//: DynamicEvents.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source.
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
// suffered by you or any third party as a result of
// using or distributing software. In no event will
// Bruce Eckel or the publisher be liable for any
// lost revenue, profit, or data, or for direct,
// indirect, special, consequential, incidental, or
// punitive damages, however caused and regardless of
// the theory of liability, arising out of the use of
// or inability to use software, even if Bruce Eckel
// and the publisher have been advised of the
// possibility of such damages. Should the software
// prove defective, you assume the cost of all
// necessary servicing, repair, or correction. If you
// think you've found an error, please email all
// modified files with clearly commented changes to:
// Bruce@EckelObjects.com. (Please use the same
// address for non-code errors found in the book.)
/////////////////////////////////////////////////
// The new Java 1.1 event model allows you to
// change event behavior dynamically. Also
// demonstrates multiple actions for an event.
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class DynamicEvents extends Frame {
Vector v = new Vector();
int i = 0;
Button
b1 = new Button("Button 1"),
b2 = new Button("Button 2");
public DynamicEvents() {
setLayout(new FlowLayout());
b1.addActionListener(new B());
b1.addActionListener(new B1());
b2.addActionListener(new B());
b2.addActionListener(new B2());
add(b1);
add(b2);
}
class B implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.out.println("A button was pressed");
}
}
class CountListener implements ActionListener {
int index;
public CountListener(int i) { index = i; }
public void actionPerformed(ActionEvent e) {
System.out.println(
"Counted Listener " + index);
}
}
class B1 implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.out.println("Button 1 pressed");
ActionListener a = new CountListener(i++);
v.addElement(a);
b2.addActionListener(a);
}
}
class B2 implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.out.println("Button 2 pressed");
int end = v.size() -1;
if(end >= 0) {
b2.removeActionListener(
(ActionListener)v.elementAt(end));
v.removeElementAt(end);
}
}
}
public static void main(String[] args) {
Frame f = new DynamicEvents();
f.addWindowListener(
new WindowAdapter() {
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
f.setSize(300,200);
f.show();
}
} ///:~ |