Write your Beans this way so they can run in a multithreaded environment : Swing Thread « Threads « Java

Write your Beans this way so they can run in a multithreaded environment

Write your Beans this way so they can run in a multithreaded environment
// : c14:BangBean2.java
// You should write your Beans this way so they
// can run in a multithreaded environment.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.io.Serializable;
import java.util.ArrayList;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class BangBean2 extends JPanel 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 ArrayList actionListeners = new ArrayList();

  public BangBean2() {
    addMouseListener(new ML());
    addMouseMotionListener(new MM());

  public synchronized int getCircleSize() {
    return cSize;

  public synchronized void setCircleSize(int newSize) {
    cSize = newSize;

  public synchronized String getBangText() {
    return text;

  public synchronized void setBangText(String newText) {
    text = newText;

  public synchronized int getFontSize() {
    return fontSize;

  public synchronized void setFontSize(int newSize) {
    fontSize = newSize;

  public synchronized Color getTextColor() {
    return tColor;

  public synchronized void setTextColor(Color newColor) {
    tColor = newColor;

  public void paintComponent(Graphics g) {
    g.drawOval(xm - cSize / 2, ym - cSize / 2, cSize, cSize);

  // This is a multicast listener, which is more typically
  // used than the unicast approach taken in BangBean.java:
  public synchronized void addActionListener(ActionListener l) {

  public synchronized void removeActionListener(ActionListener l) {

  // Notice this isn't synchronized:
  public void notifyListeners() {
    ActionEvent a = new ActionEvent(BangBean2.this,
        ActionEvent.ACTION_PERFORMED, null);
    ArrayList lv = null;
    // Make a shallow copy of the List in case
    // someone adds a listener while we're
    // calling listeners:
    synchronized (this) {
      lv = (ArrayList) actionListeners.clone();
    // Call all the listener methods:
    for (int i = 0; i < lv.size(); i++)
      ((ActionListener) lv.get(i)).actionPerformed(a);

  class ML extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
      Graphics g = getGraphics();
      g.setFont(new Font("TimesRoman", Font.BOLD, fontSize));
      int width = g.getFontMetrics().stringWidth(text);
      g.drawString(text, (getSize().width - width) / 2,
          getSize().height / 2);

  class MM extends MouseMotionAdapter {
    public void mouseMoved(MouseEvent e) {
      xm = e.getX();
      ym = e.getY();

  public static void main(String[] args) {
    BangBean2 bb = new BangBean2();
    bb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        System.out.println("ActionEvent" + e);
    bb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        System.out.println("BangBean2 action");
    bb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        System.out.println("More action");
    run(bb, 300, 300);

  public static void run(JPanel panel, int width, int height) {
    JFrame frame = new JFrame();
    frame.setSize(width, height);

} ///:~


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