Java Reference
In-Depth Information
To make use of the alternative implementation, the alternative class must be specified within the beans.xml,
which can be changed at deployment time.
<beans ... >
<alternatives>
<class>org.javaee7.chapter07.EmployeeProcessorTestImpl</class>
</alternatives>
</beans>
■
In order to use the standard implementation rather than the alternative, simply comment out the
<alternatives>
elements along with all enclosing alternative class specifications.
Note
In CDI 1.1, the
@Priority
annotation can be used to indicate that an alternative is to be used for an entire
application. For instance, in the following code, the
EmployeeProcessorTestImpl
alternative contains a priority of
APPLICATION
:
@Alternative
@Priority(APPLICATION)
public class EmployeeProcessorTestImpl implements Hire {
...
}
For more information on alternatives, please see the online documentation in the Java EE 7 tutorial.
Deprecations
The
@New
annotation was previously used to allow the application to obtain a new instance of a bean, which is not
bound to the declared scope but has had dependency injection performed. The CDI 1.1 update deprecates the use
of the
@New
qualifier and injects
@Dependent
-scoped beans instead. Let's take a look at how the
@New
qualifier used to
work, and then you will learn how to utilize the
@Dependent
scope instead.
In the following example, the
@New
qualifier is specified at an injection point to obtain a new instance of a bean
that is not bound to the declared scope.
@Produces @ConversationScoped
Order getOrder(@New(Order.class) Order order){
...
}
This same type of result can be achieved by declaring a bean as
@Dependent
. When a bean is declared to have
@Dependent
scope, the following are all true:
It is not possible to share an injected instance of that bean between any other injection points.
•
•
Any instance of the bean that has been injected into an object that is created by the container
is bound to the same life cycle as the newly created object.
•
At most one instance of the bean is instantiated if referred to within JSF or JSP EL.
