JSF 2.0 where to initialize application wide dynamic collection?

Question

Hi everyone!
Suppose I am developing a website and on the main page I have a list of, say, articles. This list is the same for everyone.
This list is displayed using ui:repeat.
Where should I put the code that gets this list from the database? I want it to be loaded from the database each time someone opens the page, but not more often.
That's what I got:
@Named
@RequestScoped
public class ArticlesBean {
     @Inject
     private ArticlesDao articlesDao;
     private List<Article> allArticles;
     @PostConstruct
     public void initializeBean() {
          System.out.println("ArticlesBean @PostConstruct");
          allArticles = articlesDao.retrieveAllArticles();
     public List<Article> getAllArticles() {
          System.out.println("ArticlesBean getAllArticles");
          return allArticles;
     }But it's called too often (@PostConstruct when I enter the page and when I leave it; getAllArticles is sometimes called 2 times).
How do I go about it?
Edited by: M1keu on Jul 21, 2010 4:15 PM

Answer 1

M1keu wrote:
OK a word of clarification in case someone finds this post...
I used @Named instead of @ManagedBean and that gave me weird results. You should use @ManagedBean apparently (at least with @ViewScoped; then it would even be logical).
I used @ViewScoped and now my dynamic collection is refreshed upon entering the page (good), not refreshed upon leaving the page (good), not refreshed when validation fails (bad). If that bothers you as well, I'm trying to get some answers here: http://forums.sun.com/thread.jspa?threadID=5445656.
That would be what I would expect. When validation fails you keep the same view so a view-scoped bean would be preserved.
As to the session scoped bean I referred to earlier, I forgot half the trick (sorry about that). You have two beans, a request-scoped bean X and a session-scoped bean Y. Bean Y loads the actual data. Everything accesses the data through bean X. Every method in the bean X which accesses the list first calls a method to determine if the list should be reloaded. The method checks that FacesContext.getRenderResponse() is true and that the list has not been refreshed before; if both are true, reload the list from the database and set the flag to indicate the list has been reloaded. Since bean X is request-scoped, the flag gets reset automatically.