Problems with JTable / JPanel

[mbutler755]

Hello all,

This is my first post on this forum and I am new to Java - so play nice. I am creating a project for school and I am stuck beyond belief. Our program is to create an amortization table using a GUI. We have done this project before without a GUI, so I just wanted to use what I already had and adapt it to a GUI. Since I am printing out an amortization table on the screen, I wanted to use JTable to make it nice and neat. However, I can't get the data[][] object to work right. Any help would be greatly appreciated.

    public static void amortizeLoan(double LoanBalance,double monthlyPayment,int numPayments,double interestRate){
        
        JFrame frame=new JFrame();
        frame.setSize(500,500);
        
        String[] columnNames={"Payment #","Loan Balance","Principal:","Interest Paid"};
        
        DecimalFormat money=new DecimalFormat("$0.00");           // Set the format for money
        double loanBalance=LoanBalance;                           // Copy the loan balance that is brought in
        double interestPaid=LoanBalance*interestRate/12;          // Set the interest paid
        double principalPaid=monthlyPayment-interestPaid;         // Set the principal paid
        for (int num=1;num<=numPayments;num++){                   // for loop to loop through all payments to find the balance, principal paid and interest paid

            // Print out the payment number, balance, principal paid and interest paid.
            System.out.print("#: "+num+"      Bal: "+money.format(loanBalance) +"      Principal: "+money.format(principalPaid) +"      Int: "+money.format(interestPaid)+"\n");
            Object[][] data={{num,money.format(loanBalance),money.format(principalPaid),money.format(interestPaid)}};
            // Decrement the values for the next payment
            loanBalance=loanBalance-principalPaid;
            interestPaid=loanBalance*interestRate/12;
            principalPaid=monthlyPayment-interestPaid;

            // Wait one quarter of a second between entries
            wait.quarterSec();
        }
        return;
        JTable table=new JTable(data,columnNames);
        
        JScrollPane scrollPane=new JScrollPane(table);
        table.setFillsViewportHeight(true);
        
        frame.add(scrollPane);
        frame.setVisible(true);
    }

This sub is called with three different loan values successively using an array. The monthlyPayments and interestRate are the only things that change. If you need more info, please let me know.

[Fubarable]

Hello and welcome to the forum. If your code generates any errors, you're best to post the actual error messages. Just looking at it, I'll bet that it doesn't compile as there's a return statement mid-method, and all the code below it is non-reachable. You might want to get rid of that. Also, I don't think that that wait.quarterSec() is going to do you any good here either. Also, you'll want to declare the data 2D object array before the for loop so that it is visible after the loop and so you don't erase previous values with each iteration of the loop but rather fill the already existing array with each iteration.

Best of luck and hope this helps.

[mbutler755]

Hello and welcome to the forum. If your code generates any errors, you're best to post the actual error messages. Just looking at it, I'll bet that it doesn't compile as there's a return statement mid-method, and all the code below it is non-reachable. You might want to get rid of that. Also, I don't think that that wait.quarterSec() is going to do you any good here either. Also, you'll want to declare the data 2D object array before the for loop so that it is visible after the loop and so you don't erase previous values with each iteration of the loop but rather fill the already existing array with each iteration.

Best of luck and hope this helps.

Actually, it compiles just fine. However, I get three windows showing only the first payment in each loan.

[Norm]

Have you tried to compile the code you posted? I get the following errors when I try:

TestCompile1.java:34: cannot find symbol
symbol : variable data
location: class TestCompile1
JTable table=new JTable(data,columnNames);
^
TestCompile1.java:40: unreachable statement

Can you find and post code that will compile?

[Fubarable]

Actually, it compiles just fine.

Then please post your real code. The code you've posted will not compile. Period.

However, I get three windows showing only the first payment in each loan.

Again, without your real code, we can't help you.

[mbutler755]

Then please post your real code. The code you've posted will not compile. Period.


Again, without your real code, we can't help you.

This is some altered code that I was working on. Unfortunately, this gives me too many windows because of the way that the method is called.

package wk3mbutler;

/**
 * Matt Butler
 * Week 3 - Individual Project
 */

// Imports for the program
import java.text.DecimalFormat;			// Import decimal format
import java.awt.event.ActionEvent;		// Import for ActionEvent
import java.awt.event.ActionListener;           // Import for ActionListener
import javax.swing.JFrame;			// Import for JFrame
import javax.swing.JPanel;			// Import for JPanel
import javax.swing.JTextField;			// Import for JTextField
import javax.swing.JButton;			// Import for JButton
import javax.swing.JLabel;			// Import for JLabel
import java.awt.GridLayout;                     // Import for the GridLayout
import java.awt.Container;                      // Import for the GridLayout Container
import javax.swing.JTable;
import java.awt.ScrollPane;
import javax.swing.JScrollPane;
import java.awt.BorderLayout;

// start of Main
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // Define what money should look like
        DecimalFormat money=new DecimalFormat("$0,000.00");

        // declare some variables for the program
        int totalMortgage=0;						// Total Mortgage amount
        int loanLengthInYears=0;					// Loan length in years
        int loanLengthInMonths=loanLengthInYears*12;			// Loan length in months = loan length in years / 12 months
        double annualInterestRate=0;					// Annual Interest Rate
        double monthlyInterestRate=(annualInterestRate/100)/12;		// Monthly interest rate = annual interest rate / 12 months

        // Setting up the window
        JFrame myWindow=new JFrame("Matt's Calculator");		// Setup a new frame and name it
        int windowWidth=400;						// define the window width
        int windowHeight=175;						// define the window height
        myWindow.setBounds(100,100, windowWidth, windowHeight);		// set the bounds of the window
        myWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	// set the 'x' to close & terminate the program when pushed
        myWindow.setVisible(true);					// set the window's visible property to true

        // Set up the panel
        JPanel myPanel=new JPanel();
        
        // Set up a grid layout
        GridLayout myLayout=new GridLayout(3,2,2,2);                    // Setup the grid layout
        Container content=myWindow.getContentPane();                    // Create a container and get the content pane
        content.setLayout(myLayout);                                    // Set the layout to the layout created
        
        // define the labels and text fields
        JLabel lblMortgageAmount=new JLabel(" Mortgage Amount: ",JLabel.RIGHT);     // Create a label for the mortgage amount
        final JTextField txtMortgageAmount=new JTextField(16);                      // Create a text field for the mortgage amount
        
        // Set up the Calculate button and a listener
        // for the button.
        JButton CalcButton=new JButton("Calculate Payment");		// Create a button to calculate the payments
        class calcLoanListener implements ActionListener{		// setup a listener for the calculate payment button
            public void actionPerformed(ActionEvent event){		// setup the event for the program to execute when the button is clicked

                int loanAmount=Integer.parseInt(txtMortgageAmount.getText());

                // Declare and initalize the arrays
                int[] loanYears=new int[3];
                double[] interestRate=new double[3];

                // Fill the arrays
                //   Loan 1: 07 years @ 5.35% interest
                //   Loan 2: 15 years @ 5.50% interest
                //   Loan 3: 30 years @ 5.75% interest
                loanYears[0]=7;
                loanYears[1]=15;
                loanYears[2]=30;
                interestRate[0]=5.35;
                interestRate[1]=5.5;
                interestRate[2]=5.75;

                // This is the while loop that iterates through the elements of the array
                // and then calls the method to calculate the loan information for the
                // specific elements in question.
                int count=0;
                while (count != loanYears.length) {
                    loanCalcs.calculateLoan(loanAmount, interestRate[count], loanYears[count]);
                    count++;
                } //end the while loop
            } // end actionPerformed
        } // end subclass calcLoanListener
        ActionListener myListener=new calcLoanListener();
        CalcButton.addActionListener(myListener);

        JButton clearButton=new JButton("Clear");
        class clearButtonListener implements ActionListener{
            public void actionPerformed(ActionEvent event){
                txtMortgageAmount.setText("");
            } // end actionPerformed
        } // end subclass clearButtonListener
        ActionListener clearButtonListener=new clearButtonListener();
        clearButton.addActionListener(clearButtonListener);

        // Add the items to the panel
        myWindow.add(lblMortgageAmount);	// add the lblMortgageAmount to the window
        myWindow.add(txtMortgageAmount);	// add the txtMortgageAmount to the window
        myWindow.add(CalcButton);		// add the calculate button to the window
        myWindow.add(clearButton);

        // Add the panel to the window
        myWindow.add(myPanel);

    } // end main
} // end class

//Start of class wait
class wait {

    // Gives me the ability to halt execution for one quarter of a second
    public static void quarterSec() {
        try {
            Thread.currentThread().sleep(250);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
     }

    // Gives me the ability to halt execution for one second
    public static void oneSec() {
        try {
            Thread.currentThread().sleep(1000);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    // Gives me the ability to halt the execution for a specified amount of time
    public static void manySec(long s) {
        try {
            Thread.currentThread().sleep(s * 1000);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
} //End class wait

// Start of loan calculations class
class loanCalcs {
    // Calculate the basic loan information
    public static void calculateLoan(int mortgageAmount,double interestRate,int yearsOfLoan){
        // Define what money should look like
        DecimalFormat money=new DecimalFormat("$0,000.00");

        // Create and set some variables for the program
        int totalMortgage=mortgageAmount;                     // Set the amount of the total mortgage
        int loanLengthInYears=yearsOfLoan;                    // Set the loan length the variable of the constructor
        int loanLengthInMonths=loanLengthInYears*12;          // Calculate the total number of monthly payments
        double annualInterestRate=interestRate/100;           // Set the annual interest rate 5.75% / 100 = .0575
        double monthlyInterestRate=annualInterestRate/12;     // Set the monthly interest rate (AnnualInterestRate / 12 months per year)
        double monthlyPayment=0.00;                           // Declare a variable for the monthly payment

        // Create the formula to get the monthly mortgage payment
        // with interest
	monthlyPayment=totalMortgage*(monthlyInterestRate/(1-Math.pow((1+monthlyInterestRate), -1*(loanLengthInMonths))));

        // Display the loan information to the user
        System.out.println();
        System.out.println(" Your total financed mortgage : "+money.format(totalMortgage));                         // Show the total amount financed
        System.out.println(" Your annual interest rate is : "+annualInterestRate*100 +"%");                         // Show the annual interest rate as a percentage
        System.out.println(" Total number of payments     : "+loanLengthInMonths);                                  // Total number of payments
        System.out.println(" Your monthly payment is      : "+money.format(monthlyPayment));                        // Show the monthly payment from the formula calculation
        System.out.println();
        loanCalcs.amortizeLoan(totalMortgage, monthlyPayment, loanLengthInMonths,annualInterestRate);

    } // end class loanCalcs

    // Amortizes the loan
    public static void amortizeLoan(double LoanBalance,double monthlyPayment,int numPayments,double interestRate){
        
        DecimalFormat money=new DecimalFormat("$0.00");           // Set the format for money
        double loanBalance=LoanBalance;                           // Copy the loan balance that is brought in
        double interestPaid=LoanBalance*interestRate/12;          // Set the interest paid
        double principalPaid=monthlyPayment-interestPaid;         // Set the principal paid
        for (int num=1;num<=numPayments;num++){                   // for loop to loop through all payments to find the balance, principal paid and interest paid

            // Print out the payment number, balance, principal paid and interest paid.
            System.out.print("#: "+num+"      Bal: "+money.format(loanBalance) +"      Principal: "+money.format(principalPaid) +"      Int: "+money.format(interestPaid)+"\n");
            loanCalcs.showOutput(num, loanBalance, principalPaid, interestPaid);
            // Decrement the values for the next payment
            loanBalance=loanBalance-principalPaid;
            interestPaid=loanBalance*interestRate/12;
            principalPaid=monthlyPayment-interestPaid;

            // Wait one quarter of a second between entries
            wait.quarterSec();
        }
        return;
    }

    public static void showOutput(int myPaymentNum,double myLoanBalance,double myPrincipalPaid, double myInterestPaid){

        String[] columnNames={"Payment #","Loan Balance","Principal:","Interest Paid"};
        int paymentNumber=myPaymentNum;
        double loanBalance=myLoanBalance;
        double principalPaid=myPrincipalPaid;
        double interestPaid=myInterestPaid;
        Object[][] data={{paymentNumber,loanBalance,principalPaid,interestPaid}};

        JFrame frame=new JFrame();
        frame.setSize(500,500);
        JTable table=new JTable(data,columnNames);
        JScrollPane scrollPane=new JScrollPane(table);
        table.setFillsViewportHeight(true);
        frame.add(scrollPane);
        frame.setVisible(true);
    }

    static void calculateLoan(String strMortAmount, String strIntRate, String strLoanLength) {
        throw new UnsupportedOperationException("Not yet implemented");
    }

    static void calculateLoan(int parseInt, String text, String text0) {
        throw new UnsupportedOperationException("Not yet implemented");
    }

    static void calculateLoan(int parseInt, double parseDouble, double parseDouble0) {
        throw new UnsupportedOperationException("Not yet implemented");
    }
} //End class amortize

[Norm]

this gives me too many windows

Can you explain why it gives you the second window
and then the next window
and then the next window???

You must have a reason for having more than one. What is it?
Without you describing what the program is supposed to do, no one can help you make the program do what you want.

[mbutler755]

Can you explain why it gives you the second window
and then the next window
and then the next window???

You must have a reason for having more than one. What is it?
Without you describing what the program is supposed to do, no one can help you make the program do what you want.

Exactly. This one gives you one window per line. Ideally, I would like to have three windows total. One window per loan. So, one loan would come out at 5.35% @ 84 months. The next would be 5.5% @ 180 months. The remaining loan would be 5.75% @ 360 months. I want all of the payments for the first loan to be in the first window, the second amount of payments in the second window and so on and so forth.

My apologies this was not clear. I was playing around with it between my OP and the full code post. The way it is now, is definately not going to work. If I can't get this to run the way that I want it to, I think I might just put it in a JTextArea. Ideally, I would like to have it in a JTable though.

[Norm]

You still have not answered my question about why the code keeps creating new windows.
How many windows do you want total?
What is supposed to go in each window?

Every time you call showOutput it opens a new window. Why?

[mbutler755]

You still have not answered my question about why the code keeps creating new windows.
How many windows do you want total?
What is supposed to go in each window?

Every time you call showOutput it opens a new window. Why?

Norm,

did you read my previous post? It says that I want three windows in total. It also says that I would want one window per loan.

[Norm]

You still miss answering the question about why you are opening so many windows.
Especially this question:
Every time you call showOutput it opens a new window. Why?

[mbutler755]

You still miss answering the question about why you are opening so many windows.
Especially this question:
Every time you call showOutput it opens a new window. Why?

Do you not know why? It's because every time showOutput is called it is creating a new window. I don't want this. I think I am going to have to put it in a JTextArea. The assignment is due tonight. I will just have to fix it.

[Norm]

because every time showOutput is called it is creating a new window. I don't want this.

Yes, you need to redesign the program to open the desired number of windows and use them to show what you want shown in each.

[mbutler755]

Yes, you need to redesign the program to open the desired number of windows and use them to show what you want shown in each.

Gee Norm. Any ideas on the best way to do this?

[Norm]

You want to have three windows. What do you want displayed in each window?
What classes and methods do you need to support displaying that data in each window?
Perhaps have a class for each window that takes care of opening, displaying and clearing the data.

[mbutler755]

Perhaps have a class for each window that takes care of opening, displaying and clearing the data.

Now that is an idea. I will code it and see how it pans out. Good job Norm!

[mbutler755]

Perhaps have a class for each window that takes care of opening, displaying and clearing the data.

This works perfectly Norm. Take a look and tell me what you think. Put in a loan value of 200000

package wk3mbutler;

/**
 * Matt Butler
 * Week 3 - Individual Project
 */

// Imports for the program
import java.text.DecimalFormat;			// Import decimal format
import java.awt.event.ActionEvent;		// Import for ActionEvent
import java.awt.event.ActionListener;           // Import for ActionListener
import javax.swing.JFrame;			// Import for JFrame
import javax.swing.JPanel;			// Import for JPanel
import javax.swing.JTextField;			// Import for JTextField
import javax.swing.JButton;			// Import for JButton
import javax.swing.JLabel;			// Import for JLabel
import java.awt.GridLayout;                     // Import for the GridLayout
import java.awt.Container;                      // Import for the GridLayout Container
import javax.swing.JScrollPane;                 // Import for JScrollPane
import javax.swing.JTextArea;                   // Import for JTextArea
import javax.swing.JOptionPane;                 // Import for JOptionPane

// start of Main
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // Define what money should look like
        DecimalFormat money=new DecimalFormat("$0,000.00");

        // declare some variables for the program
        int totalMortgage=0;						// Total Mortgage amount
        int loanLengthInYears=0;					// Loan length in years
        int loanLengthInMonths=loanLengthInYears*12;			// Loan length in months = loan length in years / 12 months
        double annualInterestRate=0;					// Annual Interest Rate
        double monthlyInterestRate=(annualInterestRate/100)/12;		// Monthly interest rate = annual interest rate / 12 months

        // Setting up the window
        JFrame myWindow=new JFrame("Matt's Calculator");		// Setup a new frame and name it
        int windowWidth=400;						// define the window width
        int windowHeight=175;						// define the window height
        myWindow.setBounds(100,100, windowWidth, windowHeight);		// set the bounds of the window
        myWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	// set the 'x' to close & terminate the program when pushed
        myWindow.setVisible(true);					// set the window's visible property to true

        // Set up the panel
        JPanel myPanel=new JPanel();
        
        // Set up a grid layout
        GridLayout myLayout=new GridLayout(3,2,2,2);                    // Setup the grid layout
        Container content=myWindow.getContentPane();                    // Create a container and get the content pane
        content.setLayout(myLayout);                                    // Set the layout to the layout created
        
        // define the labels and text fields
        JLabel lblMortgageAmount=new JLabel(" Mortgage Amount: ",JLabel.RIGHT);     // Create a label for the mortgage amount
        final JTextField txtMortgageAmount=new JTextField(16);                      // Create a text field for the mortgage amount
        
        // Set up the Calculate button and a listener
        // for the button.
        JButton CalcButton=new JButton("Calculate Payment");		// Create a button to calculate the payments
        class calcLoanListener implements ActionListener{		// setup a listener for the calculate payment button
            public void actionPerformed(ActionEvent event){		// setup the event for the program to execute when the button is clicked

                int loanAmount=Integer.parseInt(txtMortgageAmount.getText());

                // Declare and initalize the arrays
                int[] loanYears=new int[3];
                double[] interestRate=new double[3];

                // Fill the arrays
                //   Loan 1: 07 years @ 5.35% interest
                //   Loan 2: 15 years @ 5.50% interest
                //   Loan 3: 30 years @ 5.75% interest
                loanYears[0]=7;
                loanYears[1]=15;
                loanYears[2]=30;
                interestRate[0]=5.35;
                interestRate[1]=5.5;
                interestRate[2]=5.75;

                // This is the while loop that iterates through the elements of the array
                // and then calls the method to calculate the loan information for the
                // specific elements in question.
                int count=0;
                while (count != loanYears.length) {
                    guiLoans.showOutput(loanAmount, interestRate[count], loanYears[count]);
                    count++;
                } //end the while loop
            } // end actionPerformed
        } // end subclass calcLoanListener
        ActionListener myListener=new calcLoanListener();
        CalcButton.addActionListener(myListener);

        JButton clearButton=new JButton("Clear");
        class clearButtonListener implements ActionListener{
            public void actionPerformed(ActionEvent event){
                txtMortgageAmount.setText("");
            } // end actionPerformed
        } // end subclass clearButtonListener
        ActionListener clearButtonListener=new clearButtonListener();
        clearButton.addActionListener(clearButtonListener);

        // Add the items to the panel
        myWindow.add(lblMortgageAmount);	// add the lblMortgageAmount to the window
        myWindow.add(txtMortgageAmount);	// add the txtMortgageAmount to the window
        myWindow.add(CalcButton);		// add the calculate button to the window
        myWindow.add(clearButton);

        // Add the panel to the window
        myWindow.add(myPanel);

    } // end main
} // end class

//Start of class wait
class wait {

    // Gives me the ability to halt execution for one quarter of a second
    public static void quarterSec() {
        try {
            Thread.currentThread().sleep(250);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
     }

    // Gives me the ability to halt execution for one second
    public static void oneSec() {
        try {
            Thread.currentThread().sleep(1000);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    // Gives me the ability to halt the execution for a specified amount of time
    public static void manySec(long s) {
        try {
            Thread.currentThread().sleep(s * 1000);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
} //End class wait

// Start of loan calculations class
class loanCalcs {
    // Calculate the basic loan information
    public static void calculateLoan(int mortgageAmount,double interestRate,int yearsOfLoan){
        // Define what money should look like
        DecimalFormat money=new DecimalFormat("$0,000.00");

        // Create and set some variables for the program
        int totalMortgage=mortgageAmount;                     // Set the amount of the total mortgage
        int loanLengthInYears=yearsOfLoan;                    // Set the loan length the variable of the constructor
        int loanLengthInMonths=loanLengthInYears*12;          // Calculate the total number of monthly payments
        double annualInterestRate=interestRate/100;           // Set the annual interest rate 5.75% / 100 = .0575
        double monthlyInterestRate=annualInterestRate/12;     // Set the monthly interest rate (AnnualInterestRate / 12 months per year)
        double monthlyPayment=0.00;                           // Declare a variable for the monthly payment

        // Create the formula to get the monthly mortgage payment
        // with interest
	monthlyPayment=totalMortgage*(monthlyInterestRate/(1-Math.pow((1+monthlyInterestRate), -1*(loanLengthInMonths))));

        // Display the loan information to the user
        System.out.println();
        System.out.println(" Your total financed mortgage : "+money.format(totalMortgage));                         // Show the total amount financed
        System.out.println(" Your annual interest rate is : "+annualInterestRate*100 +"%");                         // Show the annual interest rate as a percentage
        System.out.println(" Total number of payments     : "+loanLengthInMonths);                                  // Total number of payments
        System.out.println(" Your monthly payment is      : "+money.format(monthlyPayment));                        // Show the monthly payment from the formula calculation
        System.out.println();
        loanCalcs.amortizeLoan(totalMortgage, monthlyPayment, loanLengthInMonths,annualInterestRate);

    } // end class loanCalcs

    // Amortizes the loan
    public static void amortizeLoan(double LoanBalance,double monthlyPayment,int numPayments,double interestRate){
        
        DecimalFormat money=new DecimalFormat("$0.00");           // Set the format for money
        double loanBalance=LoanBalance;                           // Copy the loan balance that is brought in
        double interestPaid=LoanBalance*interestRate/12;          // Set the interest paid
        double principalPaid=monthlyPayment-interestPaid;         // Set the principal paid
        for (int num=1;num<=numPayments;num++){                   // for loop to loop through all payments to find the balance, principal paid and interest paid

            // Print out the payment number, balance, principal paid and interest paid.
            System.out.print("#: "+num+"      Bal: "+money.format(loanBalance) +"      Principal: "+money.format(principalPaid) +"      Int: "+money.format(interestPaid)+"\n");

            // Decrement the values for the next payment
            loanBalance=loanBalance-principalPaid;
            interestPaid=loanBalance*interestRate/12;
            principalPaid=monthlyPayment-interestPaid;
            // Wait one quarter of a second between entries
            wait.quarterSec();
        } // end for loop
        return;
    } //end amortize loan calcs
} //End class amortize

class guiLoans{
    public static void showOutput(int mortgageAmount,double interestRate,int yearsOfLoan){

        DecimalFormat money=new DecimalFormat("$0,000.00");

        // Create and set some variables for the program
        int totalMortgage=mortgageAmount;                     // Set the amount of the total mortgage
        int loanLengthInYears=yearsOfLoan;                    // Set the loan length the variable of the constructor
        int loanLengthInMonths=loanLengthInYears*12;          // Calculate the total number of monthly payments
        double annualInterestRate=interestRate/100;           // Set the annual interest rate 5.75% / 100 = .0575
        double monthlyInterestRate=annualInterestRate/12;     // Set the monthly interest rate (AnnualInterestRate / 12 months per year)
        double monthlyPayment=0.00;                           // Declare a variable for the monthly payment

        // Create the formula to get the monthly mortgage payment
        // with interest
	monthlyPayment=totalMortgage*(monthlyInterestRate/(1-Math.pow((1+monthlyInterestRate), -1*(loanLengthInMonths))));

        // Create some JOptionPanes and display loan summaries before the amortization is displayed
        JOptionPane loanSummary=new JOptionPane();
        loanSummary.showMessageDialog(loanSummary, "For a "+money.format(mortgageAmount) +" with a " +interestRate +"% interest rate\nfor "+loanLengthInYears +" years, it would cost "+money.format(monthlyPayment)+" per month.");

        // Set up a frame and a scroll pane to add the results of the amortization
        JFrame frame=new JFrame();
        frame.setSize(500, 500);
        JScrollPane scrollPane=new JScrollPane();
        JTextArea resultsArea=new JTextArea();
        scrollPane.setViewportView(resultsArea);
        frame.add(scrollPane);
        frame.setVisible(true);
        frame.setTitle(money.format(totalMortgage)+" @ "+interestRate +"% for "+loanLengthInYears +" years");
        resultsArea.setEditable(false);

        DecimalFormat paymentMoney=new DecimalFormat("$0.00");    // Set the format for money
        int numPayments=yearsOfLoan*12;                           // get the numPayments by multiplying the loanLengthInYears by 12 months
        double loanBalance=totalMortgage;                         // Copy the loan balance that is brought in
        double interestPaid=loanBalance*(interestRate/100)/12;    // Set the interest paid
        double principalPaid=monthlyPayment-interestPaid;         // Set the principal paid
        for (int num=1;num<=numPayments;num++){                   // for loop to loop through all payments to find the balance, principal paid and interest paid

            // Print out the payment number, balance, principal paid and interest paid.
            resultsArea.append("#: "+num+"      Bal: "+paymentMoney.format(loanBalance) +"      Principal: "+paymentMoney.format(principalPaid) +"      Int: "+paymentMoney.format(interestPaid)+"\n");
            // Decrement the values for the next payment
            loanBalance=loanBalance-principalPaid;
            interestPaid=loanBalance*(interestRate/100)/12;
            principalPaid=monthlyPayment-interestPaid;
        } // end for loop
    } // end showOutput
} // end class guiLoans

[mbutler755]

While my previous post works great, I still have my heart set on using the JTable. I plugged in the following code, but I am having a problem with the data object since it is inside of the For loop. Any ideas on how I can fix this would be much appreciated.

class guiLoans{
    public static void showOutput(int mortgageAmount,double interestRate,int yearsOfLoan){

        DecimalFormat money=new DecimalFormat("$0,000.00");

        // Create and set some variables for the program
        int totalMortgage=mortgageAmount;                     // Set the amount of the total mortgage
        int loanLengthInYears=yearsOfLoan;                    // Set the loan length the variable of the constructor
        int loanLengthInMonths=loanLengthInYears*12;          // Calculate the total number of monthly payments
        double annualInterestRate=interestRate/100;           // Set the annual interest rate 5.75% / 100 = .0575
        double monthlyInterestRate=annualInterestRate/12;     // Set the monthly interest rate (AnnualInterestRate / 12 months per year)
        double monthlyPayment=0.00;                           // Declare a variable for the monthly payment

        // Create the formula to get the monthly mortgage payment
        // with interest
	monthlyPayment=totalMortgage*(monthlyInterestRate/(1-Math.pow((1+monthlyInterestRate), -1*(loanLengthInMonths))));

        // Create some JOptionPanes and display loan summaries before the amortization is displayed
        JOptionPane loanSummary=new JOptionPane();
        loanSummary.showMessageDialog(loanSummary, "For a "+money.format(mortgageAmount) +" with a " +interestRate +"% interest rate\nfor "+loanLengthInYears +" years, it would cost "+money.format(monthlyPayment)+" per month.");

        // Set up a frame and a scroll pane to add the results of the amortization
        JFrame frame=new JFrame();
        frame.setSize(500, 500);
        JScrollPane scrollPane=new JScrollPane();
        JTextArea resultsArea=new JTextArea();
        scrollPane.setViewportView(resultsArea);
        frame.add(scrollPane);
        frame.setVisible(true);
        frame.setTitle(money.format(totalMortgage)+" @ "+interestRate +"% for "+loanLengthInYears +" years");
        resultsArea.setEditable(false);

	JFrame testFrame=new JFrame();
	testFrame.setSize(600,600);
	JScrollPane testScrollPane=new JScrollPane();
	String[] columnNames={"Payment #","Balance","Principal","Interest"};

        DecimalFormat paymentMoney=new DecimalFormat("$0.00");    // Set the format for money
        int numPayments=yearsOfLoan*12;                           // get the numPayments by multiplying the loanLengthInYears by 12 months
        double loanBalance=totalMortgage;                         // Copy the loan balance that is brought in
        double interestPaid=loanBalance*(interestRate/100)/12;    // Set the interest paid
        double principalPaid=monthlyPayment-interestPaid;         // Set the principal paid
        for (int num=1;num<=numPayments;num++){                   // for loop to loop through all payments to find the balance, principal paid and interest paid

            // Print out the payment number, balance, principal paid and interest paid.
            resultsArea.append("#: "+num+"      Bal: "+paymentMoney.format(loanBalance) +"      Principal: "+paymentMoney.format(principalPaid) +"      Int: "+paymentMoney.format(interestPaid)+"\n");
            [B]Object[][] data={{num,paymentMoney.format(loanBalance),paymentMoney.format(principalPaid),paymentMoney.format(interestPaid)}};[/B]

            // Decrement the values for the next payment
            loanBalance=loanBalance-principalPaid;
            interestPaid=loanBalance*(interestRate/100)/12;
            principalPaid=monthlyPayment-interestPaid;
        } // end for loop
        JTable testTable=new JTable([B]data[/B], columnNames);
	testScrollPane.setViewportView(testTable);
	testFrame.add(testScrollPane);
	testFrame.setVisible(true);
    } // end showOutput

[Norm]

but I am having a problem with the data object

What is the problem?

If it is a scope problem, move the definition of the variable out of the {}s until it is at the same level as where you need it.

[mbutler755]

What is the problem?

If it is a scope problem, move the definition of the variable out of the {}s until it is at the same level as where you need it.

BOOYA!!

class guiLoans{
    public static void showOutput(int mortgageAmount,double interestRate,int yearsOfLoan){

        DecimalFormat money=new DecimalFormat("$0,000.00");

        // Create and set some variables for the program
        int totalMortgage=mortgageAmount;                     // Set the amount of the total mortgage
        int loanLengthInYears=yearsOfLoan;                    // Set the loan length the variable of the constructor
        int loanLengthInMonths=loanLengthInYears*12;          // Calculate the total number of monthly payments
        double annualInterestRate=interestRate/100;           // Set the annual interest rate 5.75% / 100 = .0575
        double monthlyInterestRate=annualInterestRate/12;     // Set the monthly interest rate (AnnualInterestRate / 12 months per year)
        double monthlyPayment=0.00;                           // Declare a variable for the monthly payment

        // Create the formula to get the monthly mortgage payment
        // with interest
	monthlyPayment=totalMortgage*(monthlyInterestRate/(1-Math.pow((1+monthlyInterestRate), -1*(loanLengthInMonths))));

        // Create some JOptionPanes and display loan summaries before the amortization is displayed
        JOptionPane loanSummary=new JOptionPane();
        loanSummary.showMessageDialog(loanSummary, "For a "+money.format(mortgageAmount) +" with a " +interestRate +"% interest rate\nfor "+loanLengthInYears +" years, it would cost "+money.format(monthlyPayment)+" per month.");

        // Set up a frame and a scroll pane to add the results of the amortization
        //JFrame frame=new JFrame();
        //frame.setSize(500, 500);
        //JScrollPane scrollPane=new JScrollPane();
        //JTextArea resultsArea=new JTextArea();
        //scrollPane.setViewportView(resultsArea);
        //frame.add(scrollPane);
        //frame.setVisible(true);
        //frame.setTitle(money.format(totalMortgage)+" @ "+interestRate +"% for "+loanLengthInYears +" years");
        //resultsArea.setEditable(false);

	JFrame testFrame=new JFrame();
	testFrame.setSize(600,600);
	JScrollPane testScrollPane=new JScrollPane();
	
	DefaultTableModel model=new DefaultTableModel();
        DecimalFormat paymentMoney=new DecimalFormat("$0.00");    // Set the format for money
        int numPayments=yearsOfLoan*12;                           // get the numPayments by multiplying the loanLengthInYears by 12 months
        double loanBalance=totalMortgage;                         // Copy the loan balance that is brought in
        double interestPaid=loanBalance*(interestRate/100)/12;    // Set the interest paid
        double principalPaid=monthlyPayment-interestPaid;         // Set the principal paid
        JTable testTable=new JTable(model);
        testScrollPane.setViewportView(testTable);
	testFrame.add(testScrollPane);
	testFrame.setVisible(true);
        testFrame.setTitle(money.format(totalMortgage)+" @ "+interestRate +"% for "+loanLengthInYears +" years = " +money.format(monthlyPayment) +"/mo");
        model.addColumn("Payment #");
        model.addColumn("Balance");
        model.addColumn("Principal");
        model.addColumn("Interest Paid");
        
        for (int num=1;num<=numPayments;num++){                   // for loop to loop through all payments to find the balance, principal paid and interest paid

            // Print out the payment number, balance, principal paid and interest paid.
            //resultsArea.append("#: "+num+"      Bal: "+paymentMoney.format(loanBalance) +"      Principal: "+paymentMoney.format(principalPaid) +"      Int: "+paymentMoney.format(interestPaid)+"\n");
            model.insertRow(num-1, new Object[]{num,paymentMoney.format(loanBalance),paymentMoney.format(principalPaid),paymentMoney.format(interestPaid)});
            // Decrement the values for the next payment
            loanBalance=loanBalance-principalPaid;
            interestPaid=loanBalance*(interestRate/100)/12;
            principalPaid=monthlyPayment-interestPaid;
        
        } // end for loop
    } // end showOutput