Java The Complete Reference, Seventh Edition

Chapter 32: Financial Applets and Servlets 941

double principal; // original principal
double rateOfRet; // rate of return
double numYears; // length of investment in years
int compPerYear; // number of compoundings per year

NumberFormat nf;

public void init() {
try {
SwingUtilities.invokeAndWait(new Runnable () {
public void run() {
makeGUI(); // initialize the GUI
}
});
} catch(Exception exc) {
System.out.println("Can't create because of "+ exc);
}
}

// Set up and initialize the GUI.
private void makeGUI() {

// Use a grid bag layout.

GridBagLayout gbag = new GridBagLayout();

GridBagConstraints gbc = new GridBagConstraints();

setLayout(gbag);

JLabel heading = new

JLabel("Future Value of an Investment");

JLabel amountLab = new JLabel("Principal ");

JLabel periodLab = new JLabel("Years ");

JLabel rateLab = new JLabel("Rate of Return ");

JLabel futvalLab =

new JLabel("Future Value of Investment ");

JLabel compLab =

new JLabel("Compounding Periods per Year ");

amountText = new JTextField(10);

periodText = new JTextField(10);

futvalText = new JTextField(10);

rateText = new JTextField(10);

compText = new JTextField(10);

// Future value field for display only.

futvalText.setEditable(false);

doIt = new JButton("Compute");

// Define the grid bag.

gbc.weighty = 1.0; // use a row weight of 1

gbc.gridwidth = GridBagConstraints.REMAINDER;

gbc.anchor = GridBagConstraints.NORTH;

gbag.setConstraints(heading, gbc);