931: Mainline

With the property-change mechanism incorporated into the form, you can define a form listener to be activated by property-change events.

That listener implements the PropertyChangeListener interface, which requires the definition of the propertyChange method and the importation of the java.beans package.

The propertyChange method determines the property name from an instance of the PropertyChangeEvent class using the getPropertyName method. Then, acting typically, the propertyChange method fetches information from the form and relays that information to a model. The constructor ensures that the required movie application is in hand, ready to produce the currently selected movie model:

import java.beans.*; 
public class RatingPanelListener implements PropertyChangeListener { 
 private MovieApplication applet; 
 public RatingPanelListener(MovieApplication a) { 
  applet = a; 
 } 
 public void propertyChange (PropertyChangeEvent e) { 
  String property = e.getPropertyName(); 
  if (applet.getMovie() instanceof Movie) { 
   if      (property.equals("value1")) { 
    applet.getMovie().setScript(applet.getForm().getValue1()); 
   } 
   else if (property.equals("value2")) { 
    applet.getMovie().setActing(applet.getForm().getValue2()); 
   } 
   else if (property.equals("value3")) { 
    applet.getMovie().setDirection(applet.getForm().getValue3()); 
   } 
  } 
 } 
}