docs: protected void fireAttributeChange(AttributeChangeEvent event) {
  		if (this.listeners != null && isEventFirable()) {
  			final AttributeChangeListener[] list = new AttributeChangeListener[this.listeners.size()];
  			this.listeners.toArray(list);
  			for (final AttributeChangeListener listener : list) {
  				listener.onAttributeChangeEvent(event);
  			}
  		}
  	}