import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIDefaults;
import javax.swing.UIManager;
public class MainClass {
public static void main(String args[]) {
final String LABEL_FACTORY = "LabelFactory";
JFrame frame = new JFrame("Active Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
UIManager.put(LABEL_FACTORY, new ActiveLabel());
final JPanel panel = new JPanel();
JButton button = new JButton("Get");
ActionListener actionListener = new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
JLabel label = (JLabel)UIManager.get(LABEL_FACTORY);
panel.add(label);
panel.revalidate();
}
};
button.addActionListener(actionListener);
frame.add(panel, BorderLayout.CENTER);
frame.add(button, BorderLayout.SOUTH);
frame.setSize(200, 200);
frame.setVisible(true); }
}
class ActiveLabel implements UIDefaults.ActiveValue {
private int counter = 0;
public Object createValue(UIDefaults defaults) {
JLabel label = new JLabel(""+counter++);
return label;
}
}