/** 
 * This program is an example from the book "Internet 
 * programming with Java" by Svetlin Nakov. It is freeware. 
 * For more information: http://www.nakov.com/books/inetjava/ 
 */ 
import java.awt.*; 
import java.awt.event.*; 
import java.applet.*; 
 
public class SumatorApplet extends Applet { 
    private TextField mNumber1Field = new TextField(); 
    private TextField mNumber2Field = new TextField(); 
    private Button mCalcButton = new Button(); 
    private TextField mSumField = new TextField(); 
    private Color mLastBackgroundColor; 
 
    public void init() { 
        this.setBackground(Color.black); 
 
        // Set layout manager to null 
        this.setLayout(null); 
 
        // Create the first text field 
        mNumber1Field.setBounds(new Rectangle(20, 50, 60, 25)); 
        mNumber1Field.setBackground(Color.white); 
        this.add(mNumber1Field, null); 
 
        // Create the second text field 
        mNumber2Field.setBounds(new Rectangle(95, 50, 60, 25)); 
        mNumber2Field.setBackground(Color.white); 
        this.add(mNumber2Field, null); 
 
        // Create the "calculate sum" button 
        mCalcButton.setBounds(new Rectangle(170, 50, 90, 25)); 
        mCalcButton.addActionListener( 
            new ActionListener() { 
                public void actionPerformed(ActionEvent e) { 
                    calcSum(); 
                } 
            }); 
        mCalcButton.setLabel("calc sum"); 
        this.add(mCalcButton, null); 
 
        // Create the result text field 
        mSumField.setEditable(false); 
        mSumField.setBackground(Color.gray); 
        mSumField.setForeground(Color.white); 
        mSumField.setBounds(new Rectangle(20, 85, 240, 25)); 
        this.add(mSumField, null); 
    } 
 
    public boolean mouseDown(Event aEvent, int aX, int aY) { 
        mLastBackgroundColor = this.getBackground(); 
        this.setBackground(Color.red); 
        return true; 
    } 
 
    public boolean mouseUp(Event aEvent, int aX, int aY) { 
        this.setBackground(mLastBackgroundColor); 
        return true; 
    } 
 
    private void calcSum() { 
        try { 
            long s1 = new Long(mNumber1Field. 
                getText()).longValue(); 
            long s2 = new Long(mNumber2Field. 
                getText()).longValue(); 
            mSumField.setText(s1 + " + " + s2 + " = " + 
                (s1+s2)); 
        } catch (Exception ex) { 
            mSumField.setText("Error!"); 
        } 
    } 
 
    public void paint(Graphics aGraphics) { 
        super.paint(aGraphics); 
        Font font = new Font("Dialog", Font.BOLD, 23); 
        aGraphics.setFont(font); 
        aGraphics.setColor(Color.gray); 
        aGraphics.drawString("Test sumator applet", 20, 32); 
        aGraphics.setColor(Color.white); 
        aGraphics.drawString("Test sumator applet", 18, 30); 
    } 
 
    public static void main(String[] aArgs) { 
        Frame frame = new Frame("Sumator"); 
        frame.setSize(280,160); 
        SumatorApplet applet = new SumatorApplet(); 
        applet.init(); 
        frame.add(applet); 
        frame.setVisible(true); 
        applet.start(); 
    } 
}