Java Doc for ChangeTracker.java in  » Swing-Library » jgoodies-data-binding » com » jgoodies » binding » util » Java Source Code / Java DocumentationJava Source Code and Java Documentation

The tracker can observe readable bound bean properties if and only if the bean provides the optional support for listening on named properties as described in section 7.4.5 of the Java Bean Specification. The bean class must provide the following pair of methods:

 public void addPropertyChangeListener(String name, PropertyChangeListener l);
 public void removePropertyChangeListener(String name, PropertyChangeListener l);
 

Example:

 ChangeTracker tracker = new ChangeTracker();
 tracker.observe(address, "street");
 tracker.observe(address, "city");
 tracker.addPropertyChangeListener(new PropertyChangeListener() {
 public void propertyChange(PropertyChangeEvent evt) {
 System.out.println("Change state: " + evt.getNewValue());
 }
 });
 // Change the first ValueModel
 System.out.println(tracker.isChanged()); // Prints "false"
 address.setStreet("Belsenplatz");        // Prints "Change state: true"
 System.out.println(tracker.isChanged()); // Prints "true"
 tracker.reset();                         // Prints "Change state: false"
 System.out.println(tracker.isChanged()); // Prints "false"
 

Note: The classes BeanAdapter and PresentationModel already provide support for tracking changes. Typical binding code can use these classes and there seems to be no need to use the ChangeTracker.
author:
   Karsten Lentzsch
version:
   $Revision: 1.3 $
See Also:   ValueModel