implementing a class in class

Question

I am trying to implement a class in a class in JAVA, like this

package test;
import java.awt.event.*;
import javax.swing.*;
/**
 *
 * @author jackandjill
 */
public class Summingup extends JFrame {

    /**
     * Creates new form Summingup
     */
    public Summingup() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        input1_tb = new javax.swing.JTextField();
        calculate_btn = new javax.swing.JButton();
        result_lbl = new javax.swing.JLabel();
        input2_tb = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("Input 1");

        jLabel2.setText("Input 2");

        calculate_btn.setText("SUM");

        result_lbl.setText("RESULT DISPLAYED HERE!");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jLabel1)
                        .addGap(18, 18, 18)
                        .addComponent(input1_tb))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jLabel2)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGap(18, 18, 18)
                                .addComponent(result_lbl))
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGap(18, 18, 18)
                                .addComponent(input2_tb)))))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(calculate_btn)
                .addContainerGap())
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(1, 1, 1)
                        .addComponent(calculate_btn, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel1)
                            .addComponent(input1_tb, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel2)
                            .addComponent(input2_tb, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 20, Short.MAX_VALUE)
                .addComponent(result_lbl)
                .addContainerGap())
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Summingup.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new Summingup().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JButton calculate_btn;
    private javax.swing.JTextField input1_tb;
    private javax.swing.JTextField input2_tb;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JLabel result_lbl;
    // End of variables declaration
}

class InvalidValueException implements ActionListener
{
    public void actionPerformed(ActionEvent ae)
    {
         try
       {
           if(ae.getSource() ==calculate_btn)
           {
               String input_1 = input1_tb.getText();
                String input_2 = input2_tb.getText();

                checkBlanklnput(input_1,input_2);

                validateInput(Integer.parseInt(input_1),Integer.parseInt(input_2));

                result_lbl.setText(calculate(Integer.parseInt(input_1),Integer.parseInt(input_2)));

           }
       }

       catch (NumberFormatException excep)
       {
        result_lbl.setText("Invalid number");
       }
       catch (InvalidInputException excep)
       {
         result_lbl.setText(excep.getMessage());
       }
       catch (BlankInputException excep)
       {
         result_lbl.setText(excep.getMessage());
       }

    }



    public void checkBlanklnput(String input1,String input2) throws BlanklnputException 
    {
        if (input1.length() == 0 ||input2.length() == 0) throw new BlanklnputException();
    }

    public void validateInput(int input1 , int input2) throws InvalidInputException
    {

        if (input1 + input2 > 100 )
        throw new InvalidInputException();
    }

    public String calculate(int input1, int input2)
    {
        String res = "";
        while (true) 
        {
            res = Integer.toString(input1 + input2);
            break;
        }
        return res;

    }

}

class InvalidInputException extends Exception {

public InvalidInputException() {

super("Invalid number");

}
}
class BlankInputException extends Exception {

public BlankInputException() {

super("Input cannot be blank");

} 
 }

So this class is also throwing lot of exceptions and catching them. But the only problem is the JForm controls are not being recognised in the InvalidValueException class. Not sure how to open those controls to this class.

Another issue that I am facing is my validateInput is checking for maximum sum but I want to check for IF any alphabets other than numbers are entered in the textboxes.

This is what my GUI looks like

Answer 1

You might compare your implementation to the working example shown here. It uses JFormattedTextField to enforce numeric input, as well as a PropertyChangeListener & FocusListener to update the sum.

As an aside, you should study layouts before relying too much on a GUI editor. See also Nested Classes.

Addendum: BlankInputException was misspelled, and your (oddly named) ActionListener was unused. You should be able to initialize it using a custom code property.

calculate_btn.addActionListener(new InvalidValueException());