code: protected void beforeMaterialization()
  	{
  		if (_listeners != null)
  		{
  			MaterializationListener listener;
  
  			for (int idx = _listeners.size() - 1; idx >= 0; idx--)
  			{
  				listener = (MaterializationListener) _listeners.get(idx);
  				listener.beforeMaterialization(this, _id);
  			}
  		}
  	}
docs: Calls beforeMaterialization on all registered listeners in the reverse
  order of registration.