
Two images are considered equal if they have the same name, size, width, and height
Part 3 – MediaList Class
Implement a class called MediaList that contains a main method that reads in a file name via the command
line. The file is a listing of songs and images. In the file, information about each media item is on a single line.
For Songs, the line is formatted with the letter s, song file name, the artist name, the album, and size in which
each element is separated by a colon (:) and varying amounts of white space. For example,
S : Mykonos.mp3 : Fleet Foxes :Mykonos – Single: 9507904
S : He Doesn’t Know Why.mp3 : Fleet Foxes :Fleet Foxes : 7080711
For Images, the line is formatted with the letter i, the image file name, the width, the height, and size in which
each element is separated by a colon (:) and varying amounts of white space. For example,
I : Beach.jpg : 2048 : 1536 : 1163207
I : IMG_3658.JPG: 2448 : 3264 : 1384318
The MediaList program is to:
• Read in the input file creating Song and Image objects from the data contained in the lines of the file.
Failure to create individual Song/Image objects will result in severe point penalties.
• Store the Songs and Images in a single ArrayList of type DigitalMedia. Using multiple ArrayLists is not
permitted.
• Prompt the user to enter either S or I to see a display of all of the DigitalMedia of that type.
• If “I” is entered, display a formatted list of all the images by calling the toString() method for each
Image object.
• If “S” is entered, display a formatted list of all the songs by calling the toString() method for each Song
object.
Make sure your program is well documented – including the comment block header at the top of all of the
source code files with your name, the course number and name, the project name, the program purpose. Be
sure to include appropriate comments throughout your code, choose meaningful identifiers, and use
indentation as shown in your textbook and in class.
It is expected that your program will be well documented and you are required to include a private helper
method in MediaList.java called printHeading that outputs the following information to the console in an
easy-to-read format: your name, the project number, the course identifier, and the current semester. You will
call this method as the first statement in your main method.
You will upload the project source code files, DigitalMedia.java, Song.java, Image.java, and MediaList.java to
the Assignment link in Blackboard.
CMSC 256 – Project 1
Name: ________________________________________
Part 1 – DigitalMedia class:
Class elements (instance variables, constructor, accessor methods) are correct (5 pts.) _________
equals method written correctly (5 pts.) _________
toString() method written correctly (5 pts.) _________
Class design includes appropriate code to uphold encapsulation (5 pts.) _________
Part 2 – Song and Image Subclasses
Song class:
Class elements (instance variables, constructor, accessor methods) are correct (5 pts.) _________
equals method written correctly (5 pts.) _________
toString() method written correctly (5 pts.) _________
Class correctly implemented as a subclass, using principle of inheritance (5 pts.) _________
Image class:
Class elements (instance variables, constructor, accessor methods) are correct (5 pts.) _________
equals method written correctly (5 pts.) _________
toString() method written correctly (5 pts.) _________
Class correctly implemented as a subclass, using principle of inheritance (5 pts.) _________
Part 3 – MediaList Class
printHeading() method included and called from main() (5 pts.) _________
Reads command line argument for file name (5 pt.) _________
Accurately reads data from file to create objects as specified(10 pt.) _________
All classes:
Code written to anticipate and handle improper data and other errors (10 pt.) _________
Files are named and submitted as specified (5 pts.) _________
Appropriate use of comments (including header comments on all files) (5 pts.) _________
Total (100 pts.) _________
Grading Comments: