Generating PDF from Flex BarChart

Question

Hello,
I am new to Flex. Have been playing with creating Advanced
Data Grid and Bar Charts for our application prototype and would
like to explore how to create a PDF file of the BarChart or other
charting components.
The requirement is simple. We show the BarChart and a button
to view it as a PDF. When the user presses the button, the PDF
viewing dialog should come up and the user can opt to save the PDF
or view it (the standard way a browser deals with the PDF).
Have read blogs, this forum and LiveCycle docs but don't
understand clearly how Flex communicates with
LiveCycle ES (or PDF Generator) to display the PDF. Any ideas
or tutorials that does this would be appreciated.
Thanks,
Kannan

Answer 1

In order to generate a PDF document, you have to call a
method on a Java remote object that uses the XFAHelper and pass it
some arguments.
I modified the PDFService example in the documentation so I
can:
1- specify any document as opposed to hardcoding the PDF
template name
2- write the PDF to a file as opposed to writing it in the
user's session
Here is the source:
package com.mycompany.flex.remoteObjects;
import java.io.File;
import java.io.IOException;
import org.w3c.dom.Document;
import flex.acrobat.pdf.XFAHelper;
import flex.messaging.FlexContext;
import flex.messaging.util.UUIDUtils;
public class PDFService
public PDFService()
public Object generatePDF(Document dataset, String
PDFdocument) throws IOException
// Open shell PDF
String source =
FlexContext.getServletContext().getRealPath("/pdfgen/" +
PDFdocument);
int index = source.indexOf("./");
if(index != -1 )
// Remove the ./ added by UNIX
source = source.substring(0, index) + source.substring(index
+ 2, source.length());
XFAHelper helper = new XFAHelper();
helper.open(source);
// Import XFA dataset
helper.importDataset(dataset);
// Create a unique ID
String uuid = UUIDUtils.createUUID(false);
source =
FlexContext.getServletContext().getRealPath("/dynamic-pdf/" + uuid
+ "_" + PDFdocument);
index = source.indexOf("./");
if(index != -1 )
// Remove the ./ added by UNIX
source = source.substring(0, index) + source.substring(index
+ 2, source.length());
// Create the file object
File file = new File(source);
// Save the file
helper.save(file);
// Close any resources
helper.close();
return (uuid + "_" + PDFdocument);
pdfgen is the folder where my PDF template resides.
dynamic-pdf is the folder where the generated PDF are saved.
These two folders are located under flex.war at the first
level.
In Flex, I wrote a Cairngorm command that calls this remote
object and displays the generated PDF:
package com.mycompany.core.commands
import com.adobe.cairngorm.commands.ICommand;
import com.adobe.cairngorm.control.CairngormEvent;
import com.adobe.cairngorm.business.Responder;
import
com.mycompany.core.business.GenerateAndOpenPDFDelegate;
import
com.mycompany.core.control.event.GenerateAndOpenPDFEvent;
import com.mycompany.core.model.ModelLocator;
import flash.net.navigateToURL;
import flash.net.URLRequest;
import mx.rpc.events.ResultEvent;
import mx.rpc.events.FaultEvent;
import mx.collections.*;
import mx.core.Application;
import mx.controls.Alert;
public class GenerateAndOpenPDFCommand implements ICommand,
Responder
[Bindable]
private var model:ModelLocator = ModelLocator.getInstance();
public function GenerateAndOpenPDFCommand():void
public function execute(event:CairngormEvent):void
trace("Executing GenerateAndOpenPDFCommand...");
var delegate : GenerateAndOpenPDFDelegate = new
GenerateAndOpenPDFDelegate( this );
var generateAndOpenPDFEvent : GenerateAndOpenPDFEvent =
event as GenerateAndOpenPDFEvent;
delegate.generateAndOpenPDF( generateAndOpenPDFEvent.pdfVO
public function onResult( event : * = null ) : void
var item:Object;
var result:String = (event as ResultEvent).result as String;
trace("GenerateAndOpenPDFCommand::onResult\n\n" + result);
if (result)
// Open the generated PDF in a new window
navigateToURL(new URLRequest(ModelLocator.FLEX_URL +
"dynamic-pdf/" + result), "_blank");
// Hide the progress bar overlay
Application.application.requestProgressBar.visible = false;
Application.application.requestProgressBar.progressBar.source =
null;
Application.application.requestProgressBar.progressBar.label
= this.model.languageDictionary["000012"];
public function onFault( event : * = null ) : void
// Hide the progress bar overlay
Application.application.requestProgressBar.visible = false;
Application.application.requestProgressBar.progressBar.source =
null;
// Debug
Alert.show("GenerateAndOpenPDFCommand:\n\n" + (event as
FaultEvent).message);
FLEX_URL is created in this way some place else in the
application:
// Get the server URL from the Application's
var server:String = Application.application.url;
var index:uint = server.indexOf("Shell"); // Shell is the
name of my app folder
server = server.substring(0, index);
// This is the flex.war/ URL
ModelLocator.FLEX_URL = server;
Of course, it would be better to save the PDF in the user's
session as Adobe suggests, but I couldn't figure out how they use
the PDFResourceServlet. First of all, I had to get its code.
I had to decompile the java class files in the samples to get
the source of the PDFResourceServlet as it is not in the
documentation. Here it is:
package com.mycompany.flex.remoteObjects;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class PDFResourceServlet extends HttpServlet
public PDFResourceServlet()
protected void doGet(HttpServletRequest req,
HttpServletResponse res)
throws ServletException, IOException
doPost(req, res);
protected void doPost(HttpServletRequest req,
HttpServletResponse res)
throws ServletException, IOException
String id = req.getParameter("id");
if(id != null)
HttpSession session = req.getSession(true);
try
byte bytes[] = (byte[])(byte[])session.getAttribute(id);
if(bytes != null)
res.setContentType("application/pdf");
res.setContentLength(bytes.length);
res.getOutputStream().write(bytes);
} else
res.setStatus(404);
catch(Throwable t)
System.err.println(t.getMessage());
private static final long serialVersionUID =
0x7180e4383e53d335L;