REST service: how to produce human readable output using XML + XSLT?

Question

I have a REST service implemented in GlassFish using Jersey. I have the service working using JSON output, now I would like to provide some human readable output as well. The most important thing missing in the JSON output is I want some fields in the statistics to be transformed to a clickable links, which would display a related statistics (using anoother REST call).

As I want to keep formatting and content separate, I do not want to produce HTML directly. I though using xml + xslt might be a sensible approach. I can use org.w3c.dom to produce a XML document, but I see no way how to attach a xslt to it.

Here is approximately what I do now:

@GET
@Path("history_id")
@Produces("application/xml")
public Document history(@QueryParam("id") String idText) throws ParserConfigurationException
{
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder docBuilder = factory.newDocumentBuilder();
        Document doc = docBuilder.newDocument();
        Element root = doc.createElement("root");
        doc.appendChild(root);
        Element el = doc.createElement(name);
        el.setTextContent(value);
        root.appendChild(el);
        return doc;

I would like following directive to appear in the XML produced:

<?xml-stylesheet type="text/xsl" href="history.xsl"?">

How can I specify a xslt to be attached to the XML? Or is my approach perhaps fundamentally wrong and this is usually done in some other way?

Just out of interest, why do you want to show the XML in a human readable way? Is it for displaying in part of a webpage (for example as part of an API visualizer, ie [Swagger](http://swagger.wordnik.com/) type approach) or is it for some other reason? — My Head Hurts, Dec 03 '12 at 10:10
@My Head Hurts I want to produce some statistics, which may be consumed by an application (this I currently do using JSON), but they might be sometimes inspected by a human as well, and for this I would like to add some formatting (most important is to implement clickable links on some fields to display related statistics) as a convenience. — Suma, Dec 03 '12 at 10:13
@MyHeadHurts It should be possible to provide a XML webpage with a XSLT stylesheet and web browser should be able to do the transformation and formatting on its side, line in http://www.w3schools.com/xml/simplexsl.xml. I understand I could do the transformation on the server, but somehow that feels like an inferior solution. — Suma, Dec 03 '12 at 10:27
Have you considered using JAXB to produce both XML and JSON from the same domain objects? Have a look at http://blog.bdoughan.com/2012/11/using-jaxb-with-xslt-to-produce-html.html and http://stackoverflow.com/a/11012294/116509 — artbristol, Dec 03 '12 at 10:33
@artbristol It seems like a reasonable way for many scenarios, but it does not seem to fit my purpose very well. 1) My output does not correspond directly to the database objects, I output some aggregated stats, not the objects themselves. 2) This seems to produce HTML, not XML. — Suma, Dec 03 '12 at 10:42
@MyHeadHurts I am trying to implement the solution in the link provided, but I do not see any XSLT attached to the DOM produced by the transformation. I will study it a bit more to understand it. If that works, it might be an answer. — Suma, Dec 03 '12 at 10:44
@MyHeadHurts I do not see any xslt being attach in the example. I am not sure I undestand it correctly, but the only output property set is indentation using transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4"); - am I missing something? — Suma, Dec 03 '12 at 10:51

score 3 · Accepted Answer · answered Dec 03 '12 at 11:16

That "directive" is called a "processing instruction" in the XML world. You can create one with the DOM API:

    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder docBuilder = factory.newDocumentBuilder();
    Document doc = docBuilder.newDocument();
    doc.appendChild(doc.createProcessingInstruction("xml-stylesheet", "type=\"text/xsl\" href=\"history.xsl\""));

Then, if you send the XML document to a browser/user agent that supports client-side XSLT it will apply the stylesheet to the XML.

REST service: how to produce human readable output using XML + XSLT?

1 Answers1