code: private URIResolver createStyleSheetResolver(CatalogResolver catalogResolver) throws MojoExecutionException {
  		URIResolver uriResolver;
  		try {			
  			URL url = getNonDefaultStylesheetURL() == null ? getDefaultStylesheetURL() : getNonDefaultStylesheetURL();
  			if (getLog().isDebugEnabled()) {
  			    getLog().debug("Using stylesheet: " + url.toExternalForm());
  			}
  			uriResolver = new StylesheetResolver("urn:docbkx:stylesheet", new StreamSource(url.openStream(), url
  					.toExternalForm()), catalogResolver);
  		} catch (IOException ioe) {
  			throw new MojoExecutionException("Failed to read stylesheet.", ioe);
  		}
  		return uriResolver;
  	}
docs: Creates an URI resolver to handle <code>urn:docbkx:stylesheet(/)</code> as a special URI. This URI points to the
  default docbook stylesheet location
  
  @param catalogResolver The initial resolver to use
  @return The Stylesheet resolver.
  @throws MojoExecutionException If an error occurs while reading the stylesheet