8 Replies Latest reply on Oct 16, 2007 4:09 AM by w17chm4n

DataModel and DataModelSelection question

w17chm4n Oct 11, 2007 11:18 AM

First of all, the code..

@Stateless
@Name("QuestionCategoryController")
public class QuestionCategoryControllerBean implements QuestionCategoryController {

 @Logger
 private Log log;

 @In(create = true)
 private QuestionCategoryManager questionCategoryManager;

 @In(required = false)
 private QuestionCategory questionCategory;

 @DataModel(value = "categories")
 private List<QuestionCategory> categoryList;

 @DataModelSelection(value = "categories")
 private List<Question> questionList;

 public void addCategory() {
 questionCategory.setCreated(new Date());
 questionCategoryManager.addCategory(this.questionCategory);
 }

 public void removeCategory(QuestionCategory questionCategory) { //todo
 log.info("Trying to remove #{questionCategory.categoryName}");
 if(questionCategory == null) {
 log.error("questionCategory is NULL !");
 } else {
 questionCategoryManager.removeCategory(questionCategory);
 }
 }

 @Factory("categories")
 public void getAllQuestionsCategories() {
 setCategoryList(questionCategoryManager.getAllQuestionCategories());
 }

 public List<QuestionCategory> getCategoryList() {
 return categoryList;
 }

 public void setCategoryList(List<QuestionCategory> categoryList) {
 this.categoryList = categoryList;
 }

 public List<Question> getQuestionList() {
 return questionList;
 }

 public void setQuestionList(List<Question> questionList) {
 this.questionList = questionList;
 }

}

and

<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:inputText value="#{questionCategory.categoryName}" required="true"/>
 <h:commandButton type="submit" value="Add new category" action="#{QuestionCategoryController.addCategory}"></h:commandButton><br/>
 <h:outputText value="Categories rowCount is null" rendered="#{categories.rowCount == null}"/><br/>
 <h:outputText value="Categories rowCount = 0" rendered="#{categories.rowCount == 0}"/><br/>
 <h:outputText value="Available categories: " rendered="#{categories.rowCount > 0}"/><br/>
 <h:dataTable var="cat" value="#{categories}">
 <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="#{QuestionCategoryController.removeCategory(cat)}"/>
 </h:column>
 </h:dataTable>
 </h:form>

 <ui:debug hotkey="d"/>

 </body>
</html>

Whats the problem is that QuestionCategoryController.removeCategory(cat) doesn`t work. I know it`s something about the annotations but I can`t find any answer.

As this controller should be used for adding new QuestionCategory, returning the existing categories and remove them i`ve also tried sth like that:

@Stateless
@Name("QuestionCategoryController")
public class QuestionCategoryControllerBean implements QuestionCategoryController {

 @Logger
 private Log log;

 @In(create = true)
 private QuestionCategoryManager questionCategoryManager;

 @DataModelSelection(value = "categories") @In(required = false) @Out(required = false)
 private QuestionCategory questionCategory;

 @DataModel(value = "categories")
 private List<QuestionCategory> categoryList;

 public void addCategory() {
 questionCategory.setCreated(new Date());
 questionCategoryManager.addCategory(this.questionCategory);
 }

 public void removeCategory(QuestionCategory questionCategory) { //todo
 log.info("Trying to remove #{questionCategory.categoryName}");
 if(questionCategory == null) {
 log.error("questionCategory is NULL !");
 } else {
 questionCategoryManager.removeCategory(questionCategory);
 }
 }

 @Factory("categories")
 public void getAllQuestionsCategories() {
 setCategoryList(questionCategoryManager.getAllQuestionCategories());
 }

 public List<QuestionCategory> getCategoryList() {
 return categoryList;
 }

 public void setCategoryList(List<QuestionCategory> categoryList) {
 this.categoryList = categoryList;
 }

}

Oh and the exception, I simply get an NullPointerException (or in logs "questionCategory is NULL !") so as I think, the QuestionCategory object isn`t injected into the removeQuestion method.

Any suggestions how to deal with this problem ?

1. Re: DataModel and DataModelSelection question

smithbstl Oct 11, 2007 11:26 AM (in response to w17chm4n)

You are using Stateless Beans, How do you expect state to be saved? Try using Stateful EJBs
Actions

2. Re: DataModel and DataModelSelection question

w17chm4n Oct 11, 2007 11:59 AM (in response to w17chm4n)

I`ve changed to stateful EJB but still it doesn`t inject the questionCategory.

@Stateful
@Name("QuestionCategoryController")
public class QuestionCategoryControllerBean implements QuestionCategoryController {

 @Logger
 private Log log;

 @In(create = true)
 private QuestionCategoryManager questionCategoryManager;

 @DataModelSelection
 @In(required = false)
 @Out(required = false)
 private QuestionCategory questionCategory;

 @DataModel
 private List<QuestionCategory> categoryList;

 @Out(required = false)
 private List<Question> questionList;

 public void addCategory() {
 questionCategory.setCreated(new Date());
 questionCategoryManager.addCategory(this.questionCategory);
 }

 public void removeCategory(QuestionCategory questionCategory) { //todo
 log.info("Trying to remove #{questionCategory.categoryName}");
 if(questionCategory == null) {
 log.fatal("questionCategory is NULL !");
 } else {
 questionCategoryManager.removeCategory(questionCategory);
 }
 }

 @Factory("categoryList")
 public void getAllQuestionsCategories() {
 setCategoryList(questionCategoryManager.getAllQuestionCategories());
 }

 public List<QuestionCategory> getCategoryList() {
 return categoryList;
 }

 public void setCategoryList(List<QuestionCategory> categoryList) {
 this.categoryList = categoryList;
 }

 public List<Question> getQuestionList() {
 return questionList;
 }

 public void setQuestionList(List<Question> questionList) {
 this.questionList = questionList;
 }

 @Destroy @Remove
 public void destroy() {}
}

3. Re: DataModel and DataModelSelection question

dhinojosa Oct 11, 2007 12:28 PM (in response to w17chm4n)

What was the result after you changed to stateful? Was it still:
questionCategory is NULL !
Actions
4. Re: DataModel and DataModelSelection question

smithbstl Oct 11, 2007 1:02 PM (in response to w17chm4n)

Try defining the DataModel in your DataModelSelection

@DataModelSelection("categoryList")

With only one DataModel in your bean, it should not be necessary but I always put it in to be safe.
Actions
5. Re: DataModel and DataModelSelection question

nickarls Oct 11, 2007 2:02 PM (in response to w17chm4n)

Try putting the bean and the datamodel to page scope and if it works, start narrowing down...
Actions
6. Re: DataModel and DataModelSelection question

w17chm4n Oct 12, 2007 7:31 AM (in response to w17chm4n)

First of all, thanks for all Yours replays !

"dhinojosa" wrote:
What was the result after you changed to stateful? Was it still:
questionCategory is NULL !

Yes, still it striked me with "questionCategory is NULL !

"smithbstl" wrote:
Try defining the DataModel in your DataModelSelection

@DataModelSelection("categoryList")

With only one DataModel in your bean, it should not be necessary but I always put it in to be safe.

I did that

Try putting the bean and the datamodel to page scope and if it works, start narrowing down...

and that, but still no success.

Any more ideas ???
Actions
7. Re: DataModel and DataModelSelection question

dhinojosa Oct 15, 2007 6:20 PM (in response to w17chm4n)

You don't have a scope on your "controller". If you do, sounds like you have some new changes to your code. Can you put em up here?
Actions

8. Re: DataModel and DataModelSelection question

w17chm4n Oct 16, 2007 4:09 AM (in response to w17chm4n)

I found the sollution.

@Stateful
@Scope(ScopeType.SESSION)
@Name("QuestionCategoryController")
public class QuestionCategoryControllerBean implements QuestionCategoryController {

 @Logger
 private Log log;

 @In(create = true)
 private QuestionCategoryManager questionCategoryManager;

 @DataModel
 private List<QuestionCategory> questionCategoryList;

 @DataModelSelection
 @In(required = false)
 private QuestionCategory questionCategory;

 public void addCategory() {
 questionCategoryManager.addCategory(questionCategory);
 getAllQuestionsCategories();
 }

 public void removeCategory() {
 questionCategoryList.remove(questionCategory);
 questionCategoryManager.removeCategory(questionCategory);
 questionCategory = null;
 getAllQuestionsCategories();
 }

 @Factory(value="questionCategoryList")
 public void getAllQuestionsCategories() {
 questionCategoryList = questionCategoryManager.getAllQuestionCategories();
 }

 @Remove @Destroy
 public void destroy() {}

}

@Stateful
@Scope(ScopeType.APPLICATION)
@Name("questionCategoryManager")
public class QuestionCategoryManagerBean implements QuestionCategoryManager {

 @Logger
 Log log;

 @PersistenceContext(type = PersistenceContextType.EXTENDED)
 private EntityManager entityManager;

 public void addCategory(QuestionCategory category) {
 category.setCreated(new Date());
 entityManager.persist(category);
 }

 public void removeCategory(QuestionCategory category) {
 entityManager.remove(category);
 }

 public List<QuestionCategory> getAllQuestionCategories() {
 return entityManager.createQuery("from QuestionCategory qc").getResultList();
 }

 @Destroy @Remove
 public void destroy() {
 }
}

@Entity
@Scope(ScopeType.EVENT)
@Name("questionCategory")
@Table(name="QuestionCategories")
public class QuestionCategory implements Serializable {

 @Id @GeneratedValue
 private Long id;

 @NotNull @Length(min=3, max=100)
 private String categoryName;

 @OneToMany
 private List<Question> questionList;

 @Temporal(value = TemporalType.TIMESTAMP)
 private Date created;

 /** Creates a new instance of QuestionCategory */
 public QuestionCategory() {
 this.questionList = new ArrayList<Question>();
 }

 public QuestionCategory(String categoryName) {
 this.categoryName = categoryName;
 this.questionList = new ArrayList<Question>();
 }

 public Long getId() {
 return id;
 }

 public void setId(Long id) {
 this.id = id;
 }

 public String getCategoryName() {
 return categoryName;
 }

 public void setCategoryName(String categoryName) {
 this.categoryName = categoryName;
 }

 public List<Question> getQuestionList() {
 return questionList;
 }

 public void setQuestionList(List<Question> questionList) {
 this.questionList = questionList;
 }

 public Date getCreated() {
 return created;
 }

 public void setCreated(Date created) {
 this.created = created;
 }
}

It was all about setting correct scopes ! Notice that entity bean has to have set Scope to event, without it, it won`t work.

Thx dhinojosa for all your support !

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