import java.awt.*;
import java.awt.event.*;  

public class NestedPanels2 extends NestedPanels
    implements ActionListener, ItemListener {
  public NestedPanels2() {
    // set up all of the buttons and what not
    super(); 

    // add the action listeners to the widgets
    choice.addItemListener(this); 
    beActionListener(this); 
    
  }

  // do this when the select box changes value   
  public void itemStateChanged(ItemEvent event)  {
    if (event!=null)
      System.out.println("ItemStateChanged: " + event); 
    Choice choice = (Choice) event.getSource();  
    if (choice != null)
      messageBar.setText("Choice selected: " + event.getItem()); 
  }

  // do this when a button is pressed
  public void actionPerformed(ActionEvent event) {
    if (event!=null)
      System.out.println("ActionPerformed: " + event); 
    Button source = (Button) event.getSource(); 
    if (source != null)
      messageBar.setText("Button pushed: " + source.getLabel()); 
  }

  // a recursive function that assigns action listeners
  // to all of the buttons.
  // uses the fact that a container can contain buttons.
  protected void beActionListener(Component comp) {
    if (comp != null) {
      if (comp instanceof Button) {
        // do this if you've got a button
        Button button = (Button) comp;
        button.addActionListener(this);  
      } else if (comp instanceof Container) {
        // get all of the sub components of the container
        // and call this recursively.
        Container container = (Container) comp; 
        int n = container.getComponentCount();
        for (int i = 0; i < n; i++)  
          beActionListener(container.getComponent(i));        
      }        
    }
  }
   
}