org.springframework.context.event.SimpleApplicationEventMulticaster Maven / Gradle / Ivy
/*
* Copyright 2002-2004 the original author or authors.
*
* 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 org.springframework.context.event;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
/**
* Simple implementation of the ApplicationEventMulticaster interface.
* Multicasts all events to all registered listeners.
*
* Doesn't permit multiple instances of the same listener, as it keeps
* listeners in a HashSet.
*
*
Note that this class doesn't try to do anything clever to ensure thread
* safety if listeners are added or removed at runtime. A technique such as
* Copy-on-Write (Lea:137) could be used to ensure this, but the assumption in
* this version of this framework is that listeners will be added at application
* configuration time and not added or removed as the application runs.
*
*
All listeners are invoked in the calling thread. This allows the danger of
* a rogue listener blocking the entire application, but adds minimal overhead.
*
*
An alternative implementation could be more sophisticated in both these respects.
*
* @author Rod Johnson
* @author Juergen Hoeller
*/
public class SimpleApplicationEventMulticaster implements ApplicationEventMulticaster {
/** Set of listeners */
private final Set applicationListeners = new HashSet();
public void addApplicationListener(ApplicationListener listener) {
this.applicationListeners.add(listener);
}
public void removeApplicationListener(ApplicationListener listener) {
this.applicationListeners.remove(listener);
}
public void removeAllListeners() {
this.applicationListeners.clear();
}
public void multicastEvent(ApplicationEvent event) {
Iterator it = this.applicationListeners.iterator();
while (it.hasNext()) {
ApplicationListener listener = (ApplicationListener) it.next();
listener.onApplicationEvent(event);
}
}
}