Injecting a view scoped bean into another view scoped bean
jsf, jsf-2.2, managed-bean
Solution
Even it's technically possible to do that (JSF allows you to inject beans which are at the same or wider scope) I don't see the point of doing that with `@ViewScoped` beans. From my point of view, a well designed JSF web application should have a single `@ViewScoped` bean tied to each specific view. Then, how to solve your issue? You can do it in two ways:
- If `SharableManagedBean` is a utility bean which contain static methods which are not tied to JSF, just define this class as `abstract` and statically invoke its methods everytime you need.
- If `SharableManagedBean` itself has to be a managed bean which access the `FacesContext` and has common code that is shared along all the view beans, just create an `abstract` class and make your `@ViewScoped` beans extend it.
For your last question (`SharableManagedBean` being `@RequestScoped`), JSF doesn't allow you doing that. You'll get an exception because of trying to inject a narrower scoped managed bean.
According to the Oracle docs:
Another important point about managed beans referencing each other is that a managed bean can only refer to other beans provide their scope is equal or has a longer lifespan than the calling object.
Update
If using CDI, it's possible to inject a `@RequestScoped` bean into a `@ViewScoped` one too, using the Proxy pattern. Have it a look.
Problem
A view scoped bean remains alive as long as the user interacts with the same view (or until it is navigated to a different view). Suppose a view scoped managed bean is injected into another view scoped bean like so, ``` @ManagedBean @ViewScoped public final class SharableManagedBean implements Serializable { private static final long serialVersionUID = 1L; @EJB private SharableBean sharableService; //...Do something. } @ManagedBean @ViewScoped public final class TestManagedBean implements Serializable { private static final long serialVersionUID = 1L; @EJB private TestBean testBean; @ManagedProperty(value="#{sharableManagedBean}") private SharableManagedBean sharableManagedBean ; //... Do something with the injected bean. } ``` In this case, is it necessary for the `SharableManagedBean` to have a view scoped bean? What happens, if it is a request scoped bean (`SharableManagedBean`)? Is it initialized only once, when `TestManagedBean` comes into picture and destroyed, when `TestManagedBean` is destroyed?