Differences between awt and swing

Question

Ive written the following code, however Ive implemented the gui in awt rather then swing. Ive been told it hs too be in swing. What is the difference between swing and awt what will I need to change in my program so that its done using swing rather then the awt? Heres the code:
// pp.java
// Grant Brown
// 22/02/02
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
// =========================================================
// Class: pp
// This class drives the customer manager. It contains the
// main method which gets called as soon as this application
// begins to run.
// =========================================================
class pp extends Frame implements ActionListener
// Container of customer objects
private Vector customers = new Vector (100);
// List of names component. (Must specify java.awt in
// front of List to distinguish the List class in the
// java.awt package from the List class in the java.util
// package.)
private java.awt.List names = new java.awt.List ();
// Delete and update button components.
private Button delete;
private Button update;
// Default constructor.
public pp ()
// Assign "Paper Round Manager" to title bar of frame window.
super ("Paper Round Manager");
// Add a listener that responds to window closing
// events. When this event occurs (by clicking on the
// close box in the title bar), save customers and exit.
addWindowListener (new WindowAdapter ()
public void windowClosing
(WindowEvent e)
saveCustomers ();
System.exit (0);
// Place an empty label in the north part of the frame
// window. This is done to correct an AWT positioning
// problem.
Label l = new Label ();
add ("North", l);
// Place the names component in the center part of the
// frame window.
add ("Center", names);
// Create a panel object to hold four buttons.
Panel p = new Panel ();
Button b;
// Add an Insert button to the Panel object and register
// the current pp object as a listener for button events.
p.add (b = new Button ("Insert"));
b.addActionListener (this);
// Add a Delete button to the Panel object and register
// the current pp object as a listener for button events.
p.add (delete = new Button ("Delete"));
delete.addActionListener (this);
// The Delete button should be disabled until there is at
// least one customer to delete.
delete.setEnabled (false);
// Add an Update button to the Panel object and register
// the current pp object as a listener for button events.
p.add (update = new Button ("Update"));
update.addActionListener (this);
// The Update button should be disabled until there is at
// least one customer to update.
update.setEnabled (false);
// Add a Finish button to the Panel object and register
// the current customer object as a listener for button events.
p.add (b = new Button ("Finish"));
b.addActionListener (this);
// Add the panel object to the frame window container.
add ("South", p);
// Set the background of the frame window container to
// lightGray
setBackground (Color.lightGray);
// Set the size of the frame window container to 400
// pixels horizontally by 200 pixels vertically.
setSize (400, 200);
// Allow the user to resize the frame window.
setResizable (true);
// Load all contacts.
loadCustomers ();
// Make sure that the frame window is visible.
setVisible (true);
public void actionPerformed (ActionEvent e)
if (e.getActionCommand ().equals ("Delete"))
delete ();
else
if (e.getActionCommand ().equals ("Finish"))
saveCustomers ();
System.exit (0);
else
if (e.getActionCommand ().equals ("Insert"))
insert ();
else
update ();
public Insets getInsets ()
// Return an Insets object that describes the number of
// pixels to reserve as a border around the edges of the
// frame window.
return new Insets (10, 10, 10, 10);
public static void main (String [] args)
// Create a new pp object and let it do its thing.
new pp ();
private void delete ()
// Obtain index of selected contact item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a contact if no contact item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Remove the contact item from the names component.
names.remove (index);
// Remove the Customer object from the contacts Vector
// object.
customers.remove (index);
// If there are no more customers ...
if (customers.size () == 0)
delete.setEnabled (false);
update.setEnabled (false);
else
// Make sure that the first contact item in the names
// list is highlighted.
names.select (0);
private void insert ()
// Create an Insert data entry form to enter information
// for a new customer.
DataEntryForm def = new DataEntryForm (this, "Insert");
// If the bOk Boolean flag is set, this indicates the user
// exited the form by pressing the Ok button.
if (def.bOk)
// Create a Contact object and assign information from
// the form to its fields.
Customer temp = new Customer ();
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.round = new String (def.round.getText ());
temp.address = new String (def.address.getText ());
temp.phone = new String (def.phone.getText ());
// Add a new customer item to the names component.
names.add (temp.name + ", " + temp.publication);
// Add the Customer object to the contacts Vector
// object.
customers.add (temp);
// Make sure that the Delete and Update buttons are
// enabled.
delete.setEnabled (true);
update.setEnabled (true);
// Destroy the dialouge box.
def.dispose ();
// Make sure that the first customer item in the names list
// is highlighted.
names.select (0);
// ===========================================================
// Load all contacts from contacts.dat into the contacts
// Vector object. Also, make sure that the last name/first
// name from each contact is combined into a String object and
// inserted into the names component - as a contact item.
// ===========================================================
private void loadCustomers ()
FileInputStream fis = null;
try
fis = new FileInputStream ("Customers.dat");
DataInputStream dis = new DataInputStream (fis);
int nCustomers = dis.readInt ();
for (int i = 0; i < nCustomers; i++)
Customer temp = new Customer ();
temp.name = dis.readUTF ();
temp.publication = dis.readUTF ();
temp.round = dis.readUTF ();
temp.address = dis.readUTF ();
temp.phone = dis.readUTF ();
names.add (temp.name + ", " + temp.publication);
customers.add (temp);
if (nCustomers > 0)
delete.setEnabled (true);
update.setEnabled (true);
catch (IOException e)
finally
if (fis != null)
try
fis.close ();
catch (IOException e) {}
// Make sure that the first contact item in the names list
// is highlighted.
names.select (0);
// ========================================================
// Save all Customer objects from the customer Vector object
// to customer.dat. The number of customerss are saved as an
// int to make it easy for loadCustomers () to do its job.
// ========================================================
private void saveCustomers ()
FileOutputStream fos = null;
try
fos = new FileOutputStream ("customers.dat");
DataOutputStream dos = new DataOutputStream (fos);
dos.writeInt (customers.size ());
for (int i = 0; i < customers.size (); i++)
Customer temp = (Customer) customers.elementAt (i);
dos.writeUTF (temp.name);
dos.writeUTF (temp.publication);
dos.writeUTF (temp.round);
dos.writeUTF (temp.address);
dos.writeUTF (temp.phone);
catch (IOException e)
MsgBox mb = new MsgBox (this, "PP Error",
e.toString ());
mb.dispose ();
finally
if (fos != null)
try
fos.close ();
catch (IOException e) {}
private void update ()
// Obtain index of selected customer item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a customer if no customer item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Obtain a reference to the customer object (from the
// customers Vector object) that is associated with the
// index.
Customer temp = (Customer) customers.elementAt (index);
// Create and display an update entry form.
DataEntryForm def = new DataEntryForm (this, "Update",
temp.name,
temp.publication,
temp.round,
temp.address,
temp.phone);
// If the user pressed Ok...
if (def.bOk)
// Update the customer information in the customers
// Vector object.
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.round = new String (def.round.getText ());
temp.address = new String (def.address.getText ());
temp.phone = new String (def.phone.getText ());
// Make sure the screen reflects the update.
names.replaceItem (temp.name + ", " + temp.publication,
index);
// Destroy the dialouge box.
def.dispose ();
// Make sure that the first customer item in the names
// list is highlighted.
names.select (0);

Answer 1

Ive doen pretty much what you said burt now my program isnt working at all. The window comes up but instead of doing something when you click the button it just throws shit loads of exceptions. Heres my abridged code
// pp.java
// Grant Brown
// 22/02/02
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
// =========================================================
// Class:PP
// This class drives the Paper Round manager. It contains the
// main method which gets called as soon as this application
// begins to run.
// =========================================================
class pp extends JFrame implements ActionListener
// Container of customer objects (one object per customer)
private Vector customers = new Vector (100);
// List of names component. (Must specify java.awt in
// front of List to distinguish the List class in the
// java.awt package from the List class in the java.util
// package.)
private java.awt.List names = new java.awt.List ();
// Delete and update button components.
private JButton delete;
private JButton update;
// Default constructor.
public pp ()
// Assign Contact Manager to title bar of frame window.
super ("Paper Round Manager");
// Add a listener that responds to window closing
// events. When this event occurs (by clicking on the
// close box in the title bar), save contacts and exit.
addWindowListener (new WindowAdapter ()
public void windowClosing
(WindowEvent e)
saveCustomers ();
System.exit (0);
// Place an empty label in the north part of the frame
// window. This is done to correct an AWT positioning
// problem. (One thing that you'll come to realize as
// you work with the AWT is that there are lots of bugs.)
JLabel l = new JLabel ();
getContentPane().add ("North", l);
// Place the names component in the center part of the
// frame window.
getContentPane().add ("Center", names);
// Create a panel object to hold four buttons.
JPanel p = new JPanel ();
JButton b;
// Add an Insert button to the Panel object and register
// the current cm object as a listener for button events.
p.add (b = new JButton ("Insert"));
b.addActionListener (this);
// Add a Delete button to the Panel object and register
// the current cm object as a listener for button events.
p.add (delete = new JButton ("Delete"));
delete.addActionListener (this);
// The Delete button should be disabled until there is at
// least one contact to delete.
delete.setEnabled (false);
// Add an Update button to the Panel object and register
// the current cm object as a listener for button events.
p.add (update = new JButton ("Update"));
update.addActionListener (this);
// The Update button should be disabled until there is at
// least one contact to update.
update.setEnabled (false);
// Add a Finish button to the Panel object and register
// the current cm object as a listener for button events.
p.add (b = new JButton ("Finish"));
b.addActionListener (this);
// Add the panel object to the frame window container.
getContentPane().add ("South", p);
// Set the background of the frame window container to
// lightGray (to give a pleasing effect).
setBackground (Color.lightGray);
// Set the size of the frame window container to 400
// pixels horizontally by 200 pixels vertically.
setBounds (50, 100, 400, 200);
// Do not allow the user to resize the frame window.
loadCustomers ();
// Load all contacts.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Make sure that the frame window is visible.
setVisible (true);
public void actionPerformed (ActionEvent e)
if (e.getActionCommand ().equals ("Delete"))
delete ();
else
if (e.getActionCommand ().equals ("Finish"))
saveCustomers ();
System.exit (0);
else
if (e.getActionCommand ().equals ("Insert"))
insert ();
else
update ();
public Insets getInsets ()
// Return an Insets object that describes the number of
// pixels to reserve as a border around the edges of the
// frame window.
return new Insets (10, 10, 10, 10);
public static void main (String [] args)
// Create a new cm object and let it do its thing.
new pp ();
private void delete ()
// Obtain index of selected customer item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a contact if no contact item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Remove the customer item from the names component.
names.remove (index);
// Remove the Customer object from the contacts Vector
// object.
customers.remove (index);
// If there are no more customers ...
if (customers.size () == 0)
delete.setEnabled (false);
update.setEnabled (false);
else
// Make sure that the first contact item in the names
// list is highlighted.
names.select (0);
private void insert ()
// Create an Insert data entry form to enter information
// for a new contact.
DataEntryForm def = new DataEntryForm (this, "Insert");
// If the bOk Boolean flag is set, this indicates the user
// exited the form by pressing the Ok button.
if (def.bOk)
// Create a Customer object and assign information from
// the form to its fields.
Customer temp = new Customer ();
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.address = new String (def.address.getText ());
temp.round = new String (def.round.getText ());
temp.phone = new String
          (def.phone.getText ());
// Add a new customer item to the names component.
names.add (temp.publication + ", " + temp.address);
// Add the Customer object to the contacts Vector
// object.
customers.add (temp);
// Make sure that the Delete and Update buttons are
// enabled.
delete.setEnabled (true);
update.setEnabled (true);
// Destroy the dialog box.
def.dispose ();
// Make sure that the first customer item in the names list
// is highlighted.
names.select (0);
// ===========================================================
// Load all customers from customers.dat into the customers
// Vector object. Also, make sure that the last name/first
// name from each contact is combined into a String object and
// inserted into the names component - as a contact item.
// ===========================================================
private void loadCustomers ()
FileInputStream fis = null;
try
fis = new FileInputStream ("customers.dat");
DataInputStream dis = new DataInputStream (fis);
int nCustomers = dis.readInt ();
for (int i = 0; i < nCustomers; i++)
Customer temp = new Customer ();
temp.name = dis.readUTF ();
temp.publication = dis.readUTF ();
temp.address = dis.readUTF ();
temp.round = dis.readUTF ();
temp.phone = dis.readUTF ();
names.add (temp.publication + ", " + temp.address);
customers.add (temp);
if (nCustomers > 0)
delete.setEnabled (true);
update.setEnabled (true);
catch (IOException e)
finally
if (fis != null)
try
fis.close ();
catch (IOException e) {}
// Make sure that the first customer item in the names list
// is highlighted.
names.select (0);
// ========================================================
// Save all customer objects from the contacts Vector object
// to customers.dat. The number of contacts are saved as an
// int to make it easy for loadCustomers () to do its job.
// ========================================================
private void saveCustomers ()
FileOutputStream fos = null;
try
fos = new FileOutputStream ("customers.dat");
DataOutputStream dos = new DataOutputStream (fos);
dos.writeInt (customers.size ());
for (int i = 0; i < customers.size (); i++)
Customer temp = (Customer) customers.elementAt (i);
dos.writeUTF (temp.name);
dos.writeUTF (temp.publication);
dos.writeUTF (temp.address);
dos.writeUTF (temp.round);
dos.writeUTF (temp.phone);
catch (IOException e)
MsgBox mb = new MsgBox (this, "PP Error",
e.toString ());
mb.dispose ();
finally
if (fos != null)
try
fos.close ();
catch (IOException e) {}
private void update ()
// Obtain index of selected customer item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a customer if no customer item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Obtain a reference to the Customer object (from the
// customer Vector object) that is associated with the
// index.
Customer temp = (Customer) customers.elementAt (index);
// Create and display an update entry form.
DataEntryForm def = new DataEntryForm (this, "Update",
temp.name,
temp.publication,
temp.address,
temp.round,
temp.phone);
// If the user pressed Ok...
if (def.bOk)
// Update the customer information in the customers
// Vector object.
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.address = new String (def.address.getText ());
temp.round = new String (def.round.getText ());
temp.phone = new String (def.phone.getText ());
// Make sure the screen reflects the update.
names.replaceItem (temp.publication + ", " + temp.address,
index);
// Destroy the dialog box.
def.dispose ();
// Make sure that the first customer item in the names
// list is highlighted.
names.select (0);
// ========================================================
// Class: Customer
// This class describes the contents of a business customer.
// ========================================================
class Customer
public String name;
public String publication;
public String address;
public String round;
public String phone;
// ==========================================================
// Class: DataEntryForm
// This class provides a data entry form for entering customer
// information.
// ==========================================================
class DataEntryForm extends JDialog implements ActionListener
// bOk is a boolean flag. When true, it indicates that
// the Ok button was pressed to terminate the dialog box
// (as opposed to the Cancel button).
public boolean bOk;
// The following components hold the text that the user
// entered into the visible text fields.
public JTextField name;
public JTextField publication;
public JTextField address;
public JTextField round;
public JTextField phone;
public void actionPerformed (ActionEvent e)
// If the user pressed the Ok button, indicate this
// by assigning true to bOk.
if (e.getActionCommand ().equals ("Ok"))
bOk = true;
// Destroy the dialog box and return to the point
// just after the creation of the DataEntryForm object.
dispose ();
public DataEntryForm (JFrame parent, String title)
// Call the other constructor. The current constructor
// is used for insert operations. The other constructor
// is used for update operations.
this (parent, title, "", "", "", "", "");
public DataEntryForm (JFrame parent, String title,
String name, String publication,
String address, String round,
String phone)
// Initialize the superclass layer.
super (parent, title, true);
// Choose a grid bag layout so that components can be more
// accurately positioned. (It looks nicer.)
setLayout (new GridBagLayout ());
// Add appropriate first name, last name, phone, fax, and
// email components to the current DataEntryForm container.
// (Remember, DataEntryForm is a subclass of Dialog.
// Dialog is a container. Therefore, DataEntryForm
// inherits the ability to be a container.)
addComponent (this, new JLabel ("Name: "), 0, 0, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.name = new JTextField (15);
addComponent (this, this.name, 1, 0, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.name.setText (name);
addComponent (this, new JLabel ("Publications: "), 0, 1, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.publication = new JTextField (15);
addComponent (this, this.publication, 1, 1, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.publication.setText (publication);
addComponent (this, new JLabel ("Address "), 0, 2, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.address = new JTextField (15);
addComponent (this, this.address, 1, 2, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.address.setText (address);
addComponent (this, new JLabel ("Round No "), 0, 3, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.round = new JTextField (15);
addComponent (this, this.round, 1, 3, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.round.setText (round);
addComponent (this, new JLabel ("Phone Number "), 0, 4, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.phone = new JTextField (15);
addComponent (this, this.phone, 1, 4, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.phone.setText (phone);
addComponent (this, new JLabel (""), 0, 5, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
addComponent (this, new JLabel (""), 1, 5, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
JButton b;
// Add an Ok button to this container.
addComponent (this, b = new JButton ("Ok"), 0, 6, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
b.addActionListener (this);
// Add a Cancel button to this container.
addComponent (this, b = new JButton ("Cancel"), 1, 6, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
b.addActionListener (this);
// Set the size of the dialog window to 250 pixels
// horizontally by 200 pixels vertically.
setSize (250, 200);
// Do not allow users to resize the dialog window.
setResizable (false);
// Make sure that the dialog window is visible.
setVisible (true);
private void addComponent (Container con, Component com,
int gridx, int gridy,
int gridw, int gridh, int fill,
int anchor)
// Get the current layout manager. It is assumed to
// be a GridBagLayout object.
LayoutManager lm = con.getLayout ();
// Create a GridBagConstraints object to make it
// possible to customize component positioning.
GridBagConstraints gbc = new GridBagConstraints ();
// Assign the x and y grid positions.
gbc.gridx = gridx;
gbc.gridy = gridy;
// Assign the number of grid blocks horizontally and
// vertically that are occupied by the component.
gbc.gridwidth = gridw;
gbc.gridheight = gridh;
// Specify the component's resize policy (fill) and
// the direction in which the component is positioned
// when its size is smaller than available space (anchor).
gbc.fill = fill;
gbc.anchor = anchor;
// Set the new constraints that the grid bag layout
// manager will use.
((GridBagLayout) lm).setConstraints (com, gbc);
// Add the component to the container.
con.add (com);
// ===========================================================
// Class: MsgBox
// This class displays a message box to the user. The message
// is usually an error message. The user must press the Ok
// button to terminate the message box.
// ===========================================================
class MsgBox extends JDialog implements ActionListener
public void actionPerformed (ActionEvent e)
// Terminate the dialog box in response to the user
// pressing the Ok button.
dispose ();
public MsgBox (JFrame parent, String title, String msg)
// Initialize the superclass layer.
super (parent, title, true);
// Store the msg argument in a Label object and add
// this object to the center part of the dialog window.
JLabel l = new JLabel (msg);
add ("Center", l);
// Create a Button object and add it to the south part
// of the dialog window.
JButton b = new JButton ("Ok");
add ("South", b);
// Make the current object a listener to events that
// occur as a result of the user pressing the Ok
// button.
b.addActionListener (this);
// Make sure that the Ok button has the focus.
b.requestFocus ();
// Do not allow users to resize the dialog window.
setResizable (false);
// Allow the layout manager to choose an appropriate
// size for the dialog window.
pack ();
// Make sure that the dialog window is visible.
setVisible (true);
}