jakarta.enterprise.event.Event Maven / Gradle / Ivy
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* JBoss, Home of Professional Open Source
* Copyright 2010, 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 java.lang.annotation.Annotation;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.Executor;
import jakarta.enterprise.util.TypeLiteral;
import jakarta.enterprise.inject.Any;
/**
*
* Allows the application to fire events of a particular type.
*
*
*
* Beans fire events via an instance of the Event interface, which may be injected:
*
*
*
* @Inject
* @Any
* Event<LoggedInEvent> loggedInEvent;
*
*
*
* The fire() method accepts an event object:
*
*
*
* public void login() {
* ...
* loggedInEvent.fire( new LoggedInEvent(user) );
* }
*
*
*
* Any combination of qualifiers may be specified at the injection point:
*
*
*
* @Inject
* @Admin
* Event<LoggedInEvent> adminLoggedInEvent;
*
*
*
* Or, the {@link Any @Any} qualifier may be used, allowing the application to specify qualifiers
* dynamically:
*
*
*
* @Inject
* @Any
* Event<LoggedInEvent> loggedInEvent;
*
*
*
* For an injected Event:
*
*
*
* - the specified type is the type parameter specified at the injection point, and
* - the specified qualifiers are the qualifiers specified at the injection point.
*
*
*
* Events may also be fired asynchronously with {@link #fireAsync(Object)} and {@link #fireAsync(Object, NotificationOptions)} methods
*
*
* @author Gavin King
* @author Pete Muir
* @author David Allen
* @author Antoine Sabot-Durand
*
* @param the type of the event object
*/
public interface Event {
/**
*
* Fires an event with the specified qualifiers and notifies observers.
*
*
* @param event the event object
* @throws IllegalArgumentException if the runtime type of the event object contains a type variable
* @throws ObserverException if a notified observer throws a checked exception, it will be wrapped and rethrown as an
* (unchecked) {@link ObserverException}
*/
public void fire(T event);
/**
*
* Fires an event asynchronously with the specified qualifiers and notifies asynchronous observers.
*
*
* @param event type
* @param event the event object
* @return a {@link CompletionStage} allowing further pipeline composition on the asynchronous operation.
* Default asynchronous execution facility is container specific.
* If any observer notified by this event throws an exception
* then the resulting CompletionStage is completed exceptionally with {@link java.util.concurrent.CompletionException}
* that wraps all the exceptions raised by observers as suppressed exception.
* If no exception is thrown by observers then the resulting CompletionStage is completed normally with the event payload.
* @throws IllegalArgumentException if the runtime type of the event object contains a type variable
*
* @since 2.0
*/
public CompletionStage fireAsync(U event);
/**
*
* Fires an event asynchronously with the specified qualifiers and notifies asynchronous observers.
* A custom {@link Executor} will be used to make asynchronous calls
*
*
* @param event type
* @param event the event object
* @param options the notification options
* @return a {@link CompletionStage} allowing further pipeline composition on the asynchronous operation.
* Default asynchronous execution facility is container specific.
* If any observer notified by this event throws an exception
* then the resulting CompletionStage is completed exceptionally with {@link java.util.concurrent.CompletionException}
* that wraps all the exceptions raised by observers as suppressed exception.
* If no exception is thrown by observers then the resulting CompletionStage is completed normally with the event payload.
* @throws IllegalArgumentException if the runtime type of the event object contains a type variable
*
* @since 2.0
*/
public CompletionStage fireAsync(U event, NotificationOptions options);
/**
*
* Obtains a child Event for the given additional required qualifiers.
*
*
* @param qualifiers the additional specified qualifiers
* @return the child Event
* @throws IllegalArgumentException if passed two instances of the same non repeating qualifier type, or an instance of an annotation that
* is not a qualifier type
*/
public Event select(Annotation... qualifiers);
/**
*
* Obtains a child Event for the given required type and additional required qualifiers.
*
*
* @param the specified type
* @param subtype a {@link java.lang.Class} representing the specified type
* @param qualifiers the additional specified qualifiers
* @return the child Event
* @throws IllegalArgumentException if passed two instances of the same non repeating qualifier type, or an instance of an annotation that
* is not a qualifier type
*/
public Event select(Class subtype, Annotation... qualifiers);
/**
*
* Obtains a child Event for the given required type and additional required qualifiers.
*
*
* @param the specified type
* @param subtype a {@link TypeLiteral} representing the specified type
* @param qualifiers the additional specified qualifiers
* @return the child Event
* @throws IllegalArgumentException if passed two instances of the same non repeating qualifier type, or an instance of an annotation that
* is not a qualifier type
*/
public Event select(TypeLiteral subtype, Annotation... qualifiers);
}