4 Replies Latest reply on Sep 24, 2010 5:30 AM by cash1981

Stateless default scope type

cash1981 Nov 3, 2009 11:32 AM

Hi.

From SiA lists the scope that is used for each type of component if
one is not specified in the component definition:

EJB stateful session bean Conversation
JPA entity class Conversation
EJB stateless session bean Stateless
EJB message driven bean Stateless
JavaBean (POJO) Event

Now this means that a @Stateless should have Stateless as default scope, however when I do @In on that with the scope present it doesnt work.

ie:

interface foo

@Stateless 
@Name("foo")
@AutoCreate
public class FooImpl implements Foo

Now lets say in a class you try to inject foo. This works fine.

@In Foo foo;

Now lets say I want to specify the scope directly

@In(scope=ScopeType.STATELESS) Foo foo;

The latter fails! Why? Shouldn't the scopetype be stateless?

1. Re: Stateless default scope type

asookazian Nov 4, 2009 5:41 AM (in response to cash1981)

I was able to reproduce the behavior using Seam 2.2.0.GA. Here is the root cause:

Caused by: java.lang.IllegalArgumentException: cannot specify explicit scope=STATELESS on @In: authenticator.foo
     at org.jboss.seam.Component.getValueToInject(Component.java:2314)
     at org.jboss.seam.Component.injectAttributes(Component.java:1736)
     at org.jboss.seam.Component.inject(Component.java:1554)
     at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:61)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.persistence.EntityManagerProxyInterceptor.aroundInvoke(EntityManagerProxyInterceptor.java:29)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.persistence.HibernateSessionProxyInterceptor.aroundInvoke(HibernateSessionProxyInterceptor.java:30)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
     at org.jboss.seam.intercept.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:50)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:597)
     at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:118)
     at org.jboss.ejb3.interceptor.EJB3InterceptorsInterceptor.invoke(EJB3InterceptorsInterceptor.java:63)
     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:54)
     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     at org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:126)
     ... 113 more

Why is it illegal to specify explicit scope=STATELESS on @In?

Additional experimentation reveals...

@In(create=true, scope=ScopeType.CONVERSATION)
    private Foo foo;

Caused by: java.lang.IllegalArgumentException: cannot combine create=true with explicit scope on @In: authenticator.foo
     at org.jboss.seam.Component.getValueToInject(Component.java:2307)
     at org.jboss.seam.Component.injectAttributes(Component.java:1736)
     at org.jboss.seam.Component.inject(Component.java:1554)
     at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:61)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.persistence.EntityManagerProxyInterceptor.aroundInvoke(EntityManagerProxyInterceptor.java:29)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.persistence.HibernateSessionProxyInterceptor.aroundInvoke(HibernateSessionProxyInterceptor.java:30)
     at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
     at org.jboss.seam.intercept.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:50)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:597)
     at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:118)
     at org.jboss.ejb3.interceptor.EJB3InterceptorsInterceptor.invoke(EJB3InterceptorsInterceptor.java:63)
     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:54)
     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
     at org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:126)
     ... 113 more

Why is this illegal?

2. Re: Stateless default scope type

cash1981 Nov 4, 2009 8:46 AM (in response to cash1981)

Hi Arbi, thanks for the reply.

My guess is that (and this is kinda far fetched), maybe Seam in Action has a typo here? Maybe the information is incorrect. Perhaps the default scope of a @Stateless is something entirely different.
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3. Re: Stateless default scope type

marcolof Sep 24, 2010 5:21 AM (in response to cash1981)

I ran into the same problem and ended up using the Seam Debug page to examine the content of the scopes:

For some reason, the default scope of a @Stateless EJB is.. the Application Context???

Seems like a bug to me! (I'm using 2.2.0.GA on a jBoss 5.1.0 GA server).
Any of the Seam developers have an answer for us?

Thanks!
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4. Re: Stateless default scope type

cash1981 Sep 24, 2010 5:30 AM (in response to cash1981)

Yes this is a bug, however it is not true that a stateless ejb is application context. Stateless ejb is Stateless. And the stateless scope is the first scope @In will search on. So its really no point in trying to speed things up by defining scope when it is stateless.
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