code: private static void addRecursive(
          Object object, PropertyChangeListener propertyChangeListener)
      {
          addRecursive(object, propertyChangeListener, 
              new LinkedHashSet<Object>());
      }
docs: Recursively add the given property change listener to the given
  object and all its sub-objects
  
  @param object The object
  @param propertyChangeListener The property change listener