[jboss-user] [JBoss Seam] - DataInputSelection has problem with injection

Mon Oct 15 03:48:05 EDT 2007

This is my second topic about the same problem, but due to the amount of new topics on the forum, it`s kinda necessary.

I`ve written a simple controller using code snippet from the 1 chapter of Seam tutorial.

  | @Stateful
  | @Name("TestController")
  | public class TestControllerBean implements Serializable, TestController {
  |     
  |     @Logger
  |     private Log log;
  |     
  |     @In
  |     private EntityManager entityManager;
  |     
  |     @DataModel
  |     private List<QuestionCategory> questionCategoryList;
  |     
  |     @DataModelSelection
  |     @Out(required=false)
  |     private QuestionCategory questionCategory;
  |     
  |     /** Creates a new instance of TestControllerBean */
  |     public TestControllerBean() {
  |     }
  | 
  |     public void remove() {
  |         questionCategoryList.remove(questionCategory);
  |         entityManager.remove(questionCategory);
  |         questionCategory = null;
  |     }
  |     
  |     @Factory(value="questionCategoryList")
  |     public void showAll() {
  |         questionCategoryList = entityManager.createQuery("from QuestionCategory qc").getResultList();
  |     }
  |     
  |     @Remove @Destroy
  |     public void destroy() {}
  |     
  | }
  | 

And the test.xhtml

  | <html xmlns="http://www.w3.org/1999/xhtml"
  |       xmlns:ui="http://java.sun.com/jsf/facelets"
  |       xmlns:h="http://java.sun.com/jsf/html"
  |       xmlns:f="http://java.sun.com/jsf/core"
  |       xmlns:s="http://jboss.com/products/seam/taglib">
  |     <body>
  |         
  |         <h:form>
  |             <h:outputText value="categoryList rowCount is null" rendered="#{questionCategoryList.rowCount == null}"/><br/>
  |             <h:outputText value="categoryList rowCount = 0" rendered="#{questionCategoryList.rowCount == 0}"/><br/>
  |             <h:outputText value="Available categoryList: " rendered="#{questionCategoryList.rowCount > 0}"/><br/>
  |             <h:dataTable var="cat" value="#{questionCategoryList}">
  |                 <h:column>
  |                     <h:outputText value="[ #{cat.categoryName} ]"/>
  |                 </h:column>
  |                 <h:column>
  |                     <h:outputText value=" - [ #{cat.created} ]"><f:convertDateTime pattern="dd-MMM-yyyy H:mm"/></h:outputText>
  |                 </h:column>
  |                 <h:column>
  |                     <s:link value="remove" action="#{TestController.remove}"/>
  |                 </h:column>
  |             </h:dataTable>
  |         </h:form>
  |         
  |         <ui:debug hotkey="d"/>
  |         
  |     </body>
  | </html>
  | 

It works fine when I want to render list of questionCategories but when i hit "remove" link i get NullPointerException indicating, as far as i think, that questionCategory isn`t injected to the stateful bean.

The only difference between this code and the tutorial is that in my code i didn`t use @Scope(SESSION) but I don`t think that this could be a problem.

Any ideas about solving my problem ????

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