jakarta.enterprise.event.ObservesAsync Maven / Gradle / Ivy
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* JBoss, Home of Professional Open Source
* Copyright 2015, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* 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 jakarta.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 asynchronous observer method. May be applied to a parameter of a method of a bean class
*
*
*
* public void afterLogin(@ObservesAsync 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(@ObservesAsync 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 ObservesAsync {
/**
*
* Specifies {@linkplain 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.
*
* @return conditional observer type
*/
public Reception notifyObserver() default Reception.ALWAYS;
}