/*
* 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.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;
/**
* <p>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}.</p>
* <p/>
* <pre>
* public void afterLogin(@Observes LoggedInEvent event) { ... }
* </pre>
* <p/>
* <p>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.</p>
* <p/>
* <p>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.</p>
* <p/>
* <p>If the event parameter does not explicitly declare any qualifier, the
* observer method observes events with no qualifier.</p>
* <p/>
* <p>The event parameter type may contain a type variable or wildcard.</p>
* <p/>
* <p>In addition to the event parameter, observer methods may declare
* additional parameters, which may declare qualifiers. These additional
* parameters are injection points.</p>
* <p/>
* <pre>
* public void afterLogin(@Observes LoggedInEvent event, @Manager User user, Logger log) { ... }
* </pre>
* <p/>
* <p>A bean (or extension) may declare multiple observer methods.</p>
* <p/>
* <p>Observer methods are inherited by bean subclasses.</p>
* <p/>
* <p>Interceptors and decorators may not declare observer
* methods.</p>
*
* @author Gavin King
* @author Pete Muir
* @author David Allen
*/
@Target(PARAMETER)
@Retention(RUNTIME)
@Documented
public @interface Observes {
/**
* <p>Specifies
* {@linkplain javax.enterprise.event.Reception under what conditions the
* observer method is notified}.</p>
* <p/>
* <p>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.</p>
*/
public Reception notifyObserver() default Reception.ALWAYS;
/**
* <p>Specifies
* {@linkplain javax.enterprise.event.Reception at what time the observer
* method is notified}.</p>
* <p/>
* <p>By default, the observer method is notified when the event is fired.</p>
*/
public TransactionPhase during() default TransactionPhase.IN_PROGRESS;
}