Hi Jason,

Thanks for the response. I'm seeing it in the development environment.
I can't even get ahold of a stack trace in production because the
logged events I try to throw just aren't reaching the Logs manager. I
do know that it's not working, however, because the object doesn't get
inserted in the following code.

Here's some sample code to show what's happening, and a stack trace of
the error it throws

public class SessionListener implements HttpSessionListener {
        private static final Logger log = Logger
                        .getLogger("DataNucleus.JDO");
        @Override
        public void sessionCreated(HttpSessionEvent ev) {
                System.out.println("Session starting");
                ev.getSession().setMaxInactiveInterval(2);
        }

        @Override
        public void sessionDestroyed(HttpSessionEvent ev) {
                try {
                        System.out.println("Session ending");
                        PersistenceManager pm = 
PMF.get().getPersistenceManager();
                        System.out.println(pm);
                        PersistMe me = new PersistMe();
                        me.setName("Erem");
                        pm.makePersistent(me);
                        pm.close();
                        System.out.println("Session ended");
                } catch (Exception e) {
                        log.log(Level.SEVERE, "Failed in session cleanup", e);
                }
        }
}

This code, when run from the dev server makes this error

Sep 11, 2009 3:50:53 PM lotr.server.SessionListener sessionDestroyed
SEVERE: Failed in session cleanup
java.lang.NullPointerException: No API environment is registered for
this thread.
        at
com.google.appengine.api.datastore.DatastoreApiHelper.getCurrentAppId
(DatastoreApiHelper.java:63)
        at
com.google.appengine.api.datastore.DatastoreApiHelper.getCurrentAppIdNamespace
(DatastoreApiHelper.java:73)
        at com.google.appengine.api.datastore.Key.<init>(Key.java:100)
        at com.google.appengine.api.datastore.Key.<init>(Key.java:85)
        at com.google.appengine.api.datastore.Key.<init>(Key.java:81)
        at com.google.appengine.api.datastore.Entity.<init>(Entity.java:103)
        at com.google.appengine.api.datastore.Entity.<init>(Entity.java:84)
        at org.datanucleus.store.appengine.DatastoreFieldManager.<init>
(DatastoreFieldManager.java:167)
        at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject
(DatastorePersistenceHandler.java:178)
        at org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent
(JDOStateManagerImpl.java:3185)
        at org.datanucleus.state.JDOStateManagerImpl.makePersistent
(JDOStateManagerImpl.java:3161)
        at org.datanucleus.ObjectManagerImpl.persistObjectInternal
(ObjectManagerImpl.java:1298)
        at org.datanucleus.ObjectManagerImpl.persistObject
(ObjectManagerImpl.java:1175)
        at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent
(JDOPersistenceManager.java:669)
        at org.datanucleus.jdo.JDOPersistenceManager.makePersistent
(JDOPersistenceManager.java:694)
        at lotr.server.SessionListener.sessionDestroyed(SessionListener.java:
26)
        at org.mortbay.jetty.servlet.AbstractSessionManager.removeSession
(AbstractSessionManager.java:661)
        at org.mortbay.jetty.servlet.AbstractSessionManager$Session.timeout
(AbstractSessionManager.java:918)
        at org.mortbay.jetty.servlet.HashSessionManager.scavenge
(HashSessionManager.java:200)
        at org.mortbay.jetty.servlet.HashSessionManager.access$000
(HashSessionManager.java:36)
        at org.mortbay.jetty.servlet.HashSessionManager$1.run
(HashSessionManager.java:144)
        at java.util.TimerThread.mainLoop(Unknown Source)
        at java.util.TimerThread.run(Unknown Source)

On Sep 11, 11:37 am, "Jason (Google)" <apija...@google.com> wrote:
> Hi Erum. Are you seeing this error in the development environment or in
> production?
>
> - Jason
>
> On Wed, Sep 9, 2009 at 5:43 PM, Erem <ehb...@gmail.com> wrote:
>
> > Hey All,
>
> > What is the best way to tie into session destruction events?
>
> > I have implemented an HttpSessionListener and put it in my web.xml.
> > The SessionListener gets called, but any attempt to do DataStore or
> > URLFetch API calls within sessionDestroyed results in errors.
>
> > For example, the JDO API throws:
>
> > Exception in thread "Timer-125" java.lang.NullPointerException: No API
> > environment is registered for this thread.
> >        at
> > com.google.appengine.api.datastore.DatastoreApiHelper.getCurrentAppId
> > (DatastoreApiHelper.java:63)
> >        at com.google.appengine.api.datastore.QueryTranslator.convertToPb
> > (QueryTranslator.java:35)
>
> > My app has constructs of "Visitors" (anyone who comes to the site) and
> > "Users" (verified accounts). The former's data get stored in sessions,
> > the latter explicitly in the datastore.
>
> > Every User has an ArrayList<Visitor>, listing the visitors currently
> > logged in to the User's account.
>
> > When a session is destroyed, meaning a Visitor has left, I want to
> > remove that visitor from the user's "Logged in" ArrayList.
>
> > Having trouble thinking of another way to do it =(
>
> > Any advice would be much appreciated.
>
> > Erem
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