回想Java Beans[Java编程]

//: BangBean2.java
// You should write your Beans this way so they 
// can run in a multithreaded environment.
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;

public class BangBean2 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 Vector actionListeners = new Vector();
  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 paint(Graphics g) {
    g.setColor(Color.black);
    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) {
    actionListeners.addElement(l);
  }
  public synchronized void removeActionListener(
      ActionListener l) {
    actionListeners.removeElement(l);
  }
  // Notice this isn't synchronized:
  public void notifyListeners() {
    ActionEvent a =
      new ActionEvent(BangBean2.this,
        ActionEvent.ACTION_PERFORMED, null);
    Vector lv = null;
    // Make a copy of the vector in case someone
    // adds a listener while we're 
    // calling listeners:
    synchronized(this) {
      lv = (Vector)actionListeners.clone();
    }
    // Call all the listener methods:
    for(int i = 0; i < lv.size(); i++) {
      ActionListener al = 
        (ActionListener)lv.elementAt(i);
      al.actionPerformed(a);
    }
  }
  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();
      notifyListeners();
    }
  }
  class MM extends MouseMotionAdapter {
    public void mouseMoved(MouseEvent e) {
      xm = e.getX();
      ym = e.getY();
      repaint();
    }
  }
  // Testing the BangBean2:
  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");
      }
    });
    Frame aFrame = new Frame("BangBean2 Test");
    aFrame.addWindowListener(new WindowAdapter(){
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
    aFrame.add(bb, BorderLayout.CENTER);
    aFrame.setSize(300,300);
    aFrame.setVisible(true);
  }
} ///:~