RE: [xsl] tomcat web server and dynamic XSL

[David.Pawson@xxxxxxxxxxx]

MK said.
    That's not the way it works. You have to write some servlet 
    code (or install some code that's already been written) 
    that uses the JAXP interface to invoke the transformation.

This is a part of a tomcat servlet I had working for the faq.

It may help. The full file pulls from mySQL too, but I don't think
that's of interest?

HTH DaveP


    /************************************************************/
   
    /**
     * Apply stylesheet to source document and display
     *@param style - stylesheet to use, as a string
     *@param source - Source XML file, as string
     *@param request
     *@param response 
     *@return void
     **/

    private void apply(String style, String source,
                           HttpServletRequest req, HttpServletResponse res)
                           throws TransformerException, java.io.IOException
{
                            
        //ServletOutputStream out = res.getOutputStream();
	//Above removed; reported
	//java.lang.IllegalStateException: getWriter() has already been
called for this response


        if (style==null) {
            out.println("No style parameter supplied");
            return;
        }
        if (source==null) {
            out.println("No source parameter supplied");
            return;
        }
        try {
            Templates pss = tryCache(style);
            Transformer transformer = pss.newTransformer();
            Properties details = pss.getOutputProperties();

            String mime =
pss.getOutputProperties().getProperty(OutputKeys.MEDIA_TYPE);
            if (mime==null) {
               // guess
                res.setContentType("text/html");
            } else {
                res.setContentType(mime);
            }

            Enumeration p = req.getParameterNames();
            while (p.hasMoreElements()) {
                String name = (String)p.nextElement();
                if (!(name.equals("style") || name.equals("source"))) {
                    String value = req.getParameter(name);
                    transformer.setParameter(name, new StringValue(value));
                }
            }
	
            // FIXME String path = getServletContext().getRealPath(source);
	    String path = getServletContext().getRealPath("N1553.1");
            if (path==null) {
                throw new TransformerException("Source file " + source + "
not found");
            }
            File sourceFile = new File(path);
            transformer.transform(new StreamSource(sourceFile), new
StreamResult(out));
        } catch (Exception err) {
            out.println(err.getMessage());
            err.printStackTrace();
        }

    }

    /**
    * Maintain prepared stylesheets in memory for reuse
    */
    private synchronized Templates tryCache(String url) 
	throws TransformerException, java.io.IOException {
        String path = getServletContext().getRealPath(url);
        if (path==null) {
            throw new TransformerException("Stylesheet " + url + " not
found");
        }
        
        Templates x = (Templates)cache.get(path);
        if (x==null) {
            TransformerFactory factory = TransformerFactory.newInstance();
// These two  calls to enable the resolver.
	    String r = "com.sun.resolver.tools.CatalogResolver";
	    factory.setURIResolver(makeURIResolver(r));

	    factory.setAttribute
("http://icl.com/saxon/feature/styleParserClass";,
	    "com.sun.resolver.tools.ResolvingXMLReader");  

	    // factory.setAttribute("STYLE_PARSER_CLASS",
	    // "com.sun.resolver.tools.ResolvingXMLReader");
	
//factory.setAttribute("com.icl.saxon.FeatureKeys.SOURCE_PARSER_CLASS",
	    //		 "com.sun.resolver.tools.ResolvingXMLReader");

	
factory.setAttribute("http://icl.com/saxon/feature/sourceParserClass";,
	
"com.sun.resolver.tools.ResolvingXMLReader");

	    
            x = factory.newTemplates(new StreamSource(new File(path)));
            cache.put(path, x);
        }
        return x;
    }

    /**
    * Clear the cache. Useful if stylesheets have been modified, or simply
if space is
    * running low. We let the garbage collector do the work.
    */

    private synchronized void clearCache() {
        cache = new Hashtable();
    }

    private Hashtable cache = new Hashtable();

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