code: public void addItemPersistenceListener(ItemsPersistenceListener listener)
     {
        if (listener instanceof ExtendedMandatoryItemsPersistenceListener)
        {
           extendedMandatoryListeners.add((ExtendedMandatoryItemsPersistenceListener)listener);
        }
        else if (listener instanceof MandatoryItemsPersistenceListener)
        {
           mandatoryListeners.add((MandatoryItemsPersistenceListener)listener);
        }
        else
        {
           listeners.add(listener);
        }
        if (LOG.isDebugEnabled())
        {
           LOG.debug("Workspace '" + this.dataContainer.getName() + "' listener registered: " + listener);
        }
     }
docs: {@inheritDoc}