Listening for a Vetoable Property Change Event
A vetoable property change event is fired when a constrained property
is changed. A listener can veto the change by throwing
PropertyVetoException and preventing the change.
// Register for property change events on the bean
bean.addVetoableChangeListener(new MyVetoableChangeListener());
class MyVetoableChangeListener implements VetoableChangeListener {
// This method is called every time the property value is changed
public void vetoableChange(PropertyChangeEvent evt) throws PropertyVetoException {
// Get the old value of the property
Object oldValue = evt.getOldValue();
// Get the new value of the property
Object newValue = evt.getNewValue();
// Determine if the change should be vetoed, thereby preventing the change
boolean veto = false;
if (veto) {
throw new PropertyVetoException("the reason for the veto", evt);
}
}
}
Post a comment