code: @Override
      public Set<Node> check(Set<Node> nodes, Node root) throws NodeSelectorException {
          Assert.notNull(nodes, "nodes is null!");
          this.nodes = nodes;
  
          //Document doc = (root instanceof Document) ? (Document) root : DOMHelper.getOwnerDocument(root);
          caseSensitive = false;  //!doc.createElement("a").isEqualNode(doc.createElement("A"));
  
          result = new LinkedHashSet<Node>();
          switch (selector.getCombinator()) {
          case DESCENDANT:
              addDescendantElements();
              break;
          case CHILD:
              addChildElements();
              break;
          case ADJACENT_SIBLING:
              addAdjacentSiblingElements();
              break;
          case GENERAL_SIBLING:
              addGeneralSiblingElements();
              break;
          }
          
          return result;
      }
docs: {@inheritDoc}