How do I set the response status code for a request in ADF?

Question

For example:
I have a page accessible like page.jspx?id=$ID, in which $ID identifies an object stored in a database. The user navigates to page.jspx?id=abc. abc does not exist or has been deleted. I wish to set the response status code to 404 for the page request, like, for instance, https://docs.google.com/spreadsheet/ccc?key=abc does. How do I do this?
PS: Changing the status code for subsequent partial submits on the page if the object is deleted while the user is on the page (e.g. if the user attempts to delete an already deleted object through a "Delete" button on the page) may also be desirable, but would probably not fit in as well with the ADF lifecycle or be as useful.

Answer 1

Maybe I should be more specific about the current state of the code. It's something functionally similar in relevant portions to the following. For the purposes of this code, assume the ID maps only to a name, rather than a more complicated object:
page.jspx looks like:
<?xml version='1.0' encoding='utf-8'?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page"
     xmlns:f="http://java.sun.com/jsf/core"
     xmlns:af="http://xmlns.oracle.com/adf/faces/rich"
     xmlns:trh="http://myfaces.apache.org/trinidad/html" version="1.2">
     <jsp:directive.page contentType="text/html;charset=utf-8" />
     <f:view>
          <af:document binding="#{pageInitializer.dummyComponent}" title="#{pageData.name != null ? pageData.name : 'Object Not Found'}">
               <af:outputText rendered="#{pageData.name != null}" value="#{pageData.name}" />
               <af:outputText rendered="#{pageData.name == null}" value="No object was found at this URL." />
          </af:document>
     </f:view>
</jsp:root>pageInitializer and pageData are pageFlow-scoped beans with the following code:
class PageInitializer {
     @Inject private PageData pageData;
     @Inject private NameDao nameDao;
     @PostConstruct
     void initialize() {
          String name = nameDao.getNameById(FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("id"));
          if (name != null)
               pageData.setName(name);
          else
               // TODO: Set status code 404
     public void setDummyComponent(UIComponent dummyComponent) {
     public UIComponent getDummyComponent() {
          return null;
public class PageData {
     private String name;
     public String getName() {
          return name;
     public void setName(String name) {
          this.name = name;
}The code initializes the data from the database through the initilaizer of a pageFlow-scoped bean with a dummy setter for the document because I read somewhere that that would work, and it seems to work, even though it seems hacky.
Ideally, the code would render the 404 where it currently says (// TODO: Set status code 404). I realize this may not even be possible given the current architecture, because part of the response body has already been rendered, and I believe, but cannot find a source to cite, that the status code and headers cannot be set after the body has started being rendered. Is there any architecture that would get me this page's functionality (even if it's two JSPXs on the backend (which might be ideal)) and be able to render a 404 for an inexistent object?
Edited by: 907794 on Feb 1, 2012 3:55 PM
Edited by: 907794 on Feb 1, 2012 3:58 PM