Using EntityManager in a SFSB method with a4j:Support action?

[oberiko.oberiko.gmail.com]

Hello.

Is there a way to use an EntityManager within a Stateful session bean method which has been called by an <a4j:support /> tag?


For example, assume I have two comboboxes and I want the values of them drive a query which will then populate a third.  The problem is that my EntityManager is coming up as null in my method when called from an <a4j:support action ="..." />. 

I can't help but feel I'm overlooking a simple solution.  Do I need to resubmit the entire form?  Is there any other way to grab the EntityManager?  Can I get the items from the database in another way? Am I overlooking a simple solution?

-------------------------------------------------------------------------
** JSF **
<h:selectOneMenu value="#{personName}">
  <f:selectItem itemValue=""/>
  <f:selectItem itemValue="Steve"/>
  <f:selectItem itemValue="John"/>
  <a4j:support event="onchange" action="#{directory.findPeople()}" reRender ="peopleMatch"/>
</h:selectOneMenu>

<h:selectOneMenu value="#{cityName}">
  <f:selectItem itemValue=""/>
  <f:selectItem itemValue="Toronto"/>
  <f:selectItem itemValue="Calgary"/>
  <a4j:support event="onchange" action="#{directory.findPeople()}" reRender ="peopleMatch"/>
</h:selectOneMenu>

<h:selectOneMenu id="peopleMatch" value="#{directory.foundPerson}">
  <s:selectItems value = "#{directory.matchingPeople}" var="mPers" label="#{mPers.toString()}" />
</h:selectOneMenu>

** SFSB **
@Stateful
@Name("directory")
@Scope(ScopeType.SESSION)
public class DirectoryBean implements Directory {

  @PersistenceContext(type = PersistenceContextType.EXTENDED)
  protected EntityManager entityManager;
  .
  .
  .

  public void findPeople() {
   if (personName == null || personName.length() == 0 || cityName == null
    || cityName.length() == 0)
      return;

    if (entityManager == null) 
      log.info("EntityManager is null?!"); //This is what's happening
    else {
      List <Person> matchingPeople = (List<Person>) entityManager.createQuery(
        "from Person p where name = :name and city = :city")
        .setParameter("name", personName)
        .setParameter("city", cityName)
        ;
    }  
}

[pgmjsd]

Are you sure you're using the same SFSB every time?  When does the conversation begin and end?

[oberiko.oberiko.gmail.com]

Since I have the SFSB in the SESSION scope, do I need to indicate a beginning and end?  I can refactor it a conversation instead if that helps.

[oberiko.oberiko.gmail.com]

I've put the SFSB into the CONVERSATION scope, but I still get the same problem.

** SFSB **
@Stateful
@Name("directory")
@Scope(ScopeType.CONVERSATION)
public class DirectoryBean implements Directory {

  @PersistenceContext(type = PersistenceContextType.EXTENDED)
  protected EntityManager entityManager;

  @RequestParameter protected Long directoryId;
  .
  .
  .
  //This method gets called from pages.xml on entering the page.
  public void load() {
    if (directoryId != null && (directory == null || directory.getId() != directoryId)){
      start();
      //Do loading stuff
    }
  }

  @Begin
  public void start() {
    log.info("Starting the conversation");
  }

  public void findPeople() {
   if (personName == null || personName.length() == 0 || cityName == null
    || cityName.length() == 0)
      return;

    if (entityManager == null)
      log.info("EntityManager is null?!"); //This is what's happening
    else {
      List <Person> matchingPeople = (List<Person>) entityManager.createQuery(
        "from Person p where name = :name and city = :city")
        .setParameter("name", personName)
        .setParameter("city", cityName)
        ;
    }

  @End
  public void saveDirectory(){
    //Save stuff
  }

  @End
  public void cancel() {}
}

[oberiko.oberiko.gmail.com]

Turns out I'm just blind.  I was missing a .getResultList() at the end of my query. 

After doing the conversation change it now usually works; seems a little random though.  (If it doesn't I restart JBoss, try again, and it usually does).