code: public NodeTypeIterator getMixinNodeTypes() throws RepositoryException
     {
        List<NodeTypeData> allNodeTypes = typesManager.getAllNodeTypes();
  
        Collections.sort(allNodeTypes, new NodeTypeDataComparator());
  
        EntityCollection ec = new EntityCollection();
        for (NodeTypeData nodeTypeData : allNodeTypes)
        {
           if (nodeTypeData.isMixin())
           {
              ec.add(new NodeTypeImpl(nodeTypeData, typesManager, this, locationFactory, valueFactory, dataManager));
           }
        }
        return ec;
     }
docs: Returns an iterator over all available mixin node types.
  
  @return An <code>NodeTypeIterator</code>.
  @throws RepositoryException if an error occurs.