org.springframework.context.event.EventListenerMethodProcessor Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.framework.autoproxy.AutoProxyUtils;
import org.springframework.aop.scope.ScopedObject;
import org.springframework.aop.scope.ScopedProxyUtils;
import org.springframework.aop.support.AopUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.SmartInitializingSingleton;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.MethodIntrospector;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
/**
* Register {@link EventListener} annotated method as individual {@link ApplicationListener}
* instances.
*
* @author Stephane Nicoll
* @author Juergen Hoeller
* @since 4.2
*/
public class EventListenerMethodProcessor implements SmartInitializingSingleton, ApplicationContextAware {
protected final Log logger = LogFactory.getLog(getClass());
private ConfigurableApplicationContext applicationContext;
private final EventExpressionEvaluator evaluator = new EventExpressionEvaluator();
private final Set> nonAnnotatedClasses =
Collections.newSetFromMap(new ConcurrentHashMap, Boolean>(64));
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
Assert.isTrue(applicationContext instanceof ConfigurableApplicationContext,
"ApplicationContext does not implement ConfigurableApplicationContext");
this.applicationContext = (ConfigurableApplicationContext) applicationContext;
}
@Override
public void afterSingletonsInstantiated() {
List factories = getEventListenerFactories();
String[] beanNames = this.applicationContext.getBeanNamesForType(Object.class);
for (String beanName : beanNames) {
if (!ScopedProxyUtils.isScopedTarget(beanName)) {
Class type = null;
try {
type = AutoProxyUtils.determineTargetClass(this.applicationContext.getBeanFactory(), beanName);
}
catch (Throwable ex) {
// An unresolvable bean type, probably from a lazy bean - let's ignore it.
if (logger.isDebugEnabled()) {
logger.debug("Could not resolve target class for bean with name '" + beanName + "'", ex);
}
}
if (type != null) {
if (ScopedObject.class.isAssignableFrom(type)) {
try {
type = AutoProxyUtils.determineTargetClass(this.applicationContext.getBeanFactory(),
ScopedProxyUtils.getTargetBeanName(beanName));
}
catch (Throwable ex) {
// An invalid scoped proxy arrangement - let's ignore it.
if (logger.isDebugEnabled()) {
logger.debug("Could not resolve target bean for scoped proxy '" + beanName + "'", ex);
}
}
}
try {
processBean(factories, beanName, type);
}
catch (Throwable ex) {
throw new BeanInitializationException("Failed to process @EventListener " +
"annotation on bean with name '" + beanName + "'", ex);
}
}
}
}
}
/**
* Return the {@link EventListenerFactory} instances to use to handle
* {@link EventListener} annotated methods.
*/
protected List getEventListenerFactories() {
Map beans = this.applicationContext.getBeansOfType(EventListenerFactory.class);
List allFactories = new ArrayList(beans.values());
AnnotationAwareOrderComparator.sort(allFactories);
return allFactories;
}
protected void processBean(final List factories, final String beanName, final Class targetType) {
if (!this.nonAnnotatedClasses.contains(targetType)) {
Map annotatedMethods = null;
try {
annotatedMethods = MethodIntrospector.selectMethods(targetType,
new MethodIntrospector.MetadataLookup() {
@Override
public EventListener inspect(Method method) {
return AnnotatedElementUtils.findMergedAnnotation(method, EventListener.class);
}
});
}
catch (Throwable ex) {
// An unresolvable type in a method signature, probably from a lazy bean - let's ignore it.
if (logger.isDebugEnabled()) {
logger.debug("Could not resolve methods for bean with name '" + beanName + "'", ex);
}
}
if (CollectionUtils.isEmpty(annotatedMethods)) {
this.nonAnnotatedClasses.add(targetType);
if (logger.isTraceEnabled()) {
logger.trace("No @EventListener annotations found on bean class: " + targetType.getName());
}
}
else {
// Non-empty set of methods
for (Method method : annotatedMethods.keySet()) {
for (EventListenerFactory factory : factories) {
if (factory.supportsMethod(method)) {
Method methodToUse = AopUtils.selectInvocableMethod(
method, this.applicationContext.getType(beanName));
ApplicationListener applicationListener =
factory.createApplicationListener(beanName, targetType, methodToUse);
if (applicationListener instanceof ApplicationListenerMethodAdapter) {
((ApplicationListenerMethodAdapter) applicationListener)
.init(this.applicationContext, this.evaluator);
}
this.applicationContext.addApplicationListener(applicationListener);
break;
}
}
}
if (logger.isDebugEnabled()) {
logger.debug(annotatedMethods.size() + " @EventListener methods processed on bean '" +
beanName + "': " + annotatedMethods);
}
}
}
}
}