Intro/Motivation

MyFaces CODI provides powerful scopes for JSF applications. The inspiration for most parts came from MyFaces Orchestra. If you already know MyFaces Orchestra you will be able to use the scopes provided by MyFaces CODI easily. Also the migration of existing applications shouldn't be that hard.

For users who aren't familiar with the conversation concepts provided by MyFaces Orchestra:
Orchestra allows to group beans within a (named) conversation. Furthermore, it's possible to use beans with different (conversation-) lifecycles in the same page. (Usually there isn't one big conversation - like the std. CDI conversation which is more like a bit smarter session for a window/tab.) Conversations are bound to a window/tab of a browser. That means you automatically get new conversations, if you open the application in a new tab/window. Conversations are started automatically as soon as a conversation scoped bean is used. A conversation ends based on a timeout (in case of the access scope - a conversation ends as soon as it wasn't used by a page). Furthermore, it's possible to end (or restart) conversations manually. That means via an API call it's possible to end a conversation immediately. The next access leads to a new conversation. If the whole session gets destroyed, also all conversations will be destroyed automatically.

MyFaces CODI provides all these principles of MyFaces Orchestra in combination with typesafe improvements as well as the support of CDI mechanisms like qualifiers.

And why do we need new scopes? CDI already provides conversations. That's right and CDI is a great spec. and the EG did a nice job, however, (compared to the concepts of MyFaces Orchestra) CDI std. conversations are not that nice. So we saw the need to port a lot of the concepts provided by MyFaces Orchestra to CDI.

MyFaces CODI provides the following types of conversations:

• @ConversationScoped (!= the std. CDI scope)
• @WindowScoped
• @ViewAccessScoped

Simple Usage

Conversation Scoped

@ConversationScoped
public class DemoBean1 implements Serializable
{
  public String getWelcomeText()
  {
    return "Hello MyFaces CODI!";
  }
}

@Named
@ConversationScoped
public class DemoBean2 implements Serializable
{
  @Inject
  private DemoBean1 bean1;

  private String text;

  @PostConstruct
  protected void init()
  {
    text = this.bean1.getWelcomeText();
  }

  /*generated*/
  public String getText()
  {
    return text;
  }
}

#{demoBean2.text}
//e.g.: <h:outputText value="#{demoBean2.text}"/>

@ConversationScoped means you are using a bean with a timeout (default: 30 minutes). As soon as a bean gets accessed, the bean is touched which leads to a reset of the timeout.

@ConversationScoped
public class DemoBean3 implements Serializable
{
  @Inject
  private Conversation conversation;

  public void save()
  {
    //your custom logic
    //...

    this.conversation.end();

    //or use:
    //conversation.restart();
    //... if you know that you will need new instances of the same beans e.g. in the next view
    //#restart it's just a possible performance improvement
  }
}

Window Scope

The usage is exactly the same like @ConversationScoped . The only difference is that there is no timeout.
You can compare it to a session per window. However, as we will see later on it's possible to reset the window-context manually.

@WindowScoped
public class DemoBean4 implements Serializable
{
}

View-Access Scope

The usage is exactly the same like @ConversationScoped . The only difference is that there is no timeout. If you don't use @ViewAccessScoped beans within a view, they won't be available any longer. That means: They get cleaned up automatically, as soon as you don't use them.

@ViewAccessScoped
public class DemoBean5 implements Serializable
{
}

Conversation Groups

MyFaces Orchestra introduced conversation names to group conversation scoped beans. Instead of names MyFaces CODI provides a typesafe alternative: conversation groups. A conversation group is a marker class or interface. Behind the scenes @ConversationGroup is a CDI qualifier which is treated in a special way. If you don't define a special group the class of the bean is used as conversation group. That means: every conversation scoped bean belongs to an explicit or implicit conversation group.

@ConversationScoped
@ConversationGroup(ConversationGroup1.class)
public class DemoBean7 implements Serializable
{
    @Inject
    private Conversation conversation;

    public void save()
    {
      //...

      this.conversation.end();
    }
}

public interface ConversationGroup1
{
}

public class DemoBean7 implements Serializable
{
    @Produces
    @ConversationScoped
    @ConversationGroup(ConversationGroup1.class)
    public DemoBean6 createBeanForGroup1()
    {
        return new DemoBean6();
    }

    @Produces
    @ConversationScoped
    @ConversationGroup(ConversationGroup2.class)
    public DemoBean6 createBeanForGroup2()
    {
        return new DemoBean6();
    }
}

If you would like to end all conversations of an other conversation-group, you can use the WindowContext.

public class DemoBean8
{
    @Inject
    private WindowContext windowContext;

    public void save()
    {
      //...

      this.windowContext.endConversationGroup(ConversationGroup2.class);
    }
}