javax.enterprise.context

Annotation Type Dependent

@Target(value={METHOD,TYPE,FIELD})
@Retention(value=RUNTIME)
@Documented
@Scope
@Inherited
public @interface Dependent

Specifies that a bean belongs to the dependent pseudo-scope.

Beans declared with scope @Dependent behave differently to beans with other built-in scope types. When a bean is declared to have scope @Dependent:

• No injected instance of the bean is ever shared between multiple injection points.
• Any instance of the bean injected into an object that is being created by the container is bound to the lifecycle of the newly created object.
• When a Unified EL expression in a JSF or JSP page that refers to the bean by its EL name is evaluated, at most one instance of the bean is instantiated. This instance exists to service just a single evaluation of the EL expression. It is reused if the bean EL name appears multiple times in the EL expression, but is never reused when the EL expression is evaluated again, or when another EL expression is evaluated.
• Any instance of the bean that receives a producer method, producer field, disposer method or observer method invocation exists to service that invocation only.
• Any instance of the bean injected into method parameters of a disposer method or observer method exists to service the method invocation only.

Every invocation of the Context.get(Contextual, CreationalContext) operation of the context object for the @Dependent scope returns a new instance of the given bean.

Every invocation of the Context.get(Contextual) operation of the context object for the @Dependent scope returns a null value.

The @Dependent scope is always active.

Many instances of beans with scope @Dependent belong to some other bean or Java EE component class instance and are called dependent objects.

• Instances of decorators and interceptors are dependent objects of the bean instance they decorate.
• An instance of a bean with scope @Dependent injected into a field, bean constructor or initializer method is a dependent object of the bean or Java EE component class instance into which it was injected.
• An instance of a bean with scope @Dependent injected into a producer method is a dependent object of the producer method bean instance that is being produced.
• An instance of a bean with scope @Dependent obtained by direct invocation of an Instance is a dependent object of the instance of Instance.

When the container destroys an instance of a bean or of any Java EE component class supporting injection, the container destroys all its dependent objects, after the @PreDestroy callback completes and after the servlet destroy() method is called.

Author:

Gavin King, Pete Muir