Access SessionScoped object from stateless EJB

Question

I do have a SessionScoped class. For each user access I need an own instance of this class. All went fine for a long time. But now I also need access to this objects from the backend without any user interaction. I do have a stateless enterprise bean but whenever I want to access the session scoped object I get an excepiton. A simple example code is as following:

@SessionScoped
public class SessionObj implements Serializable {

    public String getValue() {
        return "Hello World";
    }
}

@Stateless
public class StatelessBean {

    private static final Logger LOG=Logger.getLogger(StatelessBean.class);

    @Inject
    private SessionObj sessionObj;

    public void test() {
        LOG.info("session object: "+sessionObj);
        LOG.info("Method call: "+sessionObj.getValue());
    }

}

But calling the test method ends in an exception like:

12:19:10,484 ERROR [org.jboss.as.ejb3.tx.CMTTxInterceptor] (EJB default - 6)    javax.ejb.EJBTransactionRolledbackException: WELD-001303 No active contexts for scope type javax.enterprise.context.SessionScoped
12:19:10,484 ERROR [org.jboss.ejb3.invocation] (EJB default - 6) JBAS014134: EJB Invocation failed on component StatelessBean for method public void package.StatelessBean.test(): javax.ejb.EJBTransactionRolledbackException: WELD-001303 No active contexts for scope type javax.enterprise.context.SessionScoped
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleInCallerTx(CMTTxInterceptor.java:139) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInCallerTx(CMTTxInterceptor.java:204) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:306) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:190) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
    ...
Caused by: org.jboss.weld.context.ContextNotActiveException: WELD-001303 No active    contexts for scope type javax.enterprise.context.SessionScoped
    at org.jboss.weld.manager.BeanManagerImpl.getContext(BeanManagerImpl.java:598) [weld-core-1.1.5.AS71.Final.jar:2012-02-10 15:31]
    at org.jboss.weld.bean.proxy.ContextBeanInstance.getInstance(ContextBeanInstance.java:71) [weld-core-1.1.5.AS71.Final.jar:2012-02-10 15:31]
    at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:79) [weld-core-1.1.5.AS71.Final.jar:2012-02-10 15:31]
    at package.SessionObj$Proxy$_$$_WeldClientProxy.toString(SessionObj$Proxy$_$$_WeldClientProxy.java) [ws_core_job_manager.jar:]
    at java.lang.String.valueOf(String.java:2826) [rt.jar:1.6.0_21]
    at java.lang.StringBuilder.append(StringBuilder.java:115) [rt.jar:1.6.0_21]
    at package.StatelessBean.test(StatelessBean.java:29) [ws_core_job_manager.jar:]
    ...

So my question is: * Is there any option to access the object even without a session by any trick? * Is there any option to generate one session from within my stateless class?

I understand the cause of the exception but I want to have one 'global' session for this new usage of the existing code. In reallity of course it's not so easy and changing the session scoped code to a POJO and a session scoped container is not so easy.

Environment:

JDK 1.6
JBOSS 7.1.1

Solution:

As mentioned by Jan: Extend the StatelessBean as following:

@Stateless
public class StatelessBean {

    private static final Logger LOG=Logger.getLogger(StatelessBean.class);

    @Inject
    private BoundSessionContext sessionContext;

    @Inject
    private SessionObj sessionObj;

    public void test() {
        Map<String,Object> myMap=new HashMap<String,Object>();
        sessionContext.associate(myMap);
        sessionContext.activate();

        LOG.info("session object: "+sessionObj);
        LOG.info("Method call: "+sessionObj.getValue());

        sessionContext.invalidate();
        sessionContext.deactivate();
    }

}

And the example is working! Now I just have to understand the details ;-)

With your solution, the instance of `SessionObj` will be lost (become unreachable) when the call to `test` finishes, right? You'll get a new instance every time. Is that what you want? — Tom Anderson, Jul 18 '12 at 14:20
@Tom - there's no problem with the solution because the reference to `SessionObj` is proxied, — Jan Groth, Jul 18 '12 at 15:08

score 6 · Accepted Answer · answered Jul 18 '12 at 04:11

The problem is not to access to a session-scoped bean itself, the problem is that the session is not active, probably because it has never been started (e.g. EJB remoting).

What you can do is starting a BoundSessionContext manually, have a look here. I did that for conversations, and it worked fine.

score -3 · Answer 2 · answered Jul 17 '12 at 12:24

-3

you can't access session or store something in it with stateless beans, thats why they are called stateless! The only thing you can access is EjbContext, from it you can get caller principals and credencials, but don't forget to configure login module first.

answered Jul 17 '12 at 12:24

Ramanqul Buzaubak

493
4
14

1

That's not true. You can certainly inject a stateful object (like an authenticated user) into a stateless object. Technically you can even store stuff in SLSB, but of course you will have absolutely no guarantee that you'll be able to retrieve it.. – Jan Groth Jul 18 '12 at 04:07

Access SessionScoped object from stateless EJB

Solution:

2 Answers2

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