code: protected final void firePropertyChange(String propertyName,
              Object oldValue,
              Object newValue) {
          PropertyChangeSupport aChangeSupport = this.changeSupport;
          if (aChangeSupport == null) {
              return;
          }
          aChangeSupport.firePropertyChange(propertyName, oldValue, newValue);
      }
docs: Support for reporting bound property changes for Object properties. This method can be called
  when a bound property has changed and it will send the appropriate PropertyChangeEvent to any
  registered PropertyChangeListeners.
  
  @param propertyName the property whose value has changed
  @param oldValue the property's previous value
  @param newValue the property's new value