Create Mortgage Calculator to show how to use JFormattedTextField - Java Swing

Description

Create Mortgage Calculator to show how to use JFormattedTextField

Demo Code

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.ComponentOrientation;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.text.MessageFormat;
import java.text.NumberFormat;
import java.util.Currency;
import java.util.Locale;
import java.util.ResourceBundle;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

/**//  w ww. j a v  a 2 s  .c  o m
 * InternationalizedMortgageCalculator requires the following files:
 * 
 *   resources/Resources_ar.properties
 *   resources/Resources_fr.properties
 *   resources/Resources.properties
 *   
 * It implements a mortgage calculator that uses four JFormattedTextFields.
 */
public class InternationalizedMortgageCalculator extends JPanel implements
        PropertyChangeListener {

    private static JFrame frame;

    protected String newline = "\n";
    protected Action englishUSLocaleAction, englishUKLocaleAction,
            frenchFranceLocaleAction, frenchCanadaLocaleAction,
            arabicSaudiArabiaLocaleAction;

    private static ResourceBundle labels;

    // Values for the fields
    private double amount = 100000;
    private double rate = 7.5; // 7.5%
    private int numPeriods = 30;

    // Labels to identify the fields
    private JLabel amountLabel;
    private JLabel rateLabel;
    private JLabel numPeriodsLabel;
    private JLabel paymentLabel;

    // Fields for data entry
    private JFormattedTextField amountField;
    private JFormattedTextField rateField;
    private JFormattedTextField numPeriodsField;
    private JFormattedTextField paymentField;

    // Formats to format and parse numbers
    private static Currency currencyInstance;
    private NumberFormat amountFormat;
    private NumberFormat percentFormat;
    private NumberFormat paymentFormat;

    public InternationalizedMortgageCalculator(Locale currentLocale) {

        currencyInstance = Currency.getInstance(currentLocale);

        englishUSLocaleAction = new ChangeLocaleAction(
                "English, United States locale, en-US",
                "This is the English locale", new Integer(KeyEvent.VK_U),
                new Locale.Builder().setLanguage("en").setRegion("US")
                        .build());

        englishUKLocaleAction = new ChangeLocaleAction(
                "English, United Kingdom locale, en-UK",
                "This is the English locale", new Integer(KeyEvent.VK_G),
                new Locale.Builder().setLanguage("en").setRegion("GB")
                        .build());

        frenchFranceLocaleAction = new ChangeLocaleAction(
                "French, France locale, fr-FR",
                "This is the French locale", new Integer(KeyEvent.VK_F),
                new Locale.Builder().setLanguage("fr").setRegion("FR")
                        .build());

        frenchCanadaLocaleAction = new ChangeLocaleAction(
                "French, Canada locale, fr-CA",
                "This is the French locale", new Integer(KeyEvent.VK_C),
                new Locale.Builder().setLanguage("fr").setRegion("CA")
                        .build());

        arabicSaudiArabiaLocaleAction = new ChangeLocaleAction(
                "Arabic, Saudi Arabia locale, ar-SA",
                "This is the Arabic locale", new Integer(KeyEvent.VK_S),
                new Locale.Builder().setLanguage("ar").setRegion("SA")
                        .build());

        setUpFormats(currentLocale);

        double payment = computePayment(amount, rate, numPeriods);

        // Create the labels.

        labels = ResourceBundle.getBundle("resources.Resources",
                currentLocale);

        amountLabel = new JLabel(MessageFormat.format(
                labels.getString("AMOUNT_STRING"),
                currencyInstance.getDisplayName(currentLocale),
                currencyInstance.getSymbol(currentLocale)));

        rateLabel = new JLabel(labels.getString("RATE_STRING"));
        numPeriodsLabel = new JLabel(labels.getString("NUM_PERIODS_STRING"));
        paymentLabel = new JLabel(labels.getString("PAYMENT_STRING"));

        // Create the text fields and set them up.

        amountField = new JFormattedTextField(amountFormat);
        amountField.setValue(new Double(amount));
        amountField.setColumns(10);
        amountField.addPropertyChangeListener("value", this);

        rateField = new JFormattedTextField(percentFormat);
        rateField.setValue(new Double(rate));
        rateField.setColumns(10);
        rateField.addPropertyChangeListener("value", this);

        numPeriodsField = new JFormattedTextField();
        numPeriodsField.setValue(new Integer(numPeriods));
        numPeriodsField.setColumns(10);
        numPeriodsField.addPropertyChangeListener("value", this);

        paymentField = new JFormattedTextField(paymentFormat);
        paymentField.setValue(new Double(payment));
        paymentField.setColumns(10);
        paymentField.setEditable(false);
        paymentField.setForeground(Color.red);

        // Tell accessibility tools about label/textfield pairs.

        amountLabel.setLabelFor(amountField);
        rateLabel.setLabelFor(rateField);
        numPeriodsLabel.setLabelFor(numPeriodsField);
        paymentLabel.setLabelFor(paymentField);

        // Layout the labels and text fieds in a GridLayout

        JPanel labelsAndFieldsPane = new JPanel(new GridLayout(4, 2));
        labelsAndFieldsPane.add(amountLabel);
        labelsAndFieldsPane.add(amountField);
        labelsAndFieldsPane.add(rateLabel);
        labelsAndFieldsPane.add(rateField);
        labelsAndFieldsPane.add(numPeriodsLabel);
        labelsAndFieldsPane.add(numPeriodsField);
        labelsAndFieldsPane.add(paymentLabel);
        labelsAndFieldsPane.add(paymentField);
        setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
        add(labelsAndFieldsPane, BorderLayout.CENTER);
    }

    public JMenuBar createMenuBar() {
        JMenuItem menuItem = null;
        JMenuBar menuBar;

        // Create the menu bar.
        menuBar = new JMenuBar();

        // Create the first menu.
        JMenu mainMenu = new JMenu(labels.getString("LOCALE"));

        Action[] actions = { englishUSLocaleAction, englishUKLocaleAction,
                frenchFranceLocaleAction, frenchCanadaLocaleAction,
                arabicSaudiArabiaLocaleAction };

        for (int i = 0; i < actions.length; i++) {
            menuItem = new JMenuItem(actions[i]);
            menuItem.setIcon(null); // arbitrarily chose not to use icon
            mainMenu.add(menuItem);
        }

        // Set up the menu bar.
        menuBar.add(mainMenu);
        return menuBar;
    }

    public class ChangeLocaleAction extends AbstractAction {
        private String actionDesc;
        private Locale currentLocale;

        public ChangeLocaleAction(String textArg, String descArg,
                Integer mnemonicArg, Locale localeArg) {
            super(textArg);
            actionDesc = descArg;
            currentLocale = localeArg;
            putValue(SHORT_DESCRIPTION, descArg);
            putValue(MNEMONIC_KEY, mnemonicArg);
        }

        public void actionPerformed(ActionEvent e) {
            createAndShowGUI(currentLocale);
        }
    }

    /** Called when a field's "value" property changes. */
    public void propertyChange(PropertyChangeEvent e) {
        Object source = e.getSource();
        if (source == amountField) {
            amount = ((Number) amountField.getValue()).doubleValue();
        } else if (source == rateField) {
            rate = ((Number) rateField.getValue()).doubleValue();
        } else if (source == numPeriodsField) {
            numPeriods = ((Number) numPeriodsField.getValue()).intValue();
        }

        double payment = computePayment(amount, rate, numPeriods);
        paymentField.setValue(new Double(payment));
    }

    /**
     * Create the GUI and show it. For thread safety, this method should be
     * invoked from the event dispatch thread.
     */
    private static void createAndShowGUI(Locale currentLocale) {
        // Create and set up the window.

        InternationalizedMortgageCalculator demo = new InternationalizedMortgageCalculator(
                currentLocale);

        if (frame == null) {
            frame = new JFrame(labels.getString("WINDOW_TITLE"));
        } else {
            frame.getContentPane().removeAll();
            frame.setTitle(labels.getString("WINDOW_TITLE"));
        }

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // Add contents to the window.

        frame.add(demo);
        frame.setJMenuBar(demo.createMenuBar());
        frame.applyComponentOrientation(ComponentOrientation
                .getOrientation(currentLocale));

        // Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {

        // Schedule a job for the event dispatch thread:
        // creating and showing this application's GUI.
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                // Turn off metal's use of bold fonts
                Locale currentLocale = new Locale.Builder()
                        .setLanguage("en").setRegion("US").build();
                UIManager.put("swing.boldMetal", Boolean.FALSE);

                createAndShowGUI(currentLocale);
            }
        });
    }

    // Compute the monthly payment based on the loan amount,
    // APR, and length of loan.
    double computePayment(double loanAmt, double rate, int numPeriods) {
        double I, partial1, denominator, answer;

        numPeriods *= 12; // get number of months
        if (rate > 0.01) {
            I = rate / 100.0 / 12.0; // get monthly rate from annual
            partial1 = Math.pow((1 + I), (0.0 - numPeriods));
            denominator = (1 - partial1) / I;
        } else { // rate ~= 0
            denominator = numPeriods;
        }

        answer = (-1 * loanAmt) / denominator;
        return answer;
    }

    // Create and set up number formats. These objects also
    // parse numbers input by user.
    private void setUpFormats(Locale currentLocale) {
        amountFormat = NumberFormat.getNumberInstance();

        percentFormat = NumberFormat.getNumberInstance();
        percentFormat.setMinimumFractionDigits(3);

        paymentFormat = NumberFormat.getCurrencyInstance(currentLocale);
        paymentFormat.setCurrency(currencyInstance);
    }
}

• Previous
• Next

Related Tutorials

• Use setFormatterFactory() of JFormattedTextField to change the formatter
• JFormattedTextField can have four types of formatters
• Use JFormattedTextField to set a limit on the number of characters that can be entered in a field
• Create Calculator by Formatted Text Field
• Create formatted text field by FormatterFactory