How to replace @ManagedBean / @ViewScope by CDI in JSF 2.0/2.1
I'm currently evaluating Java EE 6 / JSF 2.1 with RichFaces.
A bean which is declared as
@ManagedBean
@ViewScoped
- Gets an ID set (to prepare e.g. a delete operation).
- Via JSF a confirmation popup is displayed.
- If the user confirms, the delete method is invoked and removes the row for which the ID was stored in step 1.
Since CDI beans don't have a ViewScope I tried to declare the bean as:
@Named
@ConversationScoped
Now the processing fails in step 3. because the value that was set in step 1 (checked that) is no longer available.
Do I have to use Conversation.begin() and Conversation.end() methods?
If so, where would be good place to invoke them?
Answer
If you can upgrade to JSF 2.2, immediately do it. It offers a native @ViewScoped annotation for CDI.
import javax.faces.view.ViewScoped;
import javax.inject.Named;
@Named
@ViewScoped
public class Bean implements Serializable {
// ...
}
Alternatively, install OmniFaces which brings its own CDI compatible @ViewScoped, including a working @PreDestroy (which is broken on JSF @ViewScoped).
import javax.inject.Named;
import org.omnifaces.cdi.ViewScoped;
@Named
@ViewScoped
public class Bean implements Serializable {
// ...
}
Another alternative is to install MyFaces CODI which transparently bridges JSF 2.0/2.1 @ViewScoped to CDI. This only adds an autogenerated request parameter to the URL (like @ConversationScoped would do).
import javax.faces.bean.ViewScoped;
import javax.inject.Named;
@Named
@ViewScoped
public class Bean implements Serializable {
// ...
}
If you really need to use @ConversationScoped, then you indeed need to maunally begin and end it. You need to @Inject a Conversation and invoke begin() in the @PostConstruct and end() in the latest step of the conversation, usually an action method which redirects to a new view.
import javax.enterprise.context.Conversation;
import javax.enterprise.context.ConversationScoped;
import javax.inject.Named;
@Named
@ConversationScoped
public class Bean implements Serializable {
@Inject
private Conversation conversation;
// ...
@PostConstruct
public void init() {
conversation.begin();
}
public String submit() {
// ...
conversation.end();
return "some.xhtml?faces-redirect=true";
}
}