Cant use EntityManager into Converter

[villo]

Hi there

I'm experimenting a bit with seam, but I'm currently stuck on this issue...

I building a simple questionaire page; one has a list of questions with radio answers.

In order to display answers like:

 <h:column>
 <f:facet name="Answer">
 <h:outputText value="Answers"/>
 </f:facet>
 <h:selectOneRadio value="#{question.selectedAnswer}" converter="#{ansbean.converter}">
 <f:selectItems value="#{question.answerMap}" />
 </h:selectOneRadio>
 </h:column>

I had to write a converter bean, along the lines of the one in the dvd store example. This is basically

@Stateful
@Name("ansbean")
@Scope(ScopeType.APPLICATION)
@Interceptors(SeamInterceptor.class)
public class AnswersBean implements Answers {

 Logger log = Logger.getLogger(Register.class);
 List<Answer> answers;
 Map<String, Answer> answersMap;

 @PersistenceContext(type=EXTENDED)
 EntityManager em;

 @Create
 public void loadData(){
 //load some stuff from db
 }
 public Converter getConverter() {
 return new AnswerConverter(em);
 }

 static public class AnswerConverter implements Converter, Serializable {

 Logger log = Logger.getLogger(AnswerConverter.class);
 private EntityManager em;

 public AnswerConverter(EntityManager em) {
 this.em = em;
 }

 public Object getAsObject(FacesContext facesContext,
 UIComponent uiComponent,
 String value) throws ConverterException {

 if ((value == null) || value.length() == 0) {
 return null;
 }

 log.info("INTO CONVERTER Asobject()");

 int id = Integer.valueOf(value).intValue();

 Answer ret = null;
 ret = (Answer) em.createQuery("from Answer where id=?").setParameter(0,id).getSingleResult();
 return ret;
 }

 public String getAsString(FacesContext facesContext,
 UIComponent uiComponent,
 Object object) throws ConverterException {
 if (object == null) return null;

 return String.valueOf(((Answer) object).getId());

 }
 }
}

In my Question entity bean (one to many relationship with Answer) I have
created an helper method like

 @Transient
 public Map<String, Answer> getAnswerMap(){
 Map<String, Answer> results = new TreeMap<String, Answer>();

 for (Answer answer : answers) {
 result.put(answer.getText(), answer);
 }

 answerMap = results;
 return answerMap;
 }

The page loads the questionaire fine, but when I submit it I get the following trace:

11:32:32,734 ERROR [AnswersBean$AnswerConverter] java.lang.NullPointerException
11:32:32,734 ERROR [STDERR] java.lang.NullPointerException
11:32:32,735 ERROR [STDERR] at org.jboss.ejb3.entity.ExtendedEntityManager.getPersistenceContext(ExtendedEntityManager.java:59)
11:32:32,736 ERROR [STDERR] at org.jboss.ejb3.entity.ExtendedEntityManager.createQuery(ExtendedEntityManager.java:129)
11:32:32,736 ERROR [STDERR] at org.jboss.seam.example.registration.AnswersBean$AnswerConverter.getAsObject(AnswersBean.java:104)
11:32:32,736 ERROR [STDERR] at org.apache.myfaces.renderkit.RendererUtils.getConvertedUIOutputValue(RendererUtils.java:658)
11:32:32,736 ERROR [STDERR] at org.apache.myfaces.renderkit.html.HtmlRadioRendererBase.getConvertedValue(HtmlRadioRendererBase.java:288)
11:32:32,737 ERROR [STDERR] at javax.faces.component.UIInput.getConvertedValue(UIInput.java:289)
11:32:32,737 ERROR [STDERR] at javax.faces.component.UIInput.validate(UIInput.java:265)
11:32:32,737 ERROR [STDERR] at javax.faces.component.UIInput.processValidators(UIInput.java:144)
11:32:32,738 ERROR [STDERR] at javax.faces.component.UIData.process(UIData.java:514)
11:32:32,738 ERROR [STDERR] at javax.faces.component.UIData.processColumnChildren(UIData.java:498)
11:32:32,738 ERROR [STDERR] at javax.faces.component.UIData.processValidators(UIData.java:403)
11:32:32,738 ERROR [STDERR] at javax.faces.component.UIForm.processValidators(UIForm.java:68)
11:32:32,739 ERROR [STDERR] at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:417)
11:32:32,739 ERROR [STDERR] at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:142)
11:32:32,739 ERROR [STDERR] at org.apache.myfaces.lifecycle.LifecycleImpl.processValidations(LifecycleImpl.java:240)
11:32:32,740 ERROR [STDERR] at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:76)
11:32:32,740 ERROR [STDERR] at javax.faces.webapp.FacesServlet.service(FacesServlet.java:106)
11:32:32,740 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
11:32:32,740 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
11:32:32,741 ERROR [STDERR] at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
11:32:32,741 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
11:32:32,741 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
11:32:32,742 ERROR [STDERR] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
11:32:32,742 ERROR [STDERR] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
11:32:32,742 ERROR [STDERR] at org.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:54)
11:32:32,743 ERROR [STDERR] at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:174)
11:32:32,743 ERROR [STDERR] at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
11:32:32,743 ERROR [STDERR] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
11:32:32,744 ERROR [STDERR] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
11:32:32,744 ERROR [STDERR] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
11:32:32,744 ERROR [STDERR] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
11:32:32,745 ERROR [STDERR] at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
11:32:32,745 ERROR [STDERR] at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
11:32:32,746 ERROR [STDERR] at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
11:32:32,746 ERROR [STDERR] at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
11:32:32,746 ERROR [STDERR] at java.lang.Thread.run(Unknown Source)

While the page that I'm trying to render contains:

<h:dataTable var="question" value="#{questions}" rendered="#{questions.rowCount>0}">
<h:column>
 <f:facet name="Question">
 <h:outputText value="Question text"/>
 </f:facet>
 <h:outputText value="#{question.text}" />
 </h:column>
 <h:column>
 <f:facet name="Answer">
 <h:outputText value="Answers"/>
 </f:facet>
 <h:outputText value="#{question.selectedAnswer}"/>
 </h:column>

 </h:dataTable>

Initially I had no EXTENDED PersistenceContextType but I had a similar NullPointerException in ManagedEntityManagerFactory.getNonTxEntityManager()

Does this have something to do with that on the second page there's no reference to ansbean?

Thanks in advance for any hint. I have to say that the seam model is somehow unclear to me yet...

[gavin.king]

Looks like a bug in JBoss EJB3. I think I have seen someone else report this. Create a simple test case and submit it to EJB3 JIRA.

What happens if you use:

@PersistenceContext
 EntityManager em;

And remove (type=EXTENDED)?

[gavin.king]

Also, please notice that APPLICATION-scoped stateful session beans are problematic. SFSBs do not support concurrent access. It is better to use a JavaBean component if you need to cache stuff in application scope.

[villo]

What happens if you use:

Code:

@PersistenceContext
EntityManager em;



And remove (type=EXTENDED)?

It fails similarly, the same NullPointerException

at org.jboss.ejb3.entity.ManagedEntityManagerFactory.getNonTxEntityManager(ManagedEntityManagerFactory.java:58)

Should I wrap a testcase including the seam components?

About the SFSB: I did it this way having looked at the CategoriesBean class in the dvd store example app...

Actually I did this since I hadn't managed to get the Converter working through faces-config.xml...Is this supposed to be so?

[gavin.king]

Should I wrap a testcase including the seam components?

Any *simple* EAR should be fine. But make sure you cut it down to just what is required to reproduce the problem. Thanks.

About the SFSB: I did it this way having looked at the CategoriesBean class in the dvd store example app...

Ah. I will fix the DVDStore example. Thanks.

Actually I did this since I hadn't managed to get the Converter working through faces-config.xml...Is this supposed to be so?

I don't understand.

[villo]

Quote:
Actually I did this since I hadn't managed to get the Converter working through faces-config.xml...Is this supposed to be so?


I don't understand.

I mean that I wasn't able to use the Converter by registering it with

<converter>
 <converter-for-class>org.jboss.seam.example.registration.Answer</converter-for-class>
 <converter-class>org.jboss.seam.example.registration.AnswerConverter</converter-class>
</converter>

So I had to specify the converter with the converter attribute

<h:selectOneMenu value="#{register.answer}" converter="#{ansbean.converter}">
...
</h:selectOneMenu>

And I don't understand why...