org.springframework.aop.framework.AbstractAdvisingBeanPostProcessor Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.aop.framework;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.springframework.aop.Advisor;
import org.springframework.aop.support.AopUtils;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.lang.Nullable;
/**
* Base class for {@link BeanPostProcessor} implementations that apply a
* Spring AOP {@link Advisor} to specific beans.
*
* @author Juergen Hoeller
* @since 3.2
*/
@SuppressWarnings("serial")
public abstract class AbstractAdvisingBeanPostProcessor extends ProxyProcessorSupport implements BeanPostProcessor {
@Nullable
protected Advisor advisor;
protected boolean beforeExistingAdvisors = false;
private final Map, Boolean> eligibleBeans = new ConcurrentHashMap<>(256);
/**
* Set whether this post-processor's advisor is supposed to apply before
* existing advisors when encountering a pre-advised object.
* Default is "false", applying the advisor after existing advisors, i.e.
* as close as possible to the target method. Switch this to "true" in order
* for this post-processor's advisor to wrap existing advisors as well.
*
Note: Check the concrete post-processor's javadoc whether it possibly
* changes this flag by default, depending on the nature of its advisor.
*/
public void setBeforeExistingAdvisors(boolean beforeExistingAdvisors) {
this.beforeExistingAdvisors = beforeExistingAdvisors;
}
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) {
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) {
if (this.advisor == null || bean instanceof AopInfrastructureBean) {
// Ignore AOP infrastructure such as scoped proxies.
return bean;
}
if (bean instanceof Advised) {
Advised advised = (Advised) bean;
if (!advised.isFrozen() && isEligible(AopUtils.getTargetClass(bean))) {
// Add our local Advisor to the existing proxy's Advisor chain...
if (this.beforeExistingAdvisors) {
advised.addAdvisor(0, this.advisor);
}
else {
advised.addAdvisor(this.advisor);
}
return bean;
}
}
if (isEligible(bean, beanName)) {
ProxyFactory proxyFactory = prepareProxyFactory(bean, beanName);
if (!proxyFactory.isProxyTargetClass()) {
evaluateProxyInterfaces(bean.getClass(), proxyFactory);
}
proxyFactory.addAdvisor(this.advisor);
customizeProxyFactory(proxyFactory);
return proxyFactory.getProxy(getProxyClassLoader());
}
// No proxy needed.
return bean;
}
/**
* Check whether the given bean is eligible for advising with this
* post-processor's {@link Advisor}.
*
Delegates to {@link #isEligible(Class)} for target class checking.
* Can be overridden e.g. to specifically exclude certain beans by name.
*
Note: Only called for regular bean instances but not for existing
* proxy instances which implement {@link Advised} and allow for adding
* the local {@link Advisor} to the existing proxy's {@link Advisor} chain.
* For the latter, {@link #isEligible(Class)} is being called directly,
* with the actual target class behind the existing proxy (as determined
* by {@link AopUtils#getTargetClass(Object)}).
* @param bean the bean instance
* @param beanName the name of the bean
* @see #isEligible(Class)
*/
protected boolean isEligible(Object bean, String beanName) {
return isEligible(bean.getClass());
}
/**
* Check whether the given class is eligible for advising with this
* post-processor's {@link Advisor}.
*
Implements caching of {@code canApply} results per bean target class.
* @param targetClass the class to check against
* @see AopUtils#canApply(Advisor, Class)
*/
protected boolean isEligible(Class targetClass) {
Boolean eligible = this.eligibleBeans.get(targetClass);
if (eligible != null) {
return eligible;
}
if (this.advisor == null) {
return false;
}
eligible = AopUtils.canApply(this.advisor, targetClass);
this.eligibleBeans.put(targetClass, eligible);
return eligible;
}
/**
* Prepare a {@link ProxyFactory} for the given bean.
*
Subclasses may customize the handling of the target instance and in
* particular the exposure of the target class. The default introspection
* of interfaces for non-target-class proxies and the configured advisor
* will be applied afterwards; {@link #customizeProxyFactory} allows for
* late customizations of those parts right before proxy creation.
* @param bean the bean instance to create a proxy for
* @param beanName the corresponding bean name
* @return the ProxyFactory, initialized with this processor's
* {@link ProxyConfig} settings and the specified bean
* @since 4.2.3
* @see #customizeProxyFactory
*/
protected ProxyFactory prepareProxyFactory(Object bean, String beanName) {
ProxyFactory proxyFactory = new ProxyFactory();
proxyFactory.copyFrom(this);
proxyFactory.setTarget(bean);
return proxyFactory;
}
/**
* Subclasses may choose to implement this: for example,
* to change the interfaces exposed.
*
The default implementation is empty.
* @param proxyFactory the ProxyFactory that is already configured with
* target, advisor and interfaces and will be used to create the proxy
* immediately after this method returns
* @since 4.2.3
* @see #prepareProxyFactory
*/
protected void customizeProxyFactory(ProxyFactory proxyFactory) {
}
}