code: protected void indexNode(int expandedTypeID, int identity)
    {
  
      ExpandedNameTable ent = m_expandedNameTable;
      short type = ent.getType(expandedTypeID);
  
      if (DTM.ELEMENT_NODE == type)
      {
        int namespaceID = ent.getNamespaceID(expandedTypeID);
        int localNameID = ent.getLocalNameID(expandedTypeID);
  
        ensureSizeOfIndex(namespaceID, localNameID);
  
        int[] index = m_elemIndexes[namespaceID][localNameID];
  
        index[index[0]] = identity;
  
        index[0]++;
      }
    }
docs: Add a node to the element indexes. The node will not be added unless
  it's an element.
  
  @param expandedTypeID The expanded type ID of the node.
  @param identity The node identity index.