Browser.java Implementation of a simple browser in Swing. The user can specify a URL to load into the browser (JEditorPane). By attaching an Hyperlink Listener, the editor pane is responsive to hyperlinks selected by the user. Uses the following class and image:

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;

/** Very simplistic "Web browser" using Swing. Supply a URL on
 *  the command line to see it initially and to set the
 *  destination of the "home" button.
 *
  */

public class Browser extends JFrame implements HyperlinkListener, 
                                               ActionListener {
  public static void main(String[] args) {
    if (args.length == 0)
      new Browser("http://www.corewebprogramming.com/");
    else
      new Browser(args[0]);
  }

  private JIconButton homeButton;
  private JTextField urlField;
  private JEditorPane htmlPane;
  private String initialURL;

  public Browser(String initialURL) {
    super("Simple Swing Browser");
    this.initialURL = initialURL;
    addWindowListener(new ExitListener());
    WindowUtilities.setNativeLookAndFeel();

    JPanel topPanel = new JPanel();
    topPanel.setBackground(Color.lightGray);
    homeButton = new JIconButton("home.gif");
    homeButton.addActionListener(this);
    JLabel urlLabel = new JLabel("URL:");
    urlField = new JTextField(30);
    urlField.setText(initialURL);
    urlField.addActionListener(this);
    topPanel.add(homeButton);
    topPanel.add(urlLabel);
    topPanel.add(urlField);
    getContentPane().add(topPanel, BorderLayout.NORTH);

    try {
        htmlPane = new JEditorPane(initialURL);
        htmlPane.setEditable(false);
        htmlPane.addHyperlinkListener(this);
        JScrollPane scrollPane = new JScrollPane(htmlPane);
        getContentPane().add(scrollPane, BorderLayout.CENTER);
    } catch(IOException ioe) {
       warnUser("Can't build HTML pane for " + initialURL 
                + ": " + ioe);
    }

    Dimension screenSize = getToolkit().getScreenSize();
    int width = screenSize.width * 8 / 10;
    int height = screenSize.height * 8 / 10;
    setBounds(width/8, height/8, width, height);
    setVisible(true);
  }

  public void actionPerformed(ActionEvent event) {
    String url;
    if (event.getSource() == urlField) {
      url = urlField.getText();
    } else { // Clicked "home" button instead of entering URL.
      url = initialURL;
    }
    try {
      htmlPane.setPage(new URL(url));
      urlField.setText(url);
    } catch(IOException ioe) {
      warnUser("Can't follow link to " + url + ": " + ioe);
    }
  }

  public void hyperlinkUpdate(HyperlinkEvent event) {
    if (event.getEventType() == 
        HyperlinkEvent.EventType.ACTIVATED) {
      try {
        htmlPane.setPage(event.getURL());
        urlField.setText(event.getURL().toExternalForm());
      } catch(IOException ioe) {
        warnUser("Can't follow link to " 
                + event.getURL().toExternalForm() + ": " + ioe);
      }
    }
  }

  private void warnUser(String message) {
    JOptionPane.showMessageDialog(this, message, "Error", 
                                  JOptionPane.ERROR_MESSAGE);
  }
}

import java.awt.*;
import javax.swing.*;

/** Tiny example showing the main differences in using 
 *  JApplet instead of Applet: using the content pane,
 *  getting Java (Metal) look and feel by default, and
 *  having BorderLayout be the default instead of FlowLayout.
 *
  */
 
public class JAppletExample extends JApplet {
  public void init() {
    WindowUtilities.setNativeLookAndFeel();
    Container content = getContentPane();
    content.setBackground(Color.white);
    content.setLayout(new FlowLayout()); 
    content.add(new JButton("Button 1"));
    content.add(new JButton("Button 2"));
    content.add(new JButton("Button 3"));
  }
}

**************
ColorMenu.java 
**************
import java.awt.*;
import java.awt.event.*;

/** Illustrates the insertion of menu entries in Frame
 *  menu bars.
 *
 
public class ColorMenu extends CloseableFrame 
                       implements ActionListener {
                        
  private String[] colorNames =
    { "Black", "White", "Light Gray", "Medium Gray", 
      "Dark Gray" };
  private Color[] colorValues =
    { Color.black, Color.white, Color.lightGray, 
      Color.gray, Color.darkGray };
   
  public ColorMenu() {
    super("ColorMenu");
    MenuBar bar = new MenuBar();
    Menu colorMenu = new Menu("Colors");
    for(int i=0; i<2; i++) {
      colorMenu.add(colorNames[i]);
    }
    Menu grayMenu = new Menu("Gray");
    for(int i=2; i

# JTableSimpleExample.java Simple table that takes column names and data from arrays of Strings.

import java.awt.*;
import javax.swing.*;

/** Simple JTable example that uses a String array for the
 *  table header and table data.
 *
 */

public class JTableSimpleExample extends JFrame {
  public static void main(String[] args) {
    new JTableSimpleExample();
  }

  private final int COLUMNS = 4;
  private final int ROWS = 15;
  private JTable sampleJTable;

  public JTableSimpleExample() {
    super("Creating a Simple JTable");
    WindowUtilities.setNativeLookAndFeel();
    addWindowListener(new ExitListener());
    Container content = getContentPane();

    String[]   columnNames = buildColumnNames(COLUMNS);
    String[][] tableCells = buildTableCells(ROWS, COLUMNS);

    sampleJTable = new JTable(tableCells, columnNames);
    JScrollPane tablePane = new JScrollPane(sampleJTable);
    content.add(tablePane, BorderLayout.CENTER);
    setSize(450,150);
    setVisible(true);
  }

  private String[] buildColumnNames(int columns) {
    String[] header = new String[columns];
    for(int i=0; i

mport java.applet.Applet; import java.awt.*; 
*************************** 
/** Eight buttons: four each in two panels. * */ 
public class ButtonTest2 extends Applet { 
      public void init() { 
            String[] labelPrefixes = { 
            "Start", "Stop", "Pause", "Resume" 
            }; 
      Panel p1 = new Panel(); for (int i=0; i<4; i++) { 
            p1.add(new Button(labelPrefixes[i] + " Thread1")); 
      } 
      Panel p2 = new Panel(); for (int i=0; i<4; i++) { 
      p2.add(new Button(labelPrefixes[i] + " Thread2")); 
      } add(p1); add(p2); 
      } 
} 
**************************

All examples, except for FileTransfer use WindowUtilities.java and ExitListener.java.
WindowUtilities.java: 
import javax.swing.*;
import java.awt.*;   // For Color and Container classes.

/** A few utilities that simplify using windows in Swing. 
 *
  */

public class WindowUtilities {

  /** Tell system to use native look and feel, as in previous
   *  releases. Metal (Java) LAF is the default otherwise.
   */

  public static void setNativeLookAndFeel() {
    try {
     UIManager.setLookAndFeel(
       UIManager.getSystemLookAndFeelClassName());
    } catch(Exception e) {
      System.out.println("Error setting native LAF: " + e);
    }
  }

  public static void setJavaLookAndFeel() {
    try {
     UIManager.setLookAndFeel(
       UIManager.getCrossPlatformLookAndFeelClassName());
    } catch(Exception e) {
      System.out.println("Error setting Java LAF: " + e);
    }
  }

   public static void setMotifLookAndFeel() {
    try {
      UIManager.setLookAndFeel(
        "com.sun.java.swing.plaf.motif.MotifLookAndFeel");
    } catch(Exception e) {
      System.out.println("Error setting Motif LAF: " + e);
    }
  }

  /** A simplified way to see a JPanel or other Container. Pops
   *  up a JFrame with specified Container as the content pane.
   */

  public static JFrame openInJFrame(Container content,
                                    int width,
                                    int height,
                                    String title,
                                    Color bgColor) {
    JFrame frame = new JFrame(title);
    frame.setBackground(bgColor);
    content.setBackground(bgColor);
    frame.setSize(width, height);
    frame.setContentPane(content);
    frame.addWindowListener(new ExitListener());
    frame.setVisible(true);
    return(frame);
  }

  /** Uses Color.white as the background color. */

  public static JFrame openInJFrame(Container content,
                                    int width,
                                    int height,
                                    String title) {
    return(openInJFrame(content, width, height,
                        title, Color.white));
  }

  /** Uses Color.white as the background color, and the
   *  name of the Container's class as the JFrame title.
   */

  public static JFrame openInJFrame(Container content,
                                    int width,
                                    int height) {
    return(openInJFrame(content, width, height,
                        content.getClass().getName(),
                        Color.white));
  }
}
**//
ExitListener.java.:
import java.awt.*;
import java.awt.event.*;

/** A listener that you attach to the top-level JFrame of
 *  your application, so that quitting the frame exits the 
 *  application.
 *
  */
public class ExitListener extends WindowAdapter {
  public void windowClosing(WindowEvent event) {
    System.exit(0);
  }
}
**//

JList Examples

* JListSimpleExample.java Illustrates creating a simple list. In this example, all the entries for the list are stored in a String array and later supplied in the JList constructor. In addition, a private class, ValueReporter, implements a ListSelectionListener to display the last entry in the list selected by the user.

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;

/** Simple JList example illustrating
 *  


     *    
    Creating a JList, which we do by passing values 
     *        directly to the JList constructor, rather than 
     *        using a ListModel, and
     *    
    Attaching a listener to determine when values change.
     *  


 */

public class JListSimpleExample extends JFrame {
  public static void main(String[] args) {
    new JListSimpleExample();
  }

  private JList sampleJList;
  private JTextField valueField;
  
  public JListSimpleExample() {
    super("Creating a Simple JList");
    WindowUtilities.setNativeLookAndFeel();
    addWindowListener(new ExitListener());
    Container content = getContentPane();

    // Create the JList, set the number of visible rows, add a
    // listener, and put it in a JScrollPane.
    String[] entries = { "Entry 1", "Entry 2", "Entry 3",
                         "Entry 4", "Entry 5", "Entry 6" };
    sampleJList = new JList(entries);
    sampleJList.setVisibleRowCount(4);
    sampleJList.addListSelectionListener(new ValueReporter());
    JScrollPane listPane = new JScrollPane(sampleJList);
    Font displayFont = new Font("Serif", Font.BOLD, 18);
    sampleJList.setFont(displayFont);

    JPanel listPanel = new JPanel();
    listPanel.setBackground(Color.white);
    Border listPanelBorder =
      BorderFactory.createTitledBorder("Sample JList");
    listPanel.setBorder(listPanelBorder);
    listPanel.add(listPane);
    content.add(listPanel, BorderLayout.CENTER);
    JLabel valueLabel = new JLabel("Last Selection:");
    valueLabel.setFont(displayFont);
    valueField = new JTextField("None", 7);
    valueField.setFont(displayFont);
    valueField.setEditable(false);
    JPanel valuePanel = new JPanel();
    valuePanel.setBackground(Color.white);
    Border valuePanelBorder =
      BorderFactory.createTitledBorder("JList Selection");
    valuePanel.setBorder(valuePanelBorder);
    valuePanel.add(valueLabel);
    valuePanel.add(valueField);
    content.add(valuePanel, BorderLayout.SOUTH);
    pack();
    setVisible(true);
  }

  private class ValueReporter implements ListSelectionListener {

    /** You get three events in many cases -- one for the 
     *  deselection of the originally selected entry, one 
     *  indicating the selection is moving, and one for the 
     *  selection of the new entry. In the first two cases, 
     *  getValueIsAdjusting returns true; thus, the test below
     *  when only the third case is of interest.
     */

    public void valueChanged(ListSelectionEvent event) {
      if (!event.getValueIsAdjusting()) {
        Object value = sampleJList.getSelectedValue();
        if (value != null) {
          valueField.setText(value.toString());
        }  
      }
    }
  }
}
**//

DefaultListModelExample.java Creates a list using a DefaultListModel. By default, a JList doesn’t permit you to directly add new entries; however, with the DefaultListModel you can add or delete entries to the model (which are reflected in the list).

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

/** JList example illustrating
 *  


     *    
    The creation of a JList by creating a DefaultListModel,
     *        adding the values there, then passing that to the
     *        JList constructor.
     *    
    Adding new values at runtime, the key thing that 
     *        DefaultListModel lets you do that you can't do with
     *        a JList where you supply values directly.
     *  


 *
 */

public class DefaultListModelExample extends JFrame {
  public static void main(String[] args) {
    new DefaultListModelExample();
  }

  JList sampleJList;
  private DefaultListModel sampleModel;
  
  public DefaultListModelExample() {
    super("Creating a Simple JList");
    WindowUtilities.setNativeLookAndFeel();
    addWindowListener(new ExitListener());
    Container content = getContentPane();
   
    String[] entries = { "Entry 1", "Entry 2", "Entry 3",
                         "Entry 4", "Entry 5", "Entry 6" };
    sampleModel = new DefaultListModel();
    for(int i=0; ibefore trying to scroll
     *  to make the index visible.
     */

    public void actionPerformed(ActionEvent event) {
      int index = sampleModel.getSize();
      sampleModel.addElement("Entry " + (index+1));
      ((JComponent)getContentPane()).revalidate();
      sampleJList.setSelectedIndex(index);
      sampleJList.ensureIndexIsVisible(index);
    }
  }
}
**//

# JListCustomModel.java  Example illustrating that you can use your own custom data model (data structure) to hold the entries in a list. Uses the following classes:

* JavaLocationListModel.java A custom list model (implements ListModel interface which provides support for custom data structures) to store data for the list.
* JavaLocationCollection.java A simple collection of JavaLocation (below) objects.
* JavaLocation.java An object representing a city named Java. Defines the country where the Java city is located, along with a comment and country flag (gif image).

JListCustomModel.java:
import java.awt.*;
import javax.swing.*;

/** Simple JList example illustrating the use of a custom
 *  ListModel (JavaLocationListModel).
 *
  */

public class JListCustomModel extends JFrame {
  public static void main(String[] args) {
    new JListCustomModel();
  }

  public JListCustomModel() {
    super("JList with a Custom Data Model");
    WindowUtilities.setNativeLookAndFeel();
    addWindowListener(new ExitListener());
    Container content = getContentPane();

    JavaLocationCollection collection =
      new JavaLocationCollection();
    JavaLocationListModel listModel =
      new JavaLocationListModel(collection);
    JList sampleJList = new JList(listModel);
    Font displayFont = new Font("Serif", Font.BOLD, 18);
    sampleJList.setFont(displayFont);
    content.add(sampleJList);

    pack();
    setVisible(true);
  }
}
**//
# JavaLocationListModel.java:

import javax.swing.*;
import javax.swing.event.*;

/** A simple illustration of writing your own ListModel.
 *  Note that if you wanted the user to be able to add and
 *  remove data elements at runtime, you should start with
 *  AbstractListModel and handle the event reporting part.
 *
 */

public class JavaLocationListModel implements ListModel {
  private JavaLocationCollection collection;
  
  public JavaLocationListModel(JavaLocationCollection collection) {
    this.collection = collection;
  }

  public Object getElementAt(int index) {
    return(collection.getLocations()[index]);
  }

  public int getSize() {
    return(collection.getLocations().length);
  }

  public void addListDataListener(ListDataListener l) {}

  public void removeListDataListener(ListDataListener l) {}
}

**//

JavaLocationCollection.java:
/** A simple collection that stores multiple JavaLocation
 *  objects in an array and determines the number of
 *  unique countries represented in the data.
 *
 */

public class JavaLocationCollection {
  private static JavaLocation[] defaultLocations =
    { new JavaLocation("Belgium",
                       "near Liege",
                       "flags/belgium.gif"),
      new JavaLocation("Brazil",
                       "near Salvador",
                       "flags/brazil.gif"),
      new JavaLocation("Colombia",
                       "near Bogota",
                       "flags/colombia.gif"),
      new JavaLocation("Indonesia",
                       "main island",
                       "flags/indonesia.gif"),
      new JavaLocation("Jamaica",
                       "near Spanish Town",
                       "flags/jamaica.gif"),
      new JavaLocation("Mozambique",
                       "near Sofala",
                       "flags/mozambique.gif"),
      new JavaLocation("Philippines",
                       "near Quezon City",
                       "flags/philippines.gif"),
      new JavaLocation("Sao Tome",
                       "near Santa Cruz",
                       "flags/saotome.gif"),
      new JavaLocation("Spain",
                       "near Viana de Bolo",
                       "flags/spain.gif"),
      new JavaLocation("Suriname",
                       "near Paramibo",
                       "flags/suriname.gif"),
      new JavaLocation("United States",
                       "near Montgomery, Alabama",
                       "flags/usa.gif"),
      new JavaLocation("United States",
                       "near Needles, California",
                       "flags/usa.gif"),
      new JavaLocation("United States",
                       "near Dallas, Texas",
                       "flags/usa.gif")
    };

  private JavaLocation[] locations;
  private int numCountries;

  public JavaLocationCollection(JavaLocation[] locations) {
    this.locations = locations;
    this.numCountries = countCountries(locations);
  }
  
  public JavaLocationCollection() {
    this(defaultLocations);
  }

  public JavaLocation[] getLocations() {
    return(locations);
  }

  public int getNumCountries() {
    return(numCountries);
  }

  // Count the number of unique countries in the data.
  // Assumes the list is sorted by country name
  private int countCountries(JavaLocation[] locations) {
    int n = 0;
    String currentCountry, previousCountry = "None";
    for(int i=0;i
 *  Note that this method can get called lots and lots of times
 *  as you click on entries. We don't want to keep generating 
 *  new ImageIcon objects, so we make a Hashtable that associates 
 *  previously displayed values with icons, reusing icons for 
 *  entries that have been displayed already.
 *  


 *  Note that in the first release of JDK 1.2, the default 
 *  renderer  has a bug: the renderer doesn't clear out icons for 
 *  later entries. So if you mix plain strings and ImageIcons in 
 *  your JList, the plain strings still get an icon. The 
 *  call below clears the old icon when the value is not a 
 *  JavaLocation.
 *
 
 */

public class JavaLocationRenderer extends 
                                  DefaultListCellRenderer {
  private Hashtable iconTable = new Hashtable();
  
  public Component getListCellRendererComponent(JList list,
                                                Object value,
                                                int index,
                                                boolean isSelected,
                                                boolean hasFocus) {
    // First build the label containing the text, then 
    // later add the image.
    JLabel label =
      (JLabel)super.getListCellRendererComponent(list,
                                                 value,
                                                 index,
                                                 isSelected,
                                                 hasFocus);
    if (value instanceof JavaLocation) {
      JavaLocation location = (JavaLocation)value;
      ImageIcon icon = (ImageIcon)iconTable.get(value);
      if (icon == null) {
        icon = new ImageIcon(location.getFlagFile());
        iconTable.put(value, icon);
      }
      label.setIcon(icon);
    } else {
      // Clear old icon; needed in 1st release of JDK 1.2.
      label.setIcon(null); 
    }
    return(label);
  }
}
**//
# JavaLocationListModel.java A custom list model (implements ListModel interface) to store data for a list.
# JavaLocationCollection.java A simple collection of JavaLocation (below) objects.
# JavaLocation.java An object representing a city named Java. Defines the country where the Java 
city is located, along with a comment and country flag

import java.awt.*;
import java.applet.Applet;

/** Position circles down the diagonal so that their borders
 *  just touch. Illustrates that AWT components are 
 *  rectangular and opaque.
  */

public class CircleTest2 extends Applet {
  public void init() {
    setBackground(Color.lightGray);
    setLayout(null); // Turn off layout manager.
    Circle circle;
    int radius = getSize().width/6;
    int deltaX = round(2.0 * (double)radius / Math.sqrt(2.0));
    for (int x=radius; x<6*radius; x=x+deltaX) {
      circle = new Circle(Color.black, radius);
      add(circle);
      circle.setCenter(x, x);
    }
  }

  private int round(double num) {
    return((int)Math.round(num));
  }
}
*********************************
Circle.java
*********************************
import java.awt.*;

/** A Circle component built using a Canvas. 
 *
  */

public class Circle extends Canvas {
  private int width, height;        
        
  public Circle(Color foreground, int radius) {
    setForeground(foreground);
    width = 2*radius;
    height = 2*radius;
    setSize(width, height);
  }

  public void paint(Graphics g) {
    g.fillOval(0, 0, width, height);
  }

  public void setCenter(int x, int y) {
    setLocation(x - width/2, y - height/2);
  }
}
*****************************

import java.awt.*;
import java.applet.Applet;

/** Insert three circles into an Applet using FlowLayout. 
 *
 */

public class CircleTest extends Applet {
  public void init() {
    setBackground(Color.lightGray);
    add(new Circle(Color.white, 30));
    add(new Circle(Color.gray, 40));
    add(new Circle(Color.black, 50));
  }
}

*********************************************
Test2.java Accesses methods in a Ship2 object
*********************************************

// Give the ship public move and printLocation methods.

class Ship2 {
  public double x=0.0, y=0.0, speed=1.0, direction=0.0;
  public String name = "UnnamedShip";

  private double degreesToRadians(double degrees) {
    return(degrees * Math.PI / 180.0);
  }

  public void move() {
    double angle = degreesToRadians(direction);
    x = x + speed * Math.cos(angle);
    y = y + speed * Math.sin(angle);
  }

  public void printLocation() {
    System.out.println(name + " is at " +
                       "(" + x + "," + y + ").");
  }
}

public class Test2 {
  public static void main(String[] args) {
    Ship2 s1 = new Ship2();
    s1.name = "Ship1";
    Ship2 s2 = new Ship2();
    s2.direction = 135.0; // Northwest
    s2.speed = 2.0;
    s2.name = "Ship2";
    s1.move();
    s2.move();
    s1.printLocation();
    s2.printLocation();
  }
}
**********************