GUI/Inner Classes

Overview

For this homework you will implement an interest calculator. A video of the calculator you need to implement can be found at Video.

Notice that there are no public/release/secret tests associated with this project. In addition, you do not need to provide any student tests.

Objectives

This project is designed to help you develop your skills at defining inner classes and simple GUIs.

Grading

(30%) GUI
- (5%) principal text field
- (5%) rate text field
- (5%) years text field
- (5%) simple interest button
- (5%) compound interest button
- (5%) labels (Principal:, Rate(Percentage):, Years:)
(15%) Correct computation of simple interest
(15%) Correct computation of compound interest
(20%) Non-Anonymous inner class for simple interest button
(20%) Anonymous inner class for compound interest button

Clarifications

Any clarifications or corrections associated with this project will be available at Clarifications.

Code Distribution

For this project we are not providing any code (we just defined a package). We are providing an empty code distribution (available by checking out the project named InterestCalculator) so you can submit your project as usual. Feel free to add any classes/packages you understand you need. To simplify the grading process, make sure you have in the calculator package a class named InterestGUI.java. This class must have a main method that allow us to execute the calculator program.

Specifications

Interest Functions

You need to implement a GUI for a calculator that computes simple and compound interest. The formula to compute simple interest amount is:

simple interest amount = principal + (principal * (rate/100) * years)

The formula to compute compound interest amount is:

Compound Interest Amount = principal * (1 + rate/100)^Years

Notice that you do not need to add the principal in this case.

Displaying Currency

To display currency you can use the NumberFormat class (part of java.text) as follows:

String formattedValue = NumberFormat.getCurrencyInstance().format(value);

where value represents the numeric value to format.

Requirements

Your GUI should resemble the GUI available in the video, but it does not have to be exactly the same.
Keep the Model-View-Control model in mind when writing your code. Feel free to add any classes you understand you need.
You may only use inner classes to define event listeners.
One of your listener objects must be implemented using an anonymous inner class.
One of your listener objects must be implemented using a non-anonymous inner class.
You must attempt to submit your project immediately after checking out the project (even if you have not implemented any methods). This will allow you to verify that the submission process is working as expected.
You should submit your project often. This will keep versions of your project in the submit server that are easy to retrieve (you can also get previous versions from your CVS repository). If your computer crashes or you experience any other problem you will have a permanent backup in the submit server.
No student tests are required for this project.
Style
- Good variable names.
- You must avoid code duplication by calling appropriate methods (rather than cutting and pasting code). You may define your own private utility methods to perform often repeated tasks.
- Style as defined by the Eclipse Format Element option (Source → Format → Format Element) or as specified in Code Conventions for the JavaTM Programming Language (focus on the following sections: Indentation, Declarations, Statements, White Space, and Naming Conventions).
- Although you should avoid source lines exceeding 80 characters, you will not be penalize if they are present in your code.