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

public class NestedPanels4 extends NestedPanels {
// notice we don't implement anything becuase we are going
// to delagate even handling to other classes

  public NestedPanels4() {
    // set up the UI
    super(); 

    // add the handlers
    // notice that we define the methods for 
    // each interface right after we create one.
    // its not intuitive but can be very powerful.
    choice.addItemListener(new ItemListener(){
		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()); 
    		}
        
    });
 
    // this function will call the "addActionListener()"
    // for each button in the UI.
    // we use the this reference to tell the function to
    // start at the top of the containment hierarchy.
    setActionListeners(this);
     
  }

  // the function that assigns action listeners to the buttons
  // recursively.      
  protected void setActionListeners(Component comp) {
    if (comp != null) {
      if (comp instanceof Button) {
        Button button = (Button) comp;
        button.addActionListener(new ActionListener(){
           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()); 
           }
        }); 
      } else if (comp instanceof Container) {
          Container container = (Container) comp; 
          int n = container.getComponentCount();
          for (int i = 0; i < n; i++)  
            setActionListeners(container.getComponent(i));        
      }        
    }
  }      
}