code: @Override
      public XPathSelector call() throws Exception {
          final Processor proc = new Processor(false);
          final Configuration config = proc.getUnderlyingConfiguration();
          final NodeInfo doc = new DocumentWrapper(mSession, config);
          final XPathCompiler xpath = proc.newXPathCompiler();
          final DocumentBuilder builder = proc.newDocumentBuilder();
          XPathSelector selector = null;
  
          try {
              final XdmItem booksDoc = builder.build(doc);
              selector = xpath.compile(mExpression).load();
              selector.setContextItem(booksDoc);
          } catch (final SaxonApiException e) {
              LOGGER.error("Saxon Exception: " + e.getMessage(), e);
              throw e;
          }
  
          return selector;
      }
docs: {@inheritDoc}