Cylinder - Action Event Option 2

package actionEventOpt2;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;



/**
 *
 * @author zbawk
 */
public class CylinderFrame extends javax.swing.JFrame {

    /**
     * Creates new form CylinderFrame
     */
    public CylinderFrame() {
        initComponents();
        //Z.B: Second step
        //register Cylinder button with CylinderButtonListener to handle
        //this button click (action) event
       
        //1. Create an instance of CylinderButtonListener
        CylinderButtonListener cylinderListener = new CylinderButtonListener();
        //2. use addActionListener method to register the button
        jbtnCylinderPAV.addActionListener(cylinderListener);
       
        //you could do it in a single statement
       // jbtnCylinderPAV.addActionListener(new CylinderButtonListener());
       
        //ZB.Step 4;
        //register clear button with ClearListener
        jbtnClear.addActionListener(new ClearListener());
    }

   // Variables declaration - do not modify                    
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea jTextArea1;
    private javax.swing.JButton jbtnClear;
    private javax.swing.JButton jbtnCylinderPAV;
    private javax.swing.JTextField jtxtHeight;
    private javax.swing.JTextField jtxtRadius;
    // End of variables declaration                  

    //Z.B: define an inner class to listen for click (action) event of cylinder button
    //for this class to listen for action events it must implement the
    //ActionListener interface
   
    private class CylinderButtonListener implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent ae) {
            //throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
            //Code here runs when a button (associated or is registered with this class is clicked)
           
            //read data from user
            double r = Double.parseDouble(jtxtRadius.getText());
            double h = Double.parseDouble(jtxtHeight.getText());
            //compute
            double area = 2*Math.PI*r*h;
            double perimeter = 2*Math.PI*r;
            double volume = Math.PI*r*h;
           
            //display results
            //Create decimal format
            DecimalFormat df = new DecimalFormat("#.##");
           
            jTextArea1.setText("Perimeter = " + df.format(perimeter) + "\n" +
                    "area = " + df.format(area) + "\n" +
                    "volume = "+ df.format(volume));
                   
        }
       
    }
    //ZB: Step 3
    //an inner listener class for the clear button
    private class ClearListener implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent ae) {
            //the clear button will be associated with this class
            jtxtHeight.setText("");
            jtxtRadius.setText("");
            jTextArea1.setText("");
           
        }
       
    }

}//end of JFrame (this frame)