Java by API/javax.swing.event/InternalFrameEvent

InternalFrameEvent: getSouce()

import java.awt.BorderLayout;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
import javax.swing.event.InternalFrameAdapter;
import javax.swing.event.InternalFrameEvent;
import javax.swing.event.InternalFrameListener;
public class MainClass {
  public static void main(final String args[]) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JDesktopPane desktop = new JDesktopPane();
    JInternalFrame internalFrames[] = {
        new JInternalFrame("Can Do All", true, true, true, true),
        new JInternalFrame("Not Resizable", false, true, true, true),
        new JInternalFrame("Not Closable", true, false, true, true),
        new JInternalFrame("Not Maximizable", true, true, false, true),
        new JInternalFrame("Not Iconifiable", true, true, true, false) };
    InternalFrameListener internalFrameListener = new InternalFrameIconifyListener();
    int pos = 0;
    for (JInternalFrame internalFrame : internalFrames) {
      desktop.add(internalFrame);
      internalFrame.setBounds(pos * 25, pos * 25, 200, 100);
      pos++;
      internalFrame.addInternalFrameListener(internalFrameListener);
      
      JLabel label = new JLabel(internalFrame.getTitle(), JLabel.CENTER);
      internalFrame.add(label, BorderLayout.CENTER);
      internalFrame.setVisible(true);
    }
    frame.add(desktop, BorderLayout.CENTER);
    frame.setSize(500, 300);
    frame.setVisible(true);
  }
}
class InternalFrameIconifyListener extends InternalFrameAdapter {
  public void internalFrameIconified(InternalFrameEvent internalFrameEvent) {
    JInternalFrame source = (JInternalFrame)internalFrameEvent.getSource();
    System.out.println ("Iconified: " + source.getTitle());
  }
  public void internalFrameDeiconified(InternalFrameEvent internalFrameEvent) {
    JInternalFrame source = (JInternalFrame)internalFrameEvent.getSource();
    System.out.println ("Deiconified: " + source.getTitle());
  }
}