Java Alley | JavaBeans from Square One (Web Techniques, Sep 1997)

//: TestBangBean.java
// A graphical Bean
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;
class BangBean extends Canvas 
    implements Serializable {
  private int xm, ym;
  private int cSize = 20; // Circle size
  private String text = "Bang!";
  private int fontSize = 48;
  private Color tColor = Color.red;
  private ActionListener actionListener;
  public BangBean() {
    addMouseListener(new ML());
    addMouseMotionListener(new MM());
  }
  public int getCircleSize() { return cSize; }
  public void setCircleSize(int newSize) {
    cSize = newSize;
  }
  public String getBangText() { return text; }
  public void setBangText(String newText) {
    text = newText;
  }
  public int getFontSize() { return fontSize; }
  public void setFontSize(int newSize) {
    fontSize = newSize;
  }
  public Color getTextColor() { return tColor; }
  public void setTextColor(Color newColor) {
    tColor = newColor;
  }
  public void paint(Graphics g) {
    g.setColor(Color.black);
    g.drawOval(xm - cSize/2, ym - cSize/2, 
      cSize, cSize);
  }
  // This is a unicast listener, which is
  // the simplest form of listener management:
  public void addActionListener (
      ActionListener l) 
        throws TooManyListenersException {
    if(actionListener != null)
      throw new TooManyListenersException();
    actionListener = l;
  }
  public void removeActionListener(
      ActionListener l) {
    actionListener = null;
  }
  class ML extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
      Graphics g = getGraphics();
      g.setColor(tColor);
      g.setFont(
        new Font(
          "TimesRoman", Font.BOLD, fontSize));
      int width = 
        g.getFontMetrics().stringWidth(text);
      g.drawString(text, 
        (getSize().width - width) /2,
        getSize().height/2);
      g.dispose();
      // Call the listener's method:
      if(actionListener != null)
        actionListener.actionPerformed(
          new ActionEvent(BangBean.this,
            ActionEvent.ACTION_PERFORMED, null));
    }
  }
  class MM extends MouseMotionAdapter {
    public void mouseMoved(MouseEvent e) {
      xm = e.getX();
      ym = e.getY();
      repaint();
    }
  }
}
public class TestBangBean extends Frame {
  BangBean bb = new BangBean();
  public TestBangBean() \{
    setTitle("BangBean Test");
    addWindowListener(new WL());
    setSize(300,300);
    add(bb, BorderLayout.CENTER);
    try {
      bb.addActionListener(new BBL());
    } catch(TooManyListenersException e) {}
  }
  class WL extends WindowAdapter {
    public void windowClosing(WindowEvent e) {
      System.exit(0);
    }
  }
  class BBL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      System.out.println("BangBean action");
    }
  }
  public static void main(String args[]) {
    Frame f = new TestBangBean();
    f.setVisible(true);
  }
    }