/*
* Copyright (C) 2010 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package javax.enterprise.context;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import javax.inject.Scope;
import java.lang.annotation.Documented;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* <p>Specifies that a bean belongs to the dependent pseudo-scope.</p>
*
* <p>Beans declared with scope <tt>@Dependent</tt> behave differently
* to beans with other built-in scope types. When a bean is declared
* to have scope <tt>@Dependent</tt>:</p>
*
* <ul>
* <li>No injected instance of the bean is ever shared between
* multiple injection points.</li>
* <li>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.</li>
* <li>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.</li>
* <li>Any instance of the bean that receives a producer method,
* producer field, disposer method or observer method invocation
* exists to service that invocation only.</li>
* <li>Any instance of the bean injected into method parameters of a
* disposer method or observer method exists to service the method
* invocation only.</li>
* </ul>
*
* <p>Every invocation of the
* {@link javax.enterprise.context.spi.Context#get(Contextual, CreationalContext)}
* operation of the context object for the <tt>@Dependent</tt> scope
* returns a new instance of the given bean.</p>
*
* <p>Every invocation of the
* {@link javax.enterprise.context.spi.Context#get(Contextual)}
* operation of the context object for the <tt>@Dependent</tt> scope
* returns a null value.</p>
*
* <p>The <tt>@Dependent</tt> scope is always active.</p>
*
* <p>Many instances of beans with scope <tt>@Dependent</tt> belong
* to some other bean or Java EE component class instance and are
* called dependent objects.</p>
*
* <ul>
* <li>Instances of decorators and interceptors are dependent
* objects of the bean instance they decorate.</li>
* <li>An instance of a bean with scope <tt>@Dependent</tt> 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.</li>
* <li>An instance of a bean with scope <tt>@Dependent</tt> injected
* into a producer method is a dependent object of the producer method
* bean instance that is being produced.</li>
* <li>An instance of a bean with scope <tt>@Dependent</tt> obtained by
* direct invocation of an {@link javax.enterprise.inject.Instance} is
* a dependent object of the instance of
* {@link javax.enterprise.inject.Instance}.</li>
* </ul>
*
* <p>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 <tt>@PreDestroy</tt> callback completes
* and after the servlet <tt>destroy()</tt> method is called.</p>
*
* @author Gavin King
* @author Pete Muir
*/
@Target( { METHOD, TYPE, FIELD })
@Retention(RUNTIME)
@Documented
@Scope
@Inherited
public @interface Dependent
{
}