org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator 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.aop.framework.autoproxy;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import org.springframework.aop.Advisor;
import org.springframework.aop.TargetSource;
import org.springframework.aop.support.AopUtils;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.core.ControlFlow;
import org.springframework.core.ControlFlowFactory;
import org.springframework.core.OrderComparator;
/**
* Abstract BeanPostProcessor implementation that creates AOP proxies.
* This class is completely generic; it contains no special code to handle
* any particular aspects, such as pooling aspects.
*
* Subclasses must implement the abstract findCandidateAdvisors() method
* to return a list of Advisors applying to any object. Subclasses can also
* override the inherited shouldSkip() method to exclude certain objects
* from autoproxying, but they must be careful to invoke the shouldSkip()
* method of this class, which tries to avoid circular reference problems
* and infinite loops.
*
*
Advisors or advices requiring ordering should implement the Ordered interface.
* This class sorts advisors by Ordered order value. Advisors that don't implement
* the Ordered interface will be considered to be unordered, and will appear
* at the end of the advisor chain in undefined order.
*
* @author Rod Johnson
* @see #findCandidateAdvisors
*/
public abstract class AbstractAdvisorAutoProxyCreator extends AbstractAutoProxyCreator {
/**
* We override this method to ensure that all candidate advisors are materialized
* under a stack trace including this bean. Otherwise, the dependencies won't
* be apparent to the circular-reference prevention strategy in AbstractBeanFactory.
*/
public void setBeanFactory(BeanFactory beanFactory) {
super.setBeanFactory(beanFactory);
findCandidateAdvisors();
}
protected Object[] getAdvicesAndAdvisorsForBean(Object bean, String name, TargetSource targetSource) {
List advisors = findEligibleAdvisors(bean.getClass());
if (advisors.isEmpty()) {
return DO_NOT_PROXY;
}
advisors = sortAdvisors(advisors);
return advisors.toArray();
}
/**
* Find all eligible advices and for autoproxying this class.
* @return the empty list, not null, if there are no pointcuts or interceptors
* @see #findCandidateAdvisors
*/
protected List findEligibleAdvisors(Class clazz) {
List candidateAdvisors = findCandidateAdvisors();
List eligibleAdvisors = new LinkedList();
for (int i = 0; i < candidateAdvisors.size(); i++) {
// Sun, give me generics, please!
Advisor candidate = (Advisor) candidateAdvisors.get(i);
if (AopUtils.canApply(candidate, clazz, null)) {
eligibleAdvisors.add(candidate);
if (logger.isInfoEnabled()) {
logger.info("Candidate advisor [" + candidate + "] accepted for class [" + clazz.getName() + "]");
}
}
else {
if (logger.isInfoEnabled()) {
logger.info("Candidate advisor [" + candidate + "] rejected for class [" + clazz.getName() + "]");
}
}
}
return eligibleAdvisors;
}
/**
* Sort advisors based on ordering.
* @see org.springframework.core.Ordered
* @see org.springframework.core.OrderComparator
*/
protected List sortAdvisors(List advisors) {
Collections.sort(advisors, new OrderComparator());
return advisors;
}
/**
* We override this to ensure that we don't get into circular reference hell
* when our own infrastructure (such as this class) depends on advisors that depend
* on beans... We use a ControlFlow object to check that we didn't arrived at this
* call via this classes findCandidateAdvisors() method.
* @see org.springframework.core.ControlFlow
*/
protected boolean shouldSkip(Object bean, String name) {
// TODO consider pulling this test into AbstractBeanFactory.applyPostProcessors(),
// to protect all PostProcessors.
ControlFlow cflow = ControlFlowFactory.createControlFlow();
return cflow.under(getClass(), "findCandidateAdvisors");
}
/**
* Find all candidate advisors to use in auto-proxying.
* @return list of Advisors
*/
protected abstract List findCandidateAdvisors();
}