Java Invoice Exercise

As a software developer, you are likely to be part of a software development team. Being able to divide a project up and work well with others are important skills. Collaboration at a distance can be challenging but is becoming more common. This task will give you experience to collaborate on a software development project with a partner who is not on site.

Task

Note: To complete this task, you will need the latest Java SE Development Kit (JDK). This includes the Java Runtime Environment (JRE) and command line development tools that are useful for developing applets and applications. It is recommended that you complete this assignment using NetBeans Integrated Development Environment. To download this program, see the web link below.

Write an application that does the following:

• Creates class Invoice
• Declares class member variable called numberOfInvoices that is incremented each time a new invoice is created
• Declares the four following instance member variables:
  • companyName (which stores String representing name of Company)
  • amountDue of type double
  • chargeDate of type String
  • invoiceNumber of type int where invoiceNumber is initialized to ++numberOfInvoices
• Makes all member variables private to hide and encapsulate data
• Implements the four following public getters to retrieve current values of all private members:
  • getCompanyName()
  • getAmountDue()
  • getChargeDate()
  • getInvoiceNumber()
• Implements the three following public setters to set values of all private members:
  • setCompanyName(String coName)
  • setAmountDue(double Amount)
  • setChargeDate(String dateCharged)
• Creates required public constructors, including one that uses all setters to initialize all private attributes: companyName, amountDue, and chargeDate
• Implements class (static) method getNumberOfInvoices() to return numberOfInvoices

Write a test application that does the following to create three Invoices to test the class developed in part A:

• Creates an instance of Invoice and uses the Invoice constructor to initialize the following private attributes: companyName is “Amazing Software”, amountDue is “5,000.00”, and chargeDate is “January 18, 2009”
• Creates an instance of Invoice and uses the Invoice constructor to initialize the following private attributes: companyName is “Best Programs”, amountDue is “4,000.00”, and chargeDate is “February 18, 2009”
• Creates an instance of Invoice and uses the Invoice constructor to initialize the following private attributes: companyName is “Champion Code”, amountDue is “3,000.00”, and chargeDate is “March 18, 2009”
• Uses class method getNumberOfInvoices() to get and print class member variable called numberOfInvoices without instantiating another Invoice

When finished with your application, evaluate your programmed solution and discuss the following questions with your partner:

• What techniques did you use for information hiding and encapsulation? Are there any improvements you would make? If so, what would they be?
• Which members were instance members? Did you have any class members?
• What would the result be if you made numberOfInvoices a final variable?