/*
* Copyright 2002-2009 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.concurrent.Executor;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
/**
* Simple implementation of the {@link ApplicationEventMulticaster} interface.
*
* <p>Multicasts all events to all registered listeners, leaving it up to
* the listeners to ignore events that they are not interested in.
* Listeners will usually perform corresponding <code>instanceof</code>
* checks on the passed-in event object.
*
* <p>By default, all listeners are invoked in the calling thread.
* This allows the danger of a rogue listener blocking the entire application,
* but adds minimal overhead. Specify an alternative TaskExecutor to have
* listeners executed in different threads, for example from a thread pool.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see #setTaskExecutor
*/
public class SimpleApplicationEventMulticaster extends AbstractApplicationEventMulticaster {
private Executor taskExecutor;
/**
* Create a new SimpleApplicationEventMulticaster.
*/
public SimpleApplicationEventMulticaster() {
}
/**
* Create a new SimpleApplicationEventMulticaster for the given BeanFactory.
*/
public SimpleApplicationEventMulticaster(BeanFactory beanFactory) {
setBeanFactory(beanFactory);
}
/**
* Set the TaskExecutor to execute application listeners with.
* <p>Default is a SyncTaskExecutor, executing the listeners synchronously
* in the calling thread.
* <p>Consider specifying an asynchronous TaskExecutor here to not block the
* caller until all listeners have been executed. However, note that asynchronous
* execution will not participate in the caller's thread context (class loader,
* transaction association) unless the TaskExecutor explicitly supports this.
* @see org.springframework.core.task.SyncTaskExecutor
* @see org.springframework.core.task.SimpleAsyncTaskExecutor
*/
public void setTaskExecutor(Executor taskExecutor) {
this.taskExecutor = taskExecutor;
}
/**
* Return the current TaskExecutor for this multicaster.
*/
protected Executor getTaskExecutor() {
return this.taskExecutor;
}
@SuppressWarnings("unchecked")
public void multicastEvent(final ApplicationEvent event) {
for (final ApplicationListener listener : getApplicationListeners(event)) {
Executor executor = getTaskExecutor();
if (executor != null) {
executor.execute(new Runnable() {
@SuppressWarnings("unchecked")
public void run() {
listener.onApplicationEvent(event);
}
});
}
else {
listener.onApplicationEvent(event);
}
}
}
}
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