javax.enterprise.event.Observes Maven / Gradle / Ivy
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* full listing of individual contributors.
*
* 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.event;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* Identifies the event parameter of an observer method. May be applied to
* a parameter of a method of a bean class or
* {@linkplain javax.enterprise.inject.spi.Extension extension}.
*
*
* public void afterLogin(@Observes LoggedInEvent event) { ... }
*
*
* An observer method is a non-abstract method of a managed bean class or
* session bean class (or of an extension). An observer method may be either
* static or non-static. If the bean is a session bean, the observer method
* must be either a business method of the EJB or a static method of the bean
* class.
*
* Each observer method must have exactly one event parameter, of the same
* type as the event type it observes. Event qualifiers may be declared
* by annotating the event parameter. When searching for observer methods for
* an event, the container considers the type and qualifiers of the event
* parameter.
*
* If the event parameter does not explicitly declare any qualifier, the
* observer method observes events with no qualifier.
*
* The event parameter type may contain a type variable or wildcard.
*
* In addition to the event parameter, observer methods may declare
* additional parameters, which may declare qualifiers. These additional
* parameters are injection points.
*
*
* public void afterLogin(@Observes LoggedInEvent event, @Manager User user, Logger log) { ... }
*
*
* A bean (or extension) may declare multiple observer methods.
*
* Observer methods are inherited by bean subclasses.
*
* Interceptors and decorators may not declare observer
* methods.
*
* @author Gavin King
* @author Pete Muir
* @author David Allen
*/
@Target(PARAMETER)
@Retention(RUNTIME)
@Documented
public @interface Observes
{
/**
* Specifies
* {@linkplain javax.enterprise.event.Reception under what conditions the
* observer method is notified}.
*
* By default, the observer method is notified even if no instance of
* the bean that defines the observer method already exists in the current
* context.
*/
public Reception notifyObserver() default Reception.ALWAYS;
/**
* Specifies
* {@linkplain javax.enterprise.event.Reception at what time the observer
* method is notified}.
*
* By default, the observer method is notified when the event is fired.
*/
public TransactionPhase during() default TransactionPhase.IN_PROGRESS;
}