Re: AW: Using Turbine's tools for assembling PDF output (using FOP): how to?

We have a solution that sounds similar. We are not a high volume site so 
  I am not sure how scalable this is since it creates a new Fop with 
each request. We extended VelocityOnlyLayout to create a PdfLayout:

public class PdfLayout extends VelocityOnlyLayout {

     FopFactory fopFactory = FopFactory.newInstance();
     TransformerFactory tFactory = TransformerFactory.newInstance();
     Log logger = LogFactory.getLog(PdfLayout.class);
     public void doBuild(RunData data) throws Exception {


         /* Screen string will store the XSL-FO */
         String screenString = "";

         /*
          * First, generate the screen and put the results into a string
         */
         ConcreteElement results = ScreenLoader.getInstance().eval(data, 
data.getScreen());
         if (results != null)
             screenString = results.toString();


         /**
          * Get the response object and set content type for PDF
          */

         HttpServletResponse response = data.getResponse();
         ByteArrayOutputStream out = new ByteArrayOutputStream();


         /**
          * Get a reader and instantiate the PDF Driver
          */
         StringReader reader = new StringReader(screenString);

         Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, out);



         try {

             /**
              * Render the document and write to the response
              */

             Source source = new StreamSource(reader);
             Result res = new SAXResult(fop.getDefaultHandler());
             Transformer transformer = tFactory.newTransformer();
             transformer.transform(source, res);

             byte[] byteContent = out.toByteArray();
             response.setContentType("application/pdf");
             response.setContentLength(byteContent.length);
             response.getOutputStream().write(byteContent);
             response.getOutputStream().flush();


         } catch (IllegalArgumentException e) {
             logger.error(e.getMessage());
             e.printStackTrace();
         } catch (TransformerException e) {
                 // Attempt to send the XSL-FO back to the browser for 
troubleshooting.
                 response.setContentType("text/xml");
                 PrintWriter writer = response.getWriter();
                 writer.print(screenString.toString());
                 writer.flush();
                 out.close();
                 logger.error("FOP Exception in PDFLayout "+ 
e.getMessage());
         } finally {
             out.close();
         }




     }

}

Here is our PdfScreen:

/**
      * This screen incorporates the security function (isAuthorized)
      * from VelocitySecureScreen, the only difference being the 
getLayout method, which returns PdfLayout if the user is authenticated.
      * See PdfLayout for the actual rendering of the PDF document
      */
public class PdfScreen extends VelocitySecureScreen {

     public String getLayout(RunData data) {

         boolean ok = false;
         String rv = null;

         try {
             ok = this.isAuthorized(data);
         } catch (Exception e) {
         }

         if (ok) {
             rv = "PdfLayout";
         } else {
             rv = "LoginLayout";
             data.setLayoutTemplate("/Login.vm");
         }

         return rv;

     }


}


Now whenever we need a PDF we extend PdfScreen and create the xsl-fo 
template.

Let me know if this is what you were looking for.

Steve Yokanovich



Alexander Zimmer wrote:
> Thank you both for your answers. 
> Anyway, I just would like to stress that the conversion FO->PDF and the streaming (via a RawScreen-like Screen) is not a problem and is already solved. 
> What I do not know (yet) is, how I can use Velocity plus all the nice Turbine pull tools for the Velocity template to assemble the FO input, such a template would look just like this (as you can see, a valid FO file, except the VTL sequences, which should be taken care of by Velocity):
> <?xml version="1.0" encoding="UTF-8"?>
> <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
>   <fo:layout-master-set>
>     <fo:simple-page-master master-name="simpleA4" page-height="29.7cm" page-width="21cm" margin-top="2cm" margin-bottom="2cm" margin-left="2cm" margin-right="2cm">
>       <fo:region-body/>
>     </fo:simple-page-master>
>   </fo:layout-master-set>
>   <fo:page-sequence master-reference="simpleA4">
>     <fo:flow flow-name="xsl-region-body">
>       <fo:block>Hello World, my name is $!{name}!</fo:block>
>       #foreach ($entry in $names)
>         <fo:block>Next name: $entry.Firstname $entry.Lastname</fo:block>
>       #end
>     </fo:flow>
>   </fo:page-sequence>
> </fo:root>
> How can I use template functionality? The problem involved are:
> 1. I want to use the Velocity engine and capture its output in a String/ByteArray. The output will be a valid FO file.
> 2. I want to be able to use all (at least: some) pull tools Turbine provides for screen templates
> I think that I've solved the other problems (how to do the streaming, how to convert into PDF, ...).
> I try to dive into the VelocityOnlyLayout (as Peter Courcoux pointed out), but if you have additional clues for me, I would be very happy to hear from you!
> 
> Cheers,
> Alex
> 
> 
> -----Ursprüngliche Nachricht-----
> Von: Jeffery Painter [mailto:[email protected]] 
> Gesendet: Freitag, 18. Jänner 2008 15:21
> An: Alexander Zimmer
> Betreff: Re: Using Turbine's tools for assembling PDF output (using FOP): how to?
> 
> 
> I haven't looked at this stuff in quite some time, but I had posted
> a PdfScreen that might give you a start on how to do things.
> 
> http://kiasoft.com/opensource/PdfScreen.java
> 
> I was using it with the iText library back in the day, but I believe your
> options are more varied now.
> 
> http://www.lowagie.com/iText/
> 
> good luck!
>