void (PropertyChangeEvent evt) { if (ContentImpl.PROP_CONTENT_MANAGER.equals(evt.getPropertyName())) { ContentManager oldValue = (ContentManager)evt.getOldValue(); ContentManager newValue = (ContentManager)evt.getNewValue(); if (oldValue != null) oldValue.removeContentManagerListener(BaseContentCloseListener.this); if (newValue != null) newValue.addContentManagerListener(BaseContentCloseListener.this); } }