On Wed, 21 Sep 2005 05:29 pm, Jeremias Maerki wrote:
> On 21.09.2005 11:21:50 ALi wrote:
> > this is my code ...
> > xml is in resultstr (<?xml ...........>)
> > xslt is the name of the file (/name.file.xsl)
> > long tiempo1 = System.currentTimeMillis();
> > long tiempo2 = 0;
> > // Construct fop with desired output format
> > Driver driver = new Driver();
> > driver.setRenderer(Driver.RENDER_PDF);
> > // Setup output
> > try {
> > java.io.ByteArrayOutputStream out = new
> > java.io.ByteArrayOutputStream(); //out = new
> > java.io.BufferedOutputStream(out);
> > try {
> > driver.setOutputStream(out);
> > // Setup XSLT
> > TransformerFactory factory = TransformerFactory.newInstance();
> > Transformer transformer = factory
> > .newTransformer(new StreamSource(xsltfile));
>
> That's exactly it. You reload the stylesheet every time. If you
> create a stylesheet cache, you can simply reuse Templates instances.
>
Why would cacheing the stylesheet make the first invocation faster? The
original question was about executing a transformation multiple times
in a loop and why the first invocation takes so much longer than the
second and by the 3rd execution times becomes stable. I still think
these time differences are solely JVM/application startup/warmup
related and have nothing to do with cacheing the stylesheet as that
would only make subsequent invocations faster.
Manuel
> //Create the Templates object and store it in the cache
> Templates templates = factory.newTemplates(new
> StreamSource(xsltfile));
>
> //To create the Transformer with the Templates objects from the cache
> Transformer transformer = templates.newTransformer();
>
> > // Set the value of a <param> in the stylesheet
> > transformer.setParameter("versionParam", "2.0");
> > // Setup input for XSLT transformation
> > Source src = new StreamSource(new StringReader(resultStr));
> > // Resulting SAX events (the generated FO) must be piped through to
> > FOP Result res = new SAXResult(driver.getContentHandler());
> > // Start XSLT transformation and FOP processing
> > transformer.transform(src, res);
> > tiempo2 = System.currentTimeMillis();
> > response.setContentType("application/pdf");
> > byte[] cont = out.toByteArray();
> > response.setContentLength(cont.length);
> > response.getOutputStream().write(cont);
> > response.getOutputStream().flush();
> > } catch (TransformerException e) {
> > logger.warn("Error generando pdf :" + e.getMessage());
> > } finally {
> > out.close();
> > }
> > } catch (FileNotFoundException e) {
> > e.printStackTrace();
> > } catch (IOException e) {
> > logger.debug("Error cerrando el fichero " + e.getMessage());
> > }
> > logger.info("Tiempo 1:" + tiempo1);
> > logger.info("Tiempo 2:" + tiempo2);
> > logger.info("Total :" + (tiempo2 - tiempo1));
> >
> > On 9/21/05, Jeremias Maerki <[EMAIL PROTECTED]> wrote:
> > > I assume the operating system has very little influence on the
> > > time here. The fact that ALi has a big difference in the first
> > > couple of invocations is a clear indicator that he experiences
> > > the effect of class loading and just-in-time compiling by the
> > > JavaVM. And yes, ALi, the stylesheets have to be "compiled" (or
> > > at least parsed) but I guess from your code that this happens
> > > each time in your case. Unfortunately, we don't see the code of
> > > your makePDF() method.
> > >
> > > You can reuse the "pre-compiled" XSLT stylesheet if you use the
> > > JAXP Templates object. Please note that it's not FOP that
> > > compiles the XSLT stylesheet. It's probably you in makePDF() by
> > > using JAXP. FOP only processes the output of the XSL
> > > transformation. There are lots of articles on the web (like the
> > > following) that demonstrate how to cache Templates instances:
> > > http://www.javaworld.com/javaworld/jw-05-2003/jw-0502-xsl.html
> > >
> > > On 21.09.2005 10:22:22 Manuel Mall wrote:
> > > > Are you sure its not your operating system which causes the
> > > > time differences. Even OSes tend to warm up, ie. the first time
> > > > around existing stuff gets swapped out and the new code loaded.
> > > > Next time around this is not required any more.
> > > >
> > > > Manuel
> > > >
> > > > On Wed, 21 Sep 2005 04:07 pm, ALi wrote:
> > > > > Hello i have problems with times in generating pdf
> > > > > I want to know why the times are so different between one
> > > > > invocation and two
> > > > >
> > > > >
> > > > > for example i have the class makePDF
> > > > >
> > > > > main () {
> > > > > time1
> > > > > makePDF(xml,xsl);
> > > > > time2
> > > > > println(time2-time1)
> > > > > }
> > > > > the times are over 8 seconds
> > > > > more or less (with my xsl)
> > > > >
> > > > > if i have
> > > > > main () {
> > > > > for (1-10) {
> > > > > time1
> > > > > makePDF(xml,xsl);
> > > > > time2
> > > > > println(time2-time1)
> > > > > }
> > > > > }
> > > > >
> > > > > the first time is 8 seconds, but the seconds ones are less
> > > > > but much less the second is 3 seconds the third 1500
> > > > > miliseconds and after over 300 miliseconds .....
> > > > > why is these? is it because the fop need to compile the xsl?
> > > > > Are any form to force to cache the compilation of xsl? (in
> > > > > order to always take the same time.
> > > > >
> > > > > We have different xsl and one class that makes alls
> > > > >
> > > > >
> > > > > thx for your help
> > >
> > > Jeremias Maerki
> > >
> > > many thx for the url jeremias
>
> Jeremias Maerki
>
>
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