Uses reflection to create groups of different types of AbstractButton
// : c14:ButtonGroups.java
// Uses reflection to create groups
// of different types of AbstractButton.
// <applet code=ButtonGroups width=500 height=300></applet>
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import java.awt.Container;
import java.awt.FlowLayout;
import java.lang.reflect.Constructor;
import javax.swing.AbstractButton;
import javax.swing.ButtonGroup;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JToggleButton;
import javax.swing.border.TitledBorder;
public class ButtonGroups extends JApplet {
private static String[] ids = { "June", "Ward", "Beaver", "Wally", "Eddie",
"Lumpy", };
static JPanel makeBPanel(Class klass, String[] ids) {
ButtonGroup bg = new ButtonGroup();
JPanel jp = new JPanel();
String title = klass.getName();
title = title.substring(title.lastIndexOf('.') + 1);
jp.setBorder(new TitledBorder(title));
for (int i = 0; i < ids.length; i++) {
AbstractButton ab = new JButton("failed");
try {
// Get the dynamic constructor method
// that takes a String argument:
Constructor ctor = klass
.getConstructor(new Class[] { String.class });
// Create a new object:
ab = (AbstractButton) ctor.newInstance(new Object[] { ids[i] });
} catch (Exception ex) {
System.err.println("can't create " + klass);
}
bg.add(ab);
jp.add(ab);
}
return jp;
}
public void init() {
Container cp = getContentPane();
cp.setLayout(new FlowLayout());
cp.add(makeBPanel(JButton.class, ids));
cp.add(makeBPanel(JToggleButton.class, ids));
cp.add(makeBPanel(JCheckBox.class, ids));
cp.add(makeBPanel(JRadioButton.class, ids));
}
public static void main(String[] args) {
run(new ButtonGroups(), 500, 300);
}
public static void run(JApplet applet, int width, int height) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(applet);
frame.setSize(width, height);
applet.init();
applet.start();
frame.setVisible(true);
}
} ///:~
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