Validation, Task Flow, Servlet, Pop-up, and a Managed Bean

Question

Hi,
We're trying to display a PDF in a pop-up by calling a Servlet within a JSF page by using a task flow in JDeveloper 11g R2.
The relevant JSF snippet:
<af:inlineFrame id="if1" shortDesc="Report" source="/pdfservlet" styleClass="AFStretchWidth"></af:inlineFrame>The /pdfservlet points to a Servlet with a doGet method as follows:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.reset();
  OutputStream out = response.getOutputStream();
  FacesContext context = this.getFacesContext(request, response);
  OracleReportBean bean =
    context.getApplication().evaluateExpressionGet(context, "#{reportBean}", OracleReportBean.class);
  bean.run(context, out);
  removeFacesContext();
  out.close();
}The Servlet attempts to get the FacesContext, but we've encountered the following exception:
Caused By: javax.faces.FacesException: Cant instantiate class: oracle.adfinternal.view.faces.component.AdfViewRoot.We removed the following lines from the getFacesContext() method:
UIViewRoot view = facesContext.getApplication().getViewHandler().createView(facesContext, "");
facesContext.setViewRoot(view);This avoids the exception above, however... We're trying to get the parameters from the form that was submitted. Here is an example element from the form:
<h:inputHidden value="MyMedicationList_Report" id="system_REPORT_RESOURCE"/>When the Servlet calls the Managed Bean to retrieve the value, it uses:
Map<String, String[]> requestParameters = getRequestParameters();
Parameters p = getParameters();
for( String key : requestParameters.keySet() ) {
  for( String value : requestParameters.get( key ) ) {
    int i = key.indexOf( ':' );
    if( i >= 0 ) {
      key = key.substring( i + 1 );
    p.put( key, value );
}Where getRequestParameters() attempts to get the external context to retrieve the request parameter values map:
return getExternalContext().getRequestParameterValuesMap();The map comes up empty.
I've tried following http://www.oracle.com/technetwork/developer-tools/adf/learnmore/oct2010-otn-harvest-183714.pdf by setting the web.xml to:
  <!-- JspFilter must be configured before adfBindings. -->
  <filter-mapping>
    <filter-name>JpsFilter</filter-name>
    <servlet-name>PDFServlet</servlet-name>
    <dispatcher>FORWARD</dispatcher>
    <dispatcher>INCLUDE</dispatcher>
    <dispatcher>REQUEST</dispatcher>
  </filter-mapping>
  <filter-mapping>
    <filter-name>adfBindings</filter-name>
    <servlet-name>PDFServlet</servlet-name>
    <dispatcher>FORWARD</dispatcher>
    <dispatcher>REQUEST</dispatcher>
  </filter-mapping>And set the data bindings to:
  <pageMap>
    <page path="/pdfservlet" usageId="ca_bcpra_promis_reporting_view_PDFServletPageDef"/>
  </pageMap>
  <pageDefinitionUsages>
    <page id="ca_bcpra_promis_reporting_view_PDFServletPageDef" path="ca.bcpra.promis.reporting.view.PDFServletPageDef"/>
  </pageDefinitionUsages>The Servlet executes, calls the instantiated managed bean, but cannot read the request parameters.
The button used to launch the task flow in a dialog is:
<af:commandButton text="Run Report" id="submitReport" useWindow="true"
                  windowEmbedStyle="inlineDocument" windowModalityType="applicationModal" windowHeight="500"
                  windowWidth="700" action="runReport"/>By using a task flow, the user inputs are validated before the pop-up is opened. We want to keep that behaviour. The PDF opens and then returns with a NullPointerException:
http://pastebin.com/raw.php?i=PaM64jL4
The Servlet, through the managed bean, makes a request to the report server to pass parameters and generate a PDF. The PDF is streamed back to the browser via the Servlet.
What other approaches can we take to:
1. Send user and system parameters.
2. Generate a PDF on a remote server.
3. Stream the PDF back to the user in a pop-up.
Thank you.

Answer 1

It is not a static PDF. The PDF is generated, dynamically, on the report server using the parameters from multiple forms on the page.
We've leveraged the HttpSession getSessionMap() object for now. When combined with a Method Task Flow, we can transfer the data (and FacesContext) to the report Servlet. For example, the following code exposes objects that the Servlet needs through the session:
  public void initReport(String reportName) {
    FacesContext context = FacesContext.getCurrentInstance();
    ExternalContext ec = context.getExternalContext();
    OracleReportBean bean =
      context.getApplication().evaluateExpressionGet(context, "#{reportBean}", OracleReportBean.class);
    bean.setFacesContext(context);
    ec.getSessionMap().put("reportBean", bean);
    ec.getSessionMap().put(Parameters.PARAM_REPORT_RESOURCE, reportName);
  }This means the Servlet can use the object:
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.reset();
    // Find the bean from the session.
    OracleReportBean bean = (OracleReportBean)request.getSession().getAttribute("reportBean");
    OutputStream out = response.getOutputStream();
    bean.run(out);
    out.close();
  }This allows the bean to generate reports.