code: public Node getHashNode()
          throws TransformerException
      {
          Node hashNode = getExecutor().getNode(HASH_XPATH);
          if (hashNode == null)
          {
              hashNode = getExecutor().getDoc().createElementNS(GLOBAL_NS,
                  HASHVALUE);
              Attr algorithm = getExecutor().getDoc().createAttributeNS(GLOBAL_NS, HASH_ALGORITHM);
              algorithm.setValue(SHA_1);
              ((Element) hashNode).setAttributeNodeNS(algorithm);
              hashNode.appendChild(getExecutor().getDoc().createTextNode(""));
              Node header = getHeaderNode();
              header.insertBefore(hashNode, header.getFirstChild());
          }
          return hashNode;
      }
docs: Get the <code>&lt;glob:HashValue&gt;</code> Node. If the Node does not
  exist, create one and add it to the Document.
  
  @return A DOM Node representing the <code>&lt;glob:HashValue&gt;</code>
  tag in the XML document.