backing bean is invoked three times

[vdeminico]

Hi,
I'm observing this strange behaviour in my simple app... I have this xhtml fragment in my page:


"
<h:dataTable var="_member" value="#{utenteController.utentiList}">
         <h:column>
            <f:facet name="header">Name</f:facet>
            #{_member.nome}
         </h:column>
         <h:column>
            <f:facet name="header">Cognome</f:facet>
            #{_member.cognome}
         </h:column>
         <h:column>
            <f:facet name="header">Username</f:facet>
            #{_member.username}
         </h:column>
</h:dataTable>
"

and this is my backing bean:
"
@Named
public class UtenteController {
     @EJB UtenteService utenteService;
     private final Logger logger = Logger.getLogger(UtenteController.class);
     
     public List<Utente> getUtentiList()
     {
          logger.info("Invoco in Controller");
          return utenteService.retriveUtenteList();
     }
}
"

Looking at log file I observe that the controller is invoked three times... why?

Thanks,
Valerio.

[lightguard]

This is more of a JSF question. I think everyone that's done JSF development has seen this before. I'm honestly not sure why, but I suspect it has something to do with restoring the view, building up the component tree and rendering. Perhaps someone with more JSF in-depth knowledge will also respond.

[ratking]

You should change the bean as the following:

@Named
public class UtenteController {
    @EJB UtenteService utenteService;
    private List<Utente> utenteList;
    
    private final Logger logger = Logger.getLogger(UtenteController.class);
    public List<Utente> getUtentiList()
    {
        logger.info("Invoco in Controller");
        if (utenteList == null)
        {
            utenteList = utenteService.retriveUtenteList();
        }
    return utenteList;
    }
}

How-to: avoid method or getter to be called several times by caching result
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I think Jason is correct. If you also use the rendered tag also it will be called 6 times.