Intro

The Intro page provides an overview and describes the motivation for the features described below.

Dependencies

The page CODI Modules provides an overview about CODI modules and how to add them to your project.

For using the features described in this page, you have to add the core, the message module and the JSF module for the JSF version you are using.

Scopes

Conversation Scope

First of all it's important to mention that CODI starts (grouped) conversations automatically as soon as you access conversation scoped beans. Furthermore, the invocation of Conversation#end* leads to an immediate termination of the conversation.

import org.apache.myfaces.extensions.cdi.core.api.scope.conversation.ConversationGroup;

@ConversationScoped
public class DemoBean1 implements Serializable
{
  //...
}

... leads to a conversation which contains just one bean with the group DemoBean1.

Grouped Conversations

(In case of CDI std. conversations there is just one big conversation which contains all conversation scoped beans.)
The grouped conversations provided by CODI are completely different. By default every conversation scoped bean exists in an "isolated" conversation. That means there are several parallel conversations within the same window.

Example:

@ConversationScoped
public class DemoBean2 implements Serializable
{
  //...
}

@ConversationScoped
public class DemoBean3 implements Serializable
{
  //...
}

... leads to two independent conversations in the same window (context).
If you end the conversation of DemoBean2, the conversation of DemoBean3 is still active.

If you have an use-case (e.g. a wizard) which uses multiple beans which are linked together very tightly, you can create a type-safe conversation group.

interface Wizard1 {}

@ConversationScoped
@ConversationGroup(Wizard1.class)
public class DemoBean4 implements Serializable
{
  //...
}

@ConversationScoped
@ConversationGroup(Wizard1.class)
public class DemoBean5 implements Serializable
{
  //...
}

You can use @ConversationGroup to tell CODI that there is a logical group of beans. Technically @ConversationGroup is just a CDI qualifier. Internally CODI uses this information to identify a conversation. In the previous example both beans exist in the same conversation (group). If you terminate the conversation group, both beans will be destroyed. If you don't use @ConversationGroup explicitly, CODI uses the class of the bean as conversation group.

//...
public class CustomBean1
{
  @Inject
  @ConversationGroup(Group1.class)
  private CustomBean2 demoBean;

  @Inject
  @ConversationGroup(Group2.class)
  private CustomBean2 demoBean;
}

Since @ConversationGroup is a std. CDI qualifier you have to use it at the injection point. You have to do that esp. because it's possible to create beans of the same type which exist in different groups (e.g. via producer methods).

Example:

interface Group1 {}
interface Group2 {}

public class CustomBean2
{
  @Produces
  @ConversationScoped
  @ConversationGroup(Group1.class)
  public CustomBean2 createInstanceForGroup1()
  {
    return new CustomBean2();
  }

  @Produces
  @ConversationScoped
  @ConversationGroup(Group2.class)
  public CustomBean2 createInstanceForGroup2()
  {
    return new CustomBean2();
  }
}

Terminating Conversations

You can inject the conversation via @Inject and use it to terminate the conversation immediately (see *) or you inject the current WindowContext which can be used to terminate a given conversation group.

import org.apache.myfaces.extensions.cdi.core.api.scope.conversation.ConversationScoped;
import org.apache.myfaces.extensions.cdi.core.api.scope.conversation.Conversation;

@ConversationScoped
public class DemoBean6 implements Serializable
{
  @Inject
  private Conversation conversation; //injects the conversation of DemoBean6 (!= conversation of DemoBean7)

  //...

  public void finish()
  {
    this.conversation.end();
  }
}

@ConversationScoped
public class DemoBean7 implements Serializable
{
  @Inject
  private Conversation conversation; //injects the conversation of DemoBean7 (!= conversation of DemoBean6)

  //...

  public void finish()
  {
    this.conversation.end();
  }
}

interface Wizard2 {}

@ConversationScoped
@ConversationGroup(Wizard2.class)
public class DemoBean8 implements Serializable
{
  @Inject
  private Conversation conversation; //injects the conversation of Wizard2 (contains DemoBean8 and DemoBean9)

  //...

  public void finish()
  {
    this.conversation.end();
  }
}

@ConversationScoped
@ConversationGroup(Wizard2.class)
public class DemoBean9 implements Serializable
{
  @Inject
  private Conversation conversation; //injects the conversation of Wizard2 (contains DemoBean8 and DemoBean9)

  //...

  public void finish()
  {
    this.conversation.end();
  }
}

//...
public class DemoBean10 implements Serializable
{
  @Inject
  private WindowContext windowContext; //injects the whole window context (of the current window)

  //...

  public void finish()
  {
    this.windowContext.endConversationGroup(Wizard2.class);  //ends the conversation of group Wizard2.class
  }
}

//...
public class DemoBean11 implements Serializable
{
  @Inject
  private WindowContext windowContext;

  //...

  public void finish()
  {
    this.windowContext.endConversations();  //ends all existing conversations within the current window (context)
  }
}

Restarting conversations

Instead of destroying the whole conversation the conversation stays active and only the scoped instances are destroyed. (The conversation will be marked as accessed.) As soon as an instance of a bean is requested, the instance will be created based on the original bean descriptor. This approach allows a better performance, if the conversation is needed immediately (e.g. if you know in your action method that the next page will/might use the same conversation again).

@ConversationScoped
public class DemoBean12 implements Serializable
{
  @Inject
  private Conversation conversation;

  //...

  public void finish()
  {
    this.conversation.restart();
  }
}

View Access Scope

In case of conversations you have to un-scope beans manually (or they we be terminated automatically after a timeout). However, sometimes you need beans with a lifetime which is as long as needed and as short as possible - which are terminated automatically (as soon as possible). In such an use-case you can use this scope. The simple rule is, as long as the bean is referenced by a page - the bean will be available for the next page (if it's used again the bean will be forwarded again). It is important that it's based on the view-id of a page (it isn't based on the request) so e.g. Ajax requests don't trigger a cleanup if the request doesn't access all view-access scoped beans of the page. That's also the reason for the name @*View*AccessScoped.

@ViewAccessScoped
public class WizardBean implements Serializable
{
  //...
}

The usage of this scope is very similar to normal conversations. Only the cleanup strategy is different and the concept itself doesn't need/support the usage of @ConversationGroup.

Window Scope

The usage of this scope is very similar to normal conversations. Only the cleanup strategy is different and the concept itself doesn't need/support the usage of @ConversationGroup.

@WindowScoped
public class PreferencesBean implements Serializable
{
  //...
}

Terminating the Window Scope/ window scoped Beans

Since WindowContext#endConversations doesn't affect window scoped beans we need a special API for terminating all window scoped beans.
If you don't use qualifiers for your window scoped beans, you can just inject the conversation into a window scoped bean and invoke the methods discussed above. If you don't have this constellation, you can use the WindowContext to terminate the window scoped beans or the whole window context. If you terminate the whole window, you also destroy all conversation and view-access scoped beans automatically.

//...
public class CustomWindowControllerBean1
{
  @Inject
  private WindowContext windowContext;

  //...

  public void closeWindow()
  {
    this.windowContext.end();
  }
}

//...
public class CustomWindowControllerBean2
{
  @Inject
  private WindowContext windowContext;

  //...

  public void finish()
  {
    this.windowContext.endConversationGroup(WindowScoped.class);
  }
}

View Scope (JSF 2+ only)

JSF 2.0 introduced the View Scope. CODI allows to use all the CDI mechanisms in beans annotated with javax.faces.bean.ViewScoped.

Flash Scope

CODI provides a fine grained conversation scope with multiple parallel and isolated/independent conversations within a single window as well as a view-access scope (see above). So we (currently) don't think that we need a flash scope. Please contact us, if you find an use-case which needs the flash scope and you can't use the other CODI scopes. Other portable extensions (like Seam 3 btw. Seam-Faces) just provide this scope because they don't have such fine grained conversations.

Dependency Injection

CODI allows using @Inject within the following JSF (1.2 and 2.0) artifacts:

• Converter
• Validator
• PhaseListener

As soon as a converter or a validator is annotated with @Advanced it's possible to use @Inject.

Example for a validator:

@Advanced
//@FacesValidator("...") //in case of JSF 2.0
public class DependencyInjectionAwareValidator implements Validator
{
  @Inject
  private CustomValidationService customValidationService;

  public void validate(FacesContext facesContext, UIComponent uiComponent, Object value) throws ValidatorException
  {
    Violation violation = this.customValidationService.validate(value);
    //...
  }
}

Example for a converter:

@Advanced
//@FacesConverter("...") //in case of JSF 2.0
public class DependencyInjectionAwareConverter implements Converter
{
  @Inject
  private OrderService orderService;

  public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String value)
      throws ConverterException
  {
    if (value != null && value.length() > 0)
    {
      return this.orderService.loadByOrderNumber(value);
    }
    return null;
  }

  //...
}

Life-cycle Annotations

Phase-Listener Methods

As an alternative to a full phase-listener CODI allows to use observers as phase-listener methods.

Example:

protected void observePreRenderView(@Observes @BeforePhase(PhaseId.RENDER_RESPONSE) PhaseEvent phaseEvent)
{
  //...
}

If you would like to restrict the invocation to a specific view, it's possible to use the optional @View annotation.

@View(DemoPage.class)
public void observePostInvokeApplication(@Observes @AfterPhase(PhaseId.INVOKE_APPLICATION) PhaseEvent event)
{
  //...
}

For further details about DemoPage.class please have a look at the view-config section.

Phase-Listener

CODI provides an annotation for phase-listeners:

@JsfPhaseListener
public class DebugPhaseListener implements PhaseListener
{
  private static final Log LOG = LogFactory.getLog(DebugPhaseListener.class);

  private static final long serialVersionUID = -3128296286005877801L;

  public void beforePhase(PhaseEvent phaseEvent)
  {
      if(LOG.isDebugEnabled())
      {
        LOG.debug("before: " + phaseEvent.getPhaseId());
      }
  }

  public void afterPhase(PhaseEvent phaseEvent)
  {
    if(LOG.isDebugEnabled())
    {
      LOG.debug("after: " + phaseEvent.getPhaseId());
    }
  }

  public PhaseId getPhaseId()
  {
    return PhaseId.ANY_PHASE;
  }
}

If you have to specify the order of phase-listeners you can us the optional @InvocationOrder annotation.
In combination with @Advanced it's possible to use dependency injection.

Example:

@Advanced
@JsfPhaseListener
@InvocationOrder(1) //optional
public class DebugPhaseListener implements PhaseListener
{
  @Inject
  private DebugService debugService;

  public void beforePhase(PhaseEvent phaseEvent)
  {
    this.debugService.log(phaseEvent);
  }

  public void afterPhase(PhaseEvent phaseEvent)
  {
    this.debugService.log(phaseEvent);
  }

  public PhaseId getPhaseId()
  {
    return PhaseId.ANY_PHASE;
  }
}

Faces-Request-Listener

Sometimes it's essential to perform logic directly after the FacesContext started and/or directly before the FacesContext gets destroyed. In such a case CODI provides the annotations @BeforeFacesRequest and @AfterFacesRequest.

Example:

protected void initFacesRequest(@Observes @BeforeFacesRequest FacesContext facesContext)
{
  //...
}

Producers

CODI offers a bunch of producers for JSF artifacts.

Example:

@Inject
private FacesContext facesContext;

Type-safe View Config

In some projects users are using enums which allow e.g. a type-safe navigation. CODI provides a mechanism which goes beyond that. You can use classes which hosts a bunch meta-data. One use-case is to use these special classes for type-safe navigation. Beyond that CODI allows to provide further meta-data e.g. page-beans which are loaded before the rendering process starts, type-safe security and it's planned to add further features to this mechanism.

The following example shows a simple view-config.

@Page
public final class Home implements ViewConfig
{
}

This mechanism works due to the naming convention. Instead of the convention it's possible to specify the name of the page manually. This feature is described at the end of this section.

If you would like to group pages (you will learn some reasons for that later on), you can nest the classes.

@Page(basePath = "")
public abstract class Wizard implements ViewConfig
{
    @Page
    public final class Page1 extends Wizard
    {
    }

    @Page
    public final class Page2 extends Wizard
    {
    }
}

Such a grouping allows to reduce the number of class files in your workspace. Furthermore modern IDEs allow to show the logical hierarchy out-of-the-box (in Intellij it's called "Type Hierarchy").

Organizing your pages

View configs allow to reflect your folder structure in the meta-classes.

@Page
public abstract class UseCase1 implements ViewConfig
{
    @Page
    public final class Step1 extends Wizard
    {
    }

    @Page
    public final class Step2 extends Wizard
    {
    }
}

... leads to the following view-ids: /useCase1/step1.xhtml and /useCase1/step2.xhtml.
That means - if you rename the folder useCase1, you just have to rename a single class and everything is in sync again.

Type-safe Navigation

In the previous section you have learned some details about the view-config mechanism provided by CODI. You can use these meta-classes for the navigation.

Example:

public Class<? extends ViewConfig> navigateToHomeScreen()
{
    return Home.class;
}

Type-safe Security

@Page
@Secured(OrderVoter.class)
public final class OrderWizard implements ViewConfig
{
} 

@ApplicationScoped
public class OrderVoter extends AbstractAccessDecisionVoter
{
    @Inject
    private UserService userService;

    @Inject
    private User currentUser;

    public void checkPermission(InvocationContext invocationContext, Set<SecurityViolation> violations)
    {
        if(!this.loginService.isActiveUser(this.currentUser))
        {
            violations.add(newSecurityViolation("{inactive_user_violation}"));
        }
    }
}

The message-key of the previous example will be passed to the MessageContext with the Jsf qualifier. You can also use a hardcoded inline message. If you would like to use a different MessageContext you can just inject it (see the following example).

@ApplicationScoped
public class OrderVoter extends AbstractAccessDecisionVoter
{
    @Inject
    private UserService userService;

    @Inject
    private User currentUser;

    @Inject
    @Custom
    private MessageContext messageContext;

    public void checkPermission(InvocationContext invocationContext, Set<SecurityViolation> violations)
    {
        if(!this.loginService.isActiveUser(this.currentUser))
        {
            String reason = this.messageContext.message().text("{inactive_user_violation}").toText();
            violations.add(newSecurityViolation(reason));
        }
    }
}

Error pages

The following example shows how to create a default error page. It's just allowed to provide one default error page per application.
Instead of implementing ViewConfig it's required to implement the DefaultErrorView interface.

@Page
public final class Login implements DefaultErrorView
{
}

If there isn't an error page, CODI will throw an AccessDeniedException.