add(new ArtifactTreeNode((Artifact) _object)) ;
treeModel.insertNodeInto(new ArtifactTreeNode((Artifact) _object, treeModel), this, getChildCount()) ;
	public void update (Observable _observable, Object _object)	{		if (_object instanceof Artifact)		{			if (product.getArtifacts().contains(_object))			{				add(new ArtifactTreeNode((Artifact) _object)) ;			}		}	}