Java Mortgage Calculator Reading a Sequential File [duplicate]

This question already has answers here: Closed 11 years ago.

Possible Duplicate:

How do I populate jcombobox from a textfile?

OK, I have an issue here that I cannot quiet figure out. I have a file that has variables on each line of: 5.35, 5.5, 5.75 in a file called apr.txt. I am reading the file and need to populate the file into a JComboBox. So far I have the file being read fine but cannot figure how to populate it into the JComboBox. This must be something easy. Can someone help point me in the proper direction?

Thank you for your help in advance.

import java.awt.*;
import java.text.NumberFormat;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.StringTokenizer;

import javax.swing.*;
import javax.swing.JComboBox;



  public class MortgageCalculatorGUI9 extends JFrame implements ActionListener
        {
         // Declarations

         //double [] Interest = {5.35, 5.5, 5.75};
         int [] Length = {7, 15, 30};
         double [] file_data = new double[3];


         JLabel mortgagelabel = new JLabel( "Principal Amount:$ " );
         JLabel paymentLabel = new JLabel( "Monthly Payment: " );
         JLabel intRateLabel = new JLabel( "Interest Rate %: " );
         JLabel termLabel = new JLabel( "Length of Loan of Loan in Years: "  );
         JTextField mortgagePrincipal = new JTextField(7);
         JTextField Payment = new JTextField(7);
         //JTextField intRateText = new JTextField(3);
         JComboBox intRateBox = new JComboBox();
         JTextField termText = new JTextField(3);
         JButton b7_535 = new JButton( "7 years at 5.35%" );
         JButton b15_55 = new JButton( "15 years at 5.50%" );
         JButton b30_575 = new JButton( "30 years at 5.75%");
         JButton exitButton = new JButton( "Exit" );
         JButton clearButton = new JButton( "Clear All" );
         JButton calculateButton = new JButton( "Calculate Loan" );
         JTextArea LoanPayments = new JTextArea(20,50);


        JScrollPane scroll = new JScrollPane(LoanPayments);

        public MortgageCalculatorGUI9()
        {
             //GUI setup
             super("Mortgage Calculator 1.0.5");
             setSize(800, 400);
             setLocation(500, 200);
             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
             JPanel pane = new JPanel(new GridLayout(3,1)); Container grid = getContentPane();
             grid.setLayout(new GridLayout(4,0,4,4)); pane.add(grid);
             pane.add(scroll);
             grid.add(mortgagelabel);
             grid.add(mortgagePrincipal);
             grid.add(intRateLabel);
             //grid.add(intRateText);
             grid.add (intRateBox);
             grid.add(termLabel);
             grid.add(termText);
             grid.add(paymentLabel);
             grid.add(Payment);
             grid.add(b7_535);
             grid.add(b15_55);
             grid.add(b30_575);
             grid.add(calculateButton);
             grid.add(clearButton);
             grid.add(exitButton);
             Payment.setEditable(false);
             setContentPane(pane);
             setContentPane(pane);
             setVisible(true);

            //add GUI functionality
            calculateButton.addActionListener (this);
            exitButton.addActionListener(this);
            clearButton.addActionListener(this);
            b7_535.addActionListener(this);
            b15_55.addActionListener(this);
            b30_575.addActionListener(this);
            mortgagePrincipal.addActionListener(this);
            //intRateText.addActionListener(this);
            intRateBox.addActionListener (this);
            termText.addActionListener(this);
            Payment.addActionListener(this);

         }

            public void actionPerformed(ActionEvent e)
                 {
                    Object command = e.getSource();

                    if (command == exitButton)
                 {

                    System.exit(0);

                 }
                 else if (command == b7_535)
                 {

                    calcLoan(Length[0], file_data[0]);

                 }
                 else if (command == b15_55)
                 {

                    calcLoan(Length[1], file_data[1]);

                 }
                 else if (command == b30_575)
                 {

                    calcLoan(Length[2], file_data[2]);

                 }

                 else if (command == calculateButton )
                 {

                    double terms = 0;
                    double rates = 0;
                    try

                 {
                     terms = Double.parseDouble(termText.getText());
                     //rates = Double.parseDouble(intRateText.getText());
                     read_File ();
                 }
                    catch (Exception ex)
                 {
                    LoanPayments.setText("Invalid term or rate Amount");
                    return;
                 }

                    calcLoan(terms, rates);

                 }

                 else if (command == clearButton)
                 {

                     mortgagePrincipal.setText("");
                     Payment.setText("");
                     //intRateText.setText("");
                     termText.setText("");
                     LoanPayments.setText("");

                 }

             }


             //Input File

                public void read_File()
                {

                    File inFile = new File("apr.txt");

                    try
                    {

                        BufferedReader istream = new BufferedReader(new FileReader(inFile));

                        for(int x=0;x<6;x++)
                        {
                            file_data[x]=Double.parseDouble (istream.readLine());
                        }



                    }

                    catch (Exception ex)
                        {

                            LoanPayments.setText ("Could Not Read From File.");
                            return;

                        }
                }



                //this is what needs to be done
                 private void calcLoan(double terms, double rates)

                 {

                     termText.setText(String.valueOf(terms) );
                     //intRateText.setText(String.valueOf(rates));
                     double amount = 0;

                 try
                 {

                    amount = Double.parseDouble(mortgagePrincipal.getText());

                 }

                    catch (Exception ex)

                 {

                    LoanPayments.setText("Invalid mortgage Amount");
                    return;

                 }

                     double interestRate = rates;

                     // Calculations
                     double intRate = (interestRate / 100) / 12;
                     int Months = (int)terms * 12;
                     double rate = (intRate / 12);
                     double payment = amount * intRate / (1 - (Math.pow(1/(1 +  intRate), Months)));
                     double remainingPrincipal = amount;
                     double MonthlyInterest = 0;
                     double MonthlyAmt = 0;
                     double[] balanceArray = new double[Months];
                     double[] interestArray = new double[Months];
                     double[] monthArray = new double[Months];
                     NumberFormat Money =  NumberFormat.getCurrencyInstance();
                     Payment.setText(Money.format(payment));
                     LoanPayments.setText("Month\tPrincipal\tInterest\tEnding  Balance\n");
                     int currentMonth = 0;

                        while(currentMonth < Months)
       开发者_StackOverflow                      {

                             //create loop calculations
                             MonthlyInterest = (remainingPrincipal * intRate);
                             MonthlyAmt = (payment - MonthlyInterest);
                             remainingPrincipal = (remainingPrincipal - MonthlyAmt);
                             LoanPayments.append((++currentMonth) + "\t" + Money.format(MonthlyAmt) + "\t" + Money.format(MonthlyInterest) + "\t" + Money.format(remainingPrincipal) + "\n");
                             balanceArray[currentMonth] = MonthlyAmt;
                             interestArray[currentMonth] = MonthlyInterest;
                             monthArray[currentMonth] = currentMonth;

                             }

                         }


            public static void main(String[] args)
             {

             MortgageCalculatorGUI9 frame= new MortgageCalculatorGUI9();

             }
 }

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Have you looked at the JComboBox API for a suitable method? If you start there, you'll likely get the right answer faster than asking in StackOverflow (hint it starts with "add... and ends with ...Item") ;)