Question

Add appropriate descriptive comments to each line of code in the project explaining why the code is in the application.

public class FutureValueFrame extends JFrame {

private JTextField investmentField;
private JTextField interestRateField;
private JComboBox yearsComboBox;
private JList futureValueList;
private DefaultListModel futureValueModel;

public FutureValueFrame() {
initComponents();
}

private void initComponents() {
try {
UIManager.setLookAndFeel(
UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException |
IllegalAccessException | UnsupportedLookAndFeelException e) {
System.out.println(e);
}

setTitle("Future Value Calculator");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationByPlatform(true);

investmentField = new JTextField();
interestRateField = new JTextField();
yearsComboBox = new JComboBox();
futureValueList = new JList();
futureValueModel = new DefaultListModel<>();
JScrollPane futureValuePane = new JScrollPane(futureValueList);
  
Dimension dim = new Dimension(150, 20);
investmentField.setPreferredSize(dim);
investmentField.setMinimumSize(dim);
interestRateField.setPreferredSize(dim);
interestRateField.setMinimumSize(dim);
yearsComboBox.setPreferredSize(dim);
yearsComboBox.setMinimumSize(dim);

Dimension dim2 = new Dimension(150, 80);
futureValuePane.setPreferredSize(dim2);
futureValuePane.setMinimumSize(dim2);

JButton calculateButton = new JButton("Calculate");
JButton exitButton = new JButton("Exit");

calculateButton.addActionListener(e -> calculateButtonClicked());
exitButton.addActionListener(e -> exitButtonClicked());

// button panel
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
buttonPanel.add(calculateButton);
buttonPanel.add(exitButton);
  
for (int i = 1; i < 21; i++) {
yearsComboBox.addItem(i);
}
yearsComboBox.setSelectedIndex(2);

// main panel
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
panel.add(new JLabel("Monthly Investment:"), getConstraints(0, 0));
panel.add(investmentField, getConstraints(1, 0));
panel.add(new JLabel("Yearly Interest Rate:"), getConstraints(0, 1));
panel.add(interestRateField, getConstraints(1, 1));
panel.add(new JLabel("Years:"), getConstraints(0, 2));
panel.add(yearsComboBox, getConstraints(1, 2));
panel.add(new JLabel("Future Value:"), getConstraints(0, 3));
panel.add(futureValuePane, getConstraints(1, 3));

add(panel, BorderLayout.CENTER);
add(buttonPanel, BorderLayout.SOUTH);
  
pack();
setVisible(true);
}

// helper method for getting a GridBagConstraints object
private GridBagConstraints getConstraints(int x, int y) {
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.LINE_START;
c.insets = new Insets(5, 5, 0, 5);
c.gridx = x;
c.gridy = y;
return c;
}

private void calculateButtonClicked() {
double investment = Double.parseDouble(investmentField.getText());
double interestRate = Double.parseDouble(interestRateField.getText());
int years = (int) yearsComboBox.getSelectedItem();

NumberFormat currency = NumberFormat.getCurrencyInstance();
futureValueModel.clear();
double futureValue;
String yearlyString;
for (int year = 1; year <= years; year++) {
futureValue = FinancialCalculations.calculateFutureValue(
investment, interestRate, year);
yearlyString = "Year " + year + ": " +
currency.format(futureValue);
futureValueModel.addElement(yearlyString);
}
futureValueList.setModel(futureValueModel);
}

private void exitButtonClicked() {
System.exit(0);
}
  
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(() -> {
JFrame frame = new FutureValueFrame();
});
}
}

Answer 1

/***************************************FutureValueFrame.java*******************************/

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.text.NumberFormat;

import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

/**
*
* @author Insert Your Name Here
*
*/
public class FutureValueFrame extends JFrame {

   /*
   * TextField for investment and
   * TextField for interestRate
   * By using TextField type variable
   * year ComboBox which is drop down list
   * list contain
   */
   private JTextField investmentField;
   private JTextField interestRateField;
   private JComboBox yearsComboBox;
   private JList futureValueList;
   private DefaultListModel futureValueModel;

   public FutureValueFrame() {
       initComponents();
   }

   private void initComponents() {
       /*
       * try catch block to encounter the exception
       */
       try {
           UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
       } catch (ClassNotFoundException | InstantiationException | IllegalAccessException
               | UnsupportedLookAndFeelException e) {
           System.out.println(e);
       }

       /*
       * set the title of the application
       */
       setTitle("Future Value Calculator");
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       setLocationByPlatform(true);

       /*
       * creating text fields
       */
       investmentField = new JTextField();
       interestRateField = new JTextField();
       yearsComboBox = new JComboBox();
       futureValueList = new JList();
       futureValueModel = new DefaultListModel<>();
       /*
       * JScrollPane creates a scroll pane
       */
       JScrollPane futureValuePane = new JScrollPane(futureValueList);

       /*
       * Dimension will create a new object with specified height and width
       */
       Dimension dim = new Dimension(150, 20);
       /*
       * Set all field and combo box size
       */
       investmentField.setPreferredSize(dim);
       investmentField.setMinimumSize(dim);
       interestRateField.setPreferredSize(dim);
       interestRateField.setMinimumSize(dim);
       yearsComboBox.setPreferredSize(dim);
       yearsComboBox.setMinimumSize(dim);

       /*
       * set futureValuePane size
       */
       Dimension dim2 = new Dimension(150, 80);
       futureValuePane.setPreferredSize(dim2);
       futureValuePane.setMinimumSize(dim2);

       /*
       * Create two buttons by JButton class
       */
       JButton calculateButton = new JButton("Calculate");
       JButton exitButton = new JButton("Exit");

       /*
       * Apply the ActionListener to the buttons
       */
       calculateButton.addActionListener(e -> calculateButtonClicked());
       exitButton.addActionListener(e -> exitButtonClicked());

       // button panel
       JPanel buttonPanel = new JPanel();
       /*
       * Create the button panel
       * and add button to the buttonPanel
       */
       buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
       buttonPanel.add(calculateButton);
       buttonPanel.add(exitButton);

       for (int i = 1; i < 21; i++) {
           yearsComboBox.addItem(i);
       }
       yearsComboBox.setSelectedIndex(2);

       // main panel
       JPanel panel = new JPanel();
       /*
       * set the GridBagLayout
       * add labels and text field to GridBagLayout in the panel
       */
       panel.setLayout(new GridBagLayout());
       panel.add(new JLabel("Monthly Investment:"), getConstraints(0, 0));
       panel.add(investmentField, getConstraints(1, 0));
       panel.add(new JLabel("Yearly Interest Rate:"), getConstraints(0, 1));
       panel.add(interestRateField, getConstraints(1, 1));
       panel.add(new JLabel("Years:"), getConstraints(0, 2));
       panel.add(yearsComboBox, getConstraints(1, 2));
       panel.add(new JLabel("Future Value:"), getConstraints(0, 3));
       panel.add(futureValuePane, getConstraints(1, 3));

       //adjust the panel to center
       add(panel, BorderLayout.CENTER);
       //adjust the button panel to bottom
       add(buttonPanel, BorderLayout.SOUTH);

       pack();
       setVisible(true);
   }

   // helper method for getting a GridBagConstraints object
   private GridBagConstraints getConstraints(int x, int y) {
       /*
       * GridBagConstraints specifies how to display a specific component.
       * Every component added to a GridBagLayout container should have a GridBagConstraints object associated with it.
       */
       GridBagConstraints c = new GridBagConstraints();
       c.anchor = GridBagConstraints.LINE_START;
       c.insets = new Insets(5, 5, 0, 5);
       c.gridx = x;
       c.gridy = y;
       return c;
   }

   private void calculateButtonClicked() {
       /*
       * get the value from the text field in the variables
       * investment and interestRate
       * get the years from the combo box
       */
       double investment = Double.parseDouble(investmentField.getText());
       double interestRate = Double.parseDouble(interestRateField.getText());
       int years = (int) yearsComboBox.getSelectedItem();

       /*
       * The NumberFormat class used to format the currency according to Locale
       */
       NumberFormat currency = NumberFormat.getCurrencyInstance();
       futureValueModel.clear();
       double futureValue;
       String yearlyString;
       /*
       * add element in the futureValueModel
       * year wise
       */
       for (int year = 1; year <= years; year++) {
           /*
           * calculate the future value by calling static method calculateFutureValue of
           * FinancialCalculations Class
           */
           futureValue = FinancialCalculations.calculateFutureValue(investment, interestRate, year);
           /*
           * set the yearString year with currency
           */
           yearlyString = "Year " + year + ": " + currency.format(futureValue);
           //add the yearString to the futureValueModel
           futureValueModel.addElement(yearlyString);
       }
      
       futureValueList.setModel(futureValueModel);
   }

   /*
   * Exit the Application when clicked on exit button
   */
   private void exitButtonClicked() {
       System.exit(0);
   }

   /*
   * Start the application
   */
   public static void main(String args[]) {
       java.awt.EventQueue.invokeLater(() -> {
           JFrame frame = new FutureValueFrame();
       });
   }
}

Thanks a lot, Please let me know if you have any problem...........