e011. listening for a property change event.txt

这里面包含了一百多个JAVA源文件

A property change event is fired when a bound property is changed. 
    // Register for property change events on the bean
    bean.addPropertyChangeListener(new MyPropertyChangeListener());
    
    class MyPropertyChangeListener implements PropertyChangeListener {
        // This method is called every time the property value is changed
        public void propertyChange(PropertyChangeEvent evt) {
            // Get the old value of the property
            Object oldValue = evt.getOldValue();
    
            // Get the new value of the property
            Object newValue = evt.getNewValue();
        }
    }