"main program" method - construct and show
if (av.length == 0) {
System.err.println("Usage: CompTest ComponentSubclass");
System.exit(1);
}
String name = av[0];
// create an instance of class named in "name", save in "Component c".
Component c = null;
try {
Class cf = Class.forName(name);
Object o = cf.newInstance();
if (!(o instanceof Component)) {
System.err.println("ERROR: Class " + name +
" is not a subclass of Component");
System.exit(1);
}
c = (Component)o;
} catch (Exception e) {
System.err.println("Component under test got exception in construction or initialization");
System.err.println(e.toString());
System.exit(1);
}
// create a Frame, and "Component c" to it.
final JFrame f = new JFrame("CompTest: " + av[0]);
Container cp = f.getContentPane();
cp.add(BorderLayout.CENTER, c); // Add the component under test
JButton quitButton;
cp.add(BorderLayout.SOUTH, quitButton = new JButton("Exit"));
quitButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
f.setVisible(false);
f.dispose();
System.exit(0);
}
});
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Set things reasonably sized.
Dimension d = c.getPreferredSize();
if (d.width == 0 || d.height == 0) {
// component doesn't have getPreferredSize() yet, hard code a size.
f.setSize(300, 200);
} else {
f.pack();
}
f.setLocation(200, 200);
f.setVisible(true);
