001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.context.event;
018
019import org.springframework.context.ApplicationEvent;
020import org.springframework.context.ApplicationListener;
021import org.springframework.core.ResolvableType;
022
023/**
024 * Interface to be implemented by objects that can manage a number of
025 * {@link ApplicationListener} objects, and publish events to them.
026 *
027 * <p>An {@link org.springframework.context.ApplicationEventPublisher}, typically
028 * a Spring {@link org.springframework.context.ApplicationContext}, can use an
029 * ApplicationEventMulticaster as a delegate for actually publishing events.
030 *
031 * @author Rod Johnson
032 * @author Juergen Hoeller
033 * @author Stephane Nicoll
034 */
035public interface ApplicationEventMulticaster {
036
037        /**
038         * Add a listener to be notified of all events.
039         * @param listener the listener to add
040         */
041        void addApplicationListener(ApplicationListener<?> listener);
042
043        /**
044         * Add a listener bean to be notified of all events.
045         * @param listenerBeanName the name of the listener bean to add
046         */
047        void addApplicationListenerBean(String listenerBeanName);
048
049        /**
050         * Remove a listener from the notification list.
051         * @param listener the listener to remove
052         */
053        void removeApplicationListener(ApplicationListener<?> listener);
054
055        /**
056         * Remove a listener bean from the notification list.
057         * @param listenerBeanName the name of the listener bean to add
058         */
059        void removeApplicationListenerBean(String listenerBeanName);
060
061        /**
062         * Remove all listeners registered with this multicaster.
063         * <p>After a remove call, the multicaster will perform no action
064         * on event notification until new listeners are being registered.
065         */
066        void removeAllListeners();
067
068        /**
069         * Multicast the given application event to appropriate listeners.
070         * <p>Consider using {@link #multicastEvent(ApplicationEvent, ResolvableType)}
071         * if possible as it provides a better support for generics-based events.
072         * @param event the event to multicast
073         */
074        void multicastEvent(ApplicationEvent event);
075
076        /**
077         * Multicast the given application event to appropriate listeners.
078         * <p>If the {@code eventType} is {@code null}, a default type is built
079         * based on the {@code event} instance.
080         * @param event the event to multicast
081         * @param eventType the type of event (can be null)
082         * @since 4.2
083         */
084        void multicastEvent(ApplicationEvent event, ResolvableType eventType);
085
086}