Generate PDF from memory and stream back via HTTP

Question

Hi All,
I'm attempting to generate a PDF report from data within a database using Oracle XML Publisher. Ultimately I want to have a page that has a button on it. When the user presses the button a "Download File" prompt will appear. From here the user can download a PDF report of the data in the database. Here is the code I have so far:
public void dataEngine() throws IOException, ParserConfigurationException,
SAXException, XSLException {
try {
Class.forName("oracle.jdbc.OracleDriver");
String url = "jdbc:oracle:thin:@dev:1521:ORCL";
java.sql.Connection jdbcConnection = DriverManager.getConnection(url,
"test", "test");
FOProcessor processor = new FOProcessor();
DataProcessor dataProcessor = new DataProcessor();
dataProcessor.setDataTemplate("C:/temp/catalogDataTemplate.xml");
FacesContext fctx = FacesContext.getCurrentInstance();
String templateTmpDir;
templateTmpDir = "C:/temp/catalogDataTemplate.xml";
Hashtable parameters = new Hashtable();
parameters.put("id", "catalog1");
dataProcessor.setParameters(parameters);
dataProcessor.setConnection(jdbcConnection);
// dataProcessor.setConnection(this.getCurrentConnection());
InputStream is;
is = fctx.getExternalContext().getResourceAsStream(templateTmpDir);
//dataProcessor.setOutput("catalogData.xml");
ByteArrayOutputStream os = new ByteArrayOutputStream();
dataProcessor.setOutput(os);
dataProcessor.processData();
os.close();
is.close();
HttpServletResponse response = (HttpServletResponse) fctx.getExternalContext().getResponse();
//MIME TYPE
response.setContentType("text/html");
InputStream xsl = null;
String tmpDir;
FacesContext fctx2 = FacesContext.getCurrentInstance();
tmpDir = "catalog.xsl";
xsl = fctx2.getExternalContext().getResourceAsStream(tmpDir);
String filename = "catalogreport.pdf";
response.setHeader("Content-Disposition", "attachment; filename=" + filename);
response.setContentType("application/binary");
OutputStream out = response.getOutputStream();
XSLProcessor p = new XSLProcessor();
processor.setOutputFormat(FOProcessor.FORMAT_PDF);
JXDocumentBuilderFactory factory = (JXDocumentBuilderFactory)JXDocumentBuilderFactory.newInstance();
JXDocumentBuilder documentBuilder = (JXDocumentBuilder) factory.newDocumentBuilder();
ByteArrayInputStream bis = new ByteArrayInputStream(os.toByteArray());
// Creates the in-memory representation of the output XML
XMLDocument xmlDocument = (XMLDocument) (documentBuilder.parse(bis));
XSLStylesheet xslSheet = p.newXSLStylesheet(xsl);
p.processXSL(xslSheet, xmlDocument, out);
out.flush();
out.close();
xsl.close();
fctx.responseComplete();
} catch (SQLException e) {
System.out.println("SQLException " + e.getMessage());
} catch (ClassNotFoundException e) {
System.out.println("ClassNotFoundException " + e.getMessage());
} catch (XDOException e) {
System.out.println("XDOException" + e.getMessage());
I keep getting a null pointer exception on the following line:
InputStream is = fctx.getExternalContext().getResourceAsStream(templateTmpDir);
Am I going in the right direction? Any suggestions would be greatly appreciated.
Thanks,
Tim

Answer 1

The bipublisher ide applies exactly to your situation.
You want to the following:
1. Run data template, generate some xml
2. Be able to apply a format template to the xml
3. Serve up the document on the screen in the form of a popup
This is all taken care with the bi publisher ide behind the scenes, specifically in the oaf download (note: I suggest you first get familiar with the standard version, BIPublisherIDE). The oaf version requires none of the coding effort your doing right now.
So let's work through how you would exactly do this. This is what you will need to do for an OAF Solution. For reference see
http://bipublisher.blogspot.com/2008/03/bi-publisher-bip-in-oa-framework-part.html. The code sample thats provided in the article you can clone for your purposes.
I highly recommend you invest a little time upfront understanding how the code works in the BIPublisherIDE. In the short term it might be painful to learn it, but in the long-term the code is free and you can modify however you would like, plus it works! The solution is all encompassing, best of all you can do everything locally without having to do anything server side for initial development (see the configuration options and manual on my blog)
===========================================================
step 1: Extended the bipublisher api class, call the super class.
import oracle.apps.xbol.bipublisher.api.XMLPublisherApi;
public class IPTInvoiceGenerator extends XMLPublisherApi
static oracle.apps.xdo.common.log.Logger logger;
public IPTInvoiceGenerator (OAPageContext pageContext, AppsContext appsContext, OAWebBean webBean)
/*call the super class, your connection will be set and stored in the config class
getOALookup is a local method that maps out your parameters values to the data template values
and may not work for your situation.
if this constructor doesn't meet your needs create a new constructor in each class all the
way down to the config class. To understand how the code works I suggest you visit and read
http://bipublisher.blogspot.com/2008/03/bi-publisher-bipublisheride.html
this will give you a great overview of the base classes and how you can morph them to your
needs. For anyone else reading this you should be able to create a new constructor for a concurrent
program with relative ease...
super(pageContext, appsContext, webBean, pageContext.getParameter("output"), getOALookup());
try
Steps 2-8 go here...
public final static Hashtable getOALookup()
Hashtable parameters = new Hashtable();
/**@Mapping:
*=================== OA Parameter | @BIP Parameter (see form function call =============
bi publisher ide will search oa parameters, get there values and map them to the data template parms.
parameters.put("P_MLOGO_ID" , "P_MLOGO_ID");
parameters.put("P_CONC_REQUEST_ID" , "P_CONC_REQUEST_ID");
parameters.put("P_DIR_PROJECT_ID" , "P_DIR_PROJECT_ID");
parameters.put("P_INDIR_PROJECT_ID" , "P_INDIR_PROJECT_ID");
parameters.put("P_INVOICE_NUMBER" , "P_INVOICE_NUMBER");
parameters.put("P_COST_PLUS_BILLING_ID" , "P_COST_PLUS_BILLING_ID");
parameters.put("P_TO_DATE" , "P_TO_DATE");
parameters.put("P_FROM_DATE" , "P_FROM_DATE");
parameters.put("P_ORDER_BY" , "P_ORDER_BY");
parameters.put("P_ORDER_BY_BILL_CODE" , "P_ORDER_BY_BILL_CODE");
parameters.put("orgId" , "P_ORG_ID");
parameters.put("P_DEBUG" , "P_DEBUG");
return parameters;
Step 2: Setup your output options
//Setup your output directory
setOutputDirectory(getFileDirectory(pageContext));
//Setup your file name.
setOutputFile("COSTPLUS_"+getRequestId());
Step 3: Setup your configured data template and format template that are in the template manager
tables in the eBusiness suite. Note: The code will download the data template and configured
format template automatically with no interaction.
//set data template code, no link is required to the format template
setXdoDataDefinitionCode("XXPO_INT_INVOICE");
setXdoDataDefinitionApplicationShortName("XBOL");
//setup format template code, no link is required to the data template
setXdoTemplateCode("XXPO_INT_INVOICE");
setXdoTemplateApplicationShortName("XBOL");
Step 4: Setup your parameters
setParameters(someHashTable);
Step 5: Call oaDataEngine(), create the xml document
oaDataEngine();
Step 6: Call applyTemplate(), apply the format template to the xml
applyTemplate()
Step 7: Display the document on the screen
displayOAFDocument(); //pop the document up on the browser
Step 8. Release the connection
finally
appsContext.releaseJDBCConnection();
That's it! I've used the code over 3 times for calling bipublisher reports from oracle forms6i. There is no need for a web service that I can think of, but perhaps there is something I overlooked...
Let me know if have any questions.
Ike Wiggins
http://bipublisher.blogspot.com