Drawing into a nested panel

Question

Hello,
I have an interface consisting of several panels nested together to accept user input on the left and output a shape on the right.
I have the user input widgets set up the way I want. I am about to add the listeners and handlers to each widget. However, before I do, I want to know how to draw the shape in the panel.
My code is below. I would like to accept the user input from the entry panel and output a shape (with code yet to be added) to the displayPanel.
Again, my question is, how do I draw anything into the displayPanel?
//import the necessary java packages
import java.awt.*;   //for the awt widgets
import javax.swing.*;  //for the swing widgets
import java.awt.event.*;  //for the event handler interfaces
public class DemoShape extends JApplet
    //declare private data members of the DemoShape class
    //required control buttons
    private JTextField xShapeText, yShapeText, messageText, fontSizeText;
    private ButtonGroup shapeRadio;
    private JRadioButton rect, oval, roundRect;
    private JComboBox shapeColorDrop, fontTypeDrop, fontColorDrop;
    //declare the entry and display panel containers
    private Container entire;
    private JPanel entryPanel, displayPanel;
    //create a text buffer to house the response messge
    String sText = "";
    //declare public data members of the DemoShape class
    //init method to initialize the applet objects
    public void init()
        //arrays of string to be used later in combo boxes
        //some are used more than once
        String fonts[] = {"Dialog", "Dialog Input", "Monospaced",
                            "Serif", "Sans Serif"};
        String shapes[] = {"Rectangle", "Round Rectangle", "Oval"};   
        String colors[] = {"Black", "Blue", "Cyan", "Dark Gray",
                            "Gray", "Green", "Light Gray", "Magenta", "Orange",
                            "Pink", "Red", "White", "Yellow"};
        //declare variables to assist with the layout
        //these are the left and right justified x coordinates
        int ljX = 10; int rjX = 150;
        //this is the y coordinates for the rows
        int yRow1 = 10;     //the shape
        int yRow2 = 40;
        int yRow3 = 60;
        int yRow4 = 130;
        int yRow5 = 150;
        int yRow6 = 210;    //the message
        int yRow7 = 240;
        int yRow8 = 260;
        int yRow9 = 300;
        int yRow10 = 320;
        int yRow11 = 360;
        int yRow12 = 380;
        //these are the widths for the text boxes, drop downs
        //message entry,  big message entry and radio buttons
        int tWidth = 30; int dWidth = 100;
        int mWidth = 125; int bmWidth = 250;
        int rWidth = 125;
        //the height is universal, even for the messages!
        int height = 25;
        //set a content pane for the entire applet
        //set the size of the entire window and show the entire applet
        entire = getContentPane();
        entire.setLayout(new GridLayout(1, 2));
        entire.setSize(800,600);
        //create the entry panel and add it to the entire pane
        entryPanel = new JPanel();
        entryPanel.setLayout(null);
        entire.add(entryPanel);
        //create the display panel and add it to the entire pane
        //this will display the output
        displayPanel = new JPanel();
        displayPanel.setLayout(null);
        entire.add(displayPanel);       
        //entry panel code
        //add the form elements in the form of rows
        //the first row (label)
        JLabel entryLabel = new JLabel("Enter Shape Parameters:");
        entryPanel.add(entryLabel);
        entryLabel.setBounds(ljX, yRow1, bmWidth, height);
        //second row (labels)
        JLabel shapeTypeLabel = new JLabel("Select Shape:");
        shapeTypeLabel.setBounds(ljX, yRow2, mWidth, height);
        entryPanel.add(shapeTypeLabel);
        JLabel shapeColorLabel = new JLabel("Select Shape Color:");
        shapeColorLabel.setBounds(rjX, yRow2, mWidth, height);
        entryPanel.add(shapeColorLabel);
        //third row (entry)        
        rect = new JRadioButton("Rectangle", true);
        oval = new JRadioButton("Oval", false);
        roundRect = new JRadioButton("Round Rectangle", false);
        rect.setBounds(ljX, yRow3, rWidth, height);
        oval.setBounds(ljX, yRow3 + 20, rWidth, height);
        roundRect.setBounds(ljX, yRow3 + 40, rWidth, height);
        shapeRadio = new ButtonGroup();
        shapeRadio.add(rect);
        shapeRadio.add(oval);
        shapeRadio.add(roundRect);
        entryPanel.add(rect);
        entryPanel.add(oval);
        entryPanel.add(roundRect);       
        shapeColorDrop = new JComboBox(colors);
        shapeColorDrop.setBounds(rjX, yRow3, dWidth, height);
        shapeColorDrop.addActionListener(new testListen());
        entryPanel.add(shapeColorDrop);
        //the fourth row (labels)
        JLabel xShapeLabel = new JLabel("Enter Width:");
        xShapeLabel.setBounds(ljX, yRow4, mWidth, height);
        entryPanel.add(xShapeLabel);
        JLabel yShapeLabel = new JLabel("Enter Height:");
        yShapeLabel.setBounds(rjX, yRow4, mWidth, height);
        entryPanel.add(yShapeLabel);
        //the fifth row (entry)
        xShapeText = new JTextField("200", 3);
        xShapeText.setBounds(ljX, yRow5, tWidth, height);
        entryPanel.add(xShapeText);        
        yShapeText = new JTextField("200", 3);
        yShapeText.setBounds(rjX, yRow5, tWidth, height);
        entryPanel.add(yShapeText);
        //the sixth row (label)
        JLabel messageLabel = new JLabel("Enter Message Parameters:");
        messageLabel.setBounds(ljX, yRow6, bmWidth, height);
        entryPanel.add(messageLabel);
        //the seventh row (labels)   
        JLabel messageEntryLabel= new JLabel("Enter Message:");
        messageEntryLabel.setBounds(ljX, yRow7, mWidth, height);
        entryPanel.add(messageEntryLabel);
        //the eighth row (entry)
        messageText = new JTextField(25);
        messageText.setBounds(ljX, yRow8, mWidth, height);
        entryPanel.add(messageText);
        //the ninth row (label)
        JLabel fontTypeLabel = new JLabel("Select Font:");
        fontTypeLabel.setBounds(ljX, yRow9, mWidth, height);
        entryPanel.add(fontTypeLabel);
        JLabel fontColorLabel = new JLabel("Select Font Color:");
        fontColorLabel.setBounds(rjX, yRow9, mWidth, height);
        entryPanel.add(fontColorLabel);
        //the tenth row (entry)
        fontTypeDrop = new JComboBox(fonts);
        fontTypeDrop.setBounds(ljX, yRow10, dWidth, height);
        entryPanel.add(fontTypeDrop);       
        fontColorDrop = new JComboBox(colors);
        fontColorDrop.setBounds(rjX, yRow10, dWidth, height);
        entryPanel.add(fontColorDrop);
        //the eleventh row (label)
        JLabel fontSizeLabel = new JLabel("Select Font Size:");
        fontSizeLabel.setBounds(ljX, yRow11, mWidth, height);
        entryPanel.add(fontSizeLabel);
        //the final row (entry)
        fontSizeText = new JTextField("12", 2);
        fontSizeText.setBounds(ljX, yRow12, tWidth, height);
        entryPanel.add(fontSizeText);
        //display panel code
        //simple test for the display panel
        JLabel test = new JLabel("Display Output Here");
        test.setBounds(10, 10, 150, 25);
        displayPanel.add(test);   
        //set the applet to visible
        entire.setSize(800, 600);
        entire.setVisible(true);
    }   //end the init method
    //declare an inner class to handle the events
    private class testListen implements ActionListener
        //supply the implementation of the actionPerformed method
        //pass an event variable as the argument
        public void actionPerformed(ActionEvent e)
            //get the source of the event
            if(e.getSource() == shapeColorDrop)
                sText = "shapeColorDrop pushed!";
                JOptionPane.showMessageDialog(null, sText);
        }   //end actionPeformed method
    }   //end testListen class
}   //end DemoShape class

Answer 1

Ok, I realize you need a canvas to draw into. Now how to I draw into this canvas.
//import the necessary java packages
import java.awt.*;   //for the awt widgets
import javax.swing.*;  //for the swing widgets
import java.awt.event.*;  //for the event handler interfaces
public class DemoShape extends JApplet
    //declare private data members of the DemoShape class
    //declare the entry and display panel containers
    private Container entire;       //houses the entryPanel and displayCanvas
    private JPanel entryPanel;      //accepts the user entries into widgets
    private Canvas displayCanvas;   //displays the response of the user entries
    //required control buttons for the entryPanel
    private JTextField xShapeText, yShapeText, messageText, fontSizeText;
    private ButtonGroup shapeRadio;
    private JRadioButton rect, oval, roundRect;
    private JComboBox shapeColorDrop, fontTypeDrop, fontColorDrop;
    //declare public data members of the DemoShape class
    //init method to initialize the applet objects
    public void init()
        //arrays of string to be used later in combo boxes
        //some are used more than once
        String fonts[] = {"Dialog", "Dialog Input", "Monospaced",
                            "Serif", "Sans Serif"};
        String shapes[] = {"Rectangle", "Round Rectangle", "Oval"};   
        String colors[] = {"Black", "Blue", "Cyan", "Dark Gray",
                            "Gray", "Green", "Light Gray", "Magenta", "Orange",
                            "Pink", "Red", "White", "Yellow"};
        //declare variables to assist with the layout
        //these are the left and right justified x coordinates
        int ljX = 10; int rjX = 150;
        //this is the y coordinates for the rows
        int yRow1 = 10;     //the shape rows
        int yRow2 = 40;
        int yRow3 = 60;
        int yRow4 = 130;
        int yRow5 = 150;
        int yRow6 = 210;    //the message rows
        int yRow7 = 240;
        int yRow8 = 260;
        int yRow9 = 300;
        int yRow10 = 320;
        int yRow11 = 360;
        int yRow12 = 380;
        //these are the widths for the text boxes, drop downs
        //message entry,  big message entry and radio buttons
        int tWidth = 30; int dWidth = 100;
        int mWidth = 125; int bmWidth = 250;
        int rWidth = 125;
        //the height is universal, even for the messages!
        int height = 25;
        //set a content pane for the entire applet
        //set the size of the entire window and show the entire applet
        entire = this.getContentPane();
        entire.setLayout(new GridLayout(1, 2));
        entire.setSize(800,600);
        //create the entry panel and add it to the entire pane
        entryPanel = new JPanel();
        entryPanel.setLayout(null);
        entire.add(entryPanel);
        //create the display canvas and add it to the entire pane
        //this will display the output
        displayCanvas = new Canvas();
        entire.add(displayCanvas);       
        //entry panel code
        //add the form elements in the form of rows
        //the first row (label)
        JLabel entryLabel = new JLabel("Enter Shape Parameters:");
        entryPanel.add(entryLabel);
        entryLabel.setBounds(ljX, yRow1, bmWidth, height);
        //second row (labels)
        JLabel shapeTypeLabel = new JLabel("Select Shape:");
        shapeTypeLabel.setBounds(ljX, yRow2, mWidth, height);
        entryPanel.add(shapeTypeLabel);
        JLabel shapeColorLabel = new JLabel("Select Shape Color:");
        shapeColorLabel.setBounds(rjX, yRow2, mWidth, height);
        entryPanel.add(shapeColorLabel);
        //third row (entry)        
        rect = new JRadioButton("Rectangle", true);
        oval = new JRadioButton("Oval", false);
        roundRect = new JRadioButton("Round Rectangle", false);
        rect.setBounds(ljX, yRow3, rWidth, height);
        oval.setBounds(ljX, yRow3 + 20, rWidth, height);
        roundRect.setBounds(ljX, yRow3 + 40, rWidth, height);
        shapeRadio = new ButtonGroup();
        shapeRadio.add(rect);
        shapeRadio.add(oval);
        shapeRadio.add(roundRect);
        entryPanel.add(rect);
        entryPanel.add(oval);
        entryPanel.add(roundRect);       
        shapeColorDrop = new JComboBox(colors);
        shapeColorDrop.setBounds(rjX, yRow3, dWidth, height);
        shapeColorDrop.addActionListener(new testListen());
        entryPanel.add(shapeColorDrop);
        //the fourth row (labels)
        JLabel xShapeLabel = new JLabel("Enter Width:");
        xShapeLabel.setBounds(ljX, yRow4, mWidth, height);
        entryPanel.add(xShapeLabel);
        JLabel yShapeLabel = new JLabel("Enter Height:");
        yShapeLabel.setBounds(rjX, yRow4, mWidth, height);
        entryPanel.add(yShapeLabel);
        //the fifth row (entry)
        xShapeText = new JTextField("200", 3);
        xShapeText.setBounds(ljX, yRow5, tWidth, height);
        entryPanel.add(xShapeText);        
        yShapeText = new JTextField("200", 3);
        yShapeText.setBounds(rjX, yRow5, tWidth, height);
        entryPanel.add(yShapeText);
        //the sixth row (label)
        JLabel messageLabel = new JLabel("Enter Message Parameters:");
        messageLabel.setBounds(ljX, yRow6, bmWidth, height);
        entryPanel.add(messageLabel);
        //the seventh row (labels)   
        JLabel messageEntryLabel= new JLabel("Enter Message:");
        messageEntryLabel.setBounds(ljX, yRow7, mWidth, height);
        entryPanel.add(messageEntryLabel);
        //the eighth row (entry)
        messageText = new JTextField(25);
        messageText.setBounds(ljX, yRow8, mWidth, height);
        entryPanel.add(messageText);
        //the ninth row (label)
        JLabel fontTypeLabel = new JLabel("Select Font:");
        fontTypeLabel.setBounds(ljX, yRow9, mWidth, height);
        entryPanel.add(fontTypeLabel);
        JLabel fontColorLabel = new JLabel("Select Font Color:");
        fontColorLabel.setBounds(rjX, yRow9, mWidth, height);
        entryPanel.add(fontColorLabel);
        //the tenth row (entry)
        fontTypeDrop = new JComboBox(fonts);
        fontTypeDrop.setBounds(ljX, yRow10, dWidth, height);
        entryPanel.add(fontTypeDrop);       
        fontColorDrop = new JComboBox(colors);
        fontColorDrop.setBounds(rjX, yRow10, dWidth, height);
        entryPanel.add(fontColorDrop);
        //the eleventh row (label)
        JLabel fontSizeLabel = new JLabel("Select Font Size:");
        fontSizeLabel.setBounds(ljX, yRow11, mWidth, height);
        entryPanel.add(fontSizeLabel);
        //the final row (entry)
        fontSizeText = new JTextField("12", 2);
        fontSizeText.setBounds(ljX, yRow12, tWidth, height);
        entryPanel.add(fontSizeText);
        //display panel code
        //set the applet to visible
        entire.setSize(800, 600);
        entire.setVisible(true);
    }   //end the init method
    //begin the paint method to the canvas
    public void paint(Graphics g)
        //how do I draw into the displayCanvas?????
    }   //end the paint method
}   //end DemoShape class