HW #7 Online Book Store Solution



In this assignment, you will implement a few classes needed for an online bookstore software system.

Important: Some of the instructions in this assignment are deliberately vague. In these cases, you are expected to consider the scenario and make appropriate choices.


To complete this part of the assignment, you must complete three classes: Customer, Book, and Main. You must implement these three classes exactly as described in this document. All the code you write should have complete and appropriate comments.

Customer Class [25%]

An instance of this class contains all the information about a single customer. It should have the following attributes stored in its instance variables:

  • customer name

  • customer account ID

  • customer address

  • customer credit card number

  • customer password

  • an array of Book objects that this customer buys
  • a count of how many books this customer has bought. (This will tell you how many cells in the Book array are currently being used.)

The Customer class should support the following actions (methods):

  • Print a summary of the customer’s information to the console. This is the only method in Customer that should print to the console. Don’t print the credit card number and the password.

A getter method to get the customer’s address

A getter method to get the customer’s ID.

A getter method to get the customer’s name.

A getter method to get the credit card number.

A getter method to get the password.

A setter method to set/change the password.

A setter method to set/change the address

A setter method to set/change the credit card number.

A constructor for your Customer class. The constructor should set the customer’s name and address and ID. The constructor should also initialize the array of Book objects to an empty array by setting all the entries to null and setting the number of purchases to zero. You can assume that no customer ever buys more than five hundred books, so it’s safe to use an array of length 500. You should not need to add any parameters to the constructor to initialize the Book array or for the number of book purchases.

A method to add a given Book to the array of books that the customer has bought. This method should also update the numPurchases instance variable appropriately. The customer can buy the same book more than once. The customer can also buy one or more copies of the same book at one time. Add one item to Book array for each copy.

Book Class [30%]

An instance of this class contains all information about a book that the store carries.

It should have the following attributes stored in its instance variables:

  • Book ID number

Book title

Book author

Book publisher

Year of publication

A count of how many copies of this book the store currently has in stock

A count of how many copies of this book the store has sold so far

Book price

The Book class should support the following actions (methods):

Print a summary of the book’s information to the console.

A getter for each instance variable

A method that records the sale of this book to a given Customer. This method should also take the number of requested copies as a parameter. The inventory information should be updated and the Customer’s book array should also be updated. However, if there are none of this book in stock or the number of copies requested is greater than the number available, then this method should make no changes to the values of the instance variables and print an appropriate error message for each case to the terminal instead. If the number of books to buy is negative, print an appropriate error.

A constructor that sets the ID number, amount in stock, title, author, publication year, and price according to arguments required by the constructor. The number sold should be set to an appropriate initial value.

A method that is called when the store (re)stocks the book. The method should increase the number of available copies of the book by the amount given. Print an appropriate error message to the console if the given number of books is less than one.

Main Class [15%]

This class will be used to test the code written for the Book and Customer classes. It should contain only a single, static main method that creates multiple instances of both Book and Customer classes with made-up values of your choice. The main method should also call various methods on these objects to provide what you believe is a complete test of all the functionality therein. If you wish, you may add a few more “get” methods for Book and Customer classes to support this.

UML Diagram [15%]

Create a UML diagram that accurately reflects your completed source code. Don’t forget about access (public/private) and the relationships between the classes. This diagram must be an electronic image file or PDF file. The Engineering build contains two different software tools capable of creating UML diagrams: Dia and Visio. Both of these tools can export the diagram you draw as an image. You can also use another program of your choice (Word, PowerPoint, etc), or you can hand draw the diagram and scan the result to acquire a file you can turn in. Your diagram will be graded on both accuracy and overall neatness.

Additional Enrichment

You are welcome to add additional functionality to your program as you desire. Some suggestions:

Create a new class called Accounting that tracks the sales of the bookstore. Accounting should track the store current bank balance. The Customer and Book classes should use Accounting in some of their methods.

Create a GUI using Java’s FX or Swing library that allows the user to use your Book and Customer classes.

Code Quality [15%]

A good computer program not only performs correctly, it is also easy to read and understand:

  • A comment at the top of the program includes the name of the program, a brief statement of its purpose, your name, and the date that you finished the program.
  • The comment header should also include a list of known bugs or deficiencies, or a statement that the program has no known deficiencies.
  • Variables have names that indicate the meaning of the values they hold.
  • Code is indented consistently to show the program’s structure.
  • The body of if and else clauses are enclosed in braces and indented consistently, even if they consist of only a single line of code.
  • Opening braces are placed consistently, either at the end of a statement or on a line by itself directly after it.
  • Within the code, major tasks are separated by a blank line and prefaced by one or more single-line comments identifying the task.
  • Methods are separated by blank lines and prefaced by a multi-line comment describing what they do and what their parameters mean.
  • Very long statements (such as long print statements or complex boolean expressions) are broken across lines and indented to show their structure.
  • Now that you are familiar with loops and methods, your code should not contain redundant or repeated sections.
  • Your program does not contain extraneous or commented out code. It does not contain out-of-date or irrelevant comments.
  • When a constant value is used repeatedly in your program, declare a final variable with a descriptive name to contain that value. Use it instead of a literal.

Logistics and Hints

  • No starter code for this assignment. Create your own classes.

Hint: Use the Main class to your advantage by writing it bit-by-bit as you write the other two classes. For example, each time you write a new method in Book or Customer, add some code to your Main that calls that method. Don’t wait until the other two classes are finished.

Turning in this Assignment

You are responsible for turning in your homework assignments properly.

Be sure your name is in the comment header at the top of your .java files.

Remember to include comments to remind yourself and your reader the functionality of the different parts of your program.

If you did any of the Additional Enrichment (above), carefully document this functionality in the comment header at the top of your .java files.

Zip up your entire BlueJ project folder and submit the zip file via Moodle.

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