/*
* 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.aop.framework;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.aopalliance.aop.Advice;
import org.aopalliance.intercept.Interceptor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.Advisor;
import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.adapter.AdvisorAdapterRegistry;
import org.springframework.aop.framework.adapter.GlobalAdvisorAdapterRegistry;
import org.springframework.aop.framework.adapter.UnknownAdviceTypeException;
import org.springframework.aop.target.SingletonTargetSource;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.FactoryBeanNotInitializedException;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.core.OrderComparator;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
/**
* {@link org.springframework.beans.factory.FactoryBean} implementation that builds an
* AOP proxy based on beans in Spring {@link org.springframework.beans.factory.BeanFactory}.
*
* <p>{@link org.aopalliance.intercept.MethodInterceptor MethodInterceptors} and
* {@link org.springframework.aop.Advisor Advisors} are identified by a list of bean
* names in the current bean factory, specified through the "interceptorNames" property.
* The last entry in the list can be the name of a target bean or a
* {@link org.springframework.aop.TargetSource}; however, it is normally preferable
* to use the "targetName"/"target"/"targetSource" properties instead.
*
* <p>Global interceptors and advisors can be added at the factory level. The specified
* ones are expanded in an interceptor list where an "xxx*" entry is included in the
* list, matching the given prefix with the bean names (e.g. "global*" would match
* both "globalBean1" and "globalBean2", "*" all defined interceptors). The matching
* interceptors get applied according to their returned order value, if they implement
* the {@link org.springframework.core.Ordered} interface.
*
* <p>Creates a JDK proxy when proxy interfaces are given, and a CGLIB proxy for the
* actual target class if not. Note that the latter will only work if the target class
* does not have final methods, as a dynamic subclass will be created at runtime.
*
* <p>It's possible to cast a proxy obtained from this factory to {@link Advised},
* or to obtain the ProxyFactoryBean reference and programmatically manipulate it.
* This won't work for existing prototype references, which are independent. However,
* it will work for prototypes subsequently obtained from the factory. Changes to
* interception will work immediately on singletons (including existing references).
* However, to change interfaces or target it's necessary to obtain a new instance
* from the factory. This means that singleton instances obtained from the factory
* do not have the same object identity. However, they do have the same interceptors
* and target, and changing any reference will change all objects.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see #setInterceptorNames
* @see #setProxyInterfaces
* @see org.aopalliance.intercept.MethodInterceptor
* @see org.springframework.aop.Advisor
* @see Advised
*/
public class ProxyFactoryBean extends ProxyCreatorSupport
implements FactoryBean<Object>, BeanClassLoaderAware, BeanFactoryAware {
/**
* This suffix in a value in an interceptor list indicates to expand globals.
*/
public static final String GLOBAL_SUFFIX = "*";
protected final Log logger = LogFactory.getLog(getClass());
private String[] interceptorNames;
private String targetName;
private boolean autodetectInterfaces = true;
private boolean singleton = true;
private AdvisorAdapterRegistry advisorAdapterRegistry = GlobalAdvisorAdapterRegistry.getInstance();
private boolean freezeProxy = false;
private transient ClassLoader proxyClassLoader = ClassUtils.getDefaultClassLoader();
private transient boolean classLoaderConfigured = false;
private transient BeanFactory beanFactory;
/** Whether the advisor chain has already been initialized */
private boolean advisorChainInitialized = false;
/** If this is a singleton, the cached singleton proxy instance */
private Object singletonInstance;
/**
* Set the names of the interfaces we're proxying. If no interface
* is given, a CGLIB for the actual class will be created.
* <p>This is essentially equivalent to the "setInterfaces" method,
* but mirrors TransactionProxyFactoryBean's "setProxyInterfaces".
* @see #setInterfaces
* @see AbstractSingletonProxyFactoryBean#setProxyInterfaces
*/
public void setProxyInterfaces(Class[] proxyInterfaces) throws ClassNotFoundException {
setInterfaces(proxyInterfaces);
}
/**
* Set the list of Advice/Advisor bean names. This must always be set
* to use this factory bean in a bean factory.
* <p>The referenced beans should be of type Interceptor, Advisor or Advice
* The last entry in the list can be the name of any bean in the factory.
* If it's neither an Advice nor an Advisor, a new SingletonTargetSource
* is added to wrap it. Such a target bean cannot be used if the "target"
* or "targetSource" or "targetName" property is set, in which case the
* "interceptorNames" array must contain only Advice/Advisor bean names.
* <p><b>NOTE: Specifying a target bean as final name in the "interceptorNames"
* list is deprecated and will be removed in a future Spring version.</b>
* Use the {@link #setTargetName "targetName"} property instead.
* @see org.aopalliance.intercept.MethodInterceptor
* @see org.springframework.aop.Advisor
* @see org.aopalliance.aop.Advice
* @see org.springframework.aop.target.SingletonTargetSource
*/
public void setInterceptorNames(String[] interceptorNames) {
this.interceptorNames = interceptorNames;
}
/**
* Set the name of the target bean. This is an alternative to specifying
* the target name at the end of the "interceptorNames" array.
* <p>You can also specify a target object or a TargetSource object
* directly, via the "target"/"targetSource" property, respectively.
* @see #setInterceptorNames(String[])
* @see #setTarget(Object)
* @see #setTargetSource(org.springframework.aop.TargetSource)
*/
public void setTargetName(String targetName) {
this.targetName = targetName;
}
/**
* Set whether to autodetect proxy interfaces if none specified.
* <p>Default is "true". Turn this flag off to create a CGLIB
* proxy for the full target class if no interfaces specified.
* @see #setProxyTargetClass
*/
public void setAutodetectInterfaces(boolean autodetectInterfaces) {
this.autodetectInterfaces = autodetectInterfaces;
}
/**
* Set the value of the singleton property. Governs whether this factory
* should always return the same proxy instance (which implies the same target)
* or whether it should return a new prototype instance, which implies that
* the target and interceptors may be new instances also, if they are obtained
* from prototype bean definitions. This allows for fine control of
* independence/uniqueness in the object graph.
*/
public void setSingleton(boolean singleton) {
this.singleton = singleton;
}
/**
* Specify the AdvisorAdapterRegistry to use.
* Default is the global AdvisorAdapterRegistry.
* @see org.springframework.aop.framework.adapter.GlobalAdvisorAdapterRegistry
*/
public void setAdvisorAdapterRegistry(AdvisorAdapterRegistry advisorAdapterRegistry) {
this.advisorAdapterRegistry = advisorAdapterRegistry;
}
@Override
public void setFrozen(boolean frozen) {
this.freezeProxy = frozen;
}
/**
* Set the ClassLoader to generate the proxy class in.
* <p>Default is the bean ClassLoader, i.e. the ClassLoader used by the
* containing BeanFactory for loading all bean classes. This can be
* overridden here for specific proxies.
*/
public void setProxyClassLoader(ClassLoader classLoader) {
this.proxyClassLoader = classLoader;
this.classLoaderConfigured = (classLoader != null);
}
public void setBeanClassLoader(ClassLoader classLoader) {
if (!this.classLoaderConfigured) {
this.proxyClassLoader = classLoader;
}
}
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
checkInterceptorNames();
}
/**
* Return a proxy. Invoked when clients obtain beans from this factory bean.
* Create an instance of the AOP proxy to be returned by this factory.
* The instance will be cached for a singleton, and create on each call to
* <code>getObject()</code> for a proxy.
* @return a fresh AOP proxy reflecting the current state of this factory
*/
public Object getObject() throws BeansException {
initializeAdvisorChain();
if (isSingleton()) {
return getSingletonInstance();
}
else {
if (this.targetName == null) {
logger.warn("Using non-singleton proxies with singleton targets is often undesirable. " +
"Enable prototype proxies by setting the 'targetName' property.");
}
return newPrototypeInstance();
}
}
/**
* Return the type of the proxy. Will check the singleton instance if
* already created, else fall back to the proxy interface (in case of just
* a single one), the target bean type, or the TargetSource's target class.
* @see org.springframework.aop.TargetSource#getTargetClass
*/
public Class<?> getObjectType() {
synchronized (this) {
if (this.singletonInstance != null) {
return this.singletonInstance.getClass();
}
}
Class[] ifcs = getProxiedInterfaces();
if (ifcs.length == 1) {
return ifcs[0];
}
else if (ifcs.length > 1) {
return createCompositeInterface(ifcs);
}
else if (this.targetName != null && this.beanFactory != null) {
return this.beanFactory.getType(this.targetName);
}
else {
return getTargetClass();
}
}
public boolean isSingleton() {
return this.singleton;
}
/**
* Create a composite interface Class for the given interfaces,
* implementing the given interfaces in one single Class.
* <p>The default implementation builds a JDK proxy class for the
* given interfaces.
* @param interfaces the interfaces to merge
* @return the merged interface as Class
* @see java.lang.reflect.Proxy#getProxyClass
*/
protected Class createCompositeInterface(Class[] interfaces) {
return ClassUtils.createCompositeInterface(interfaces, this.proxyClassLoader);
}
/**
* Return the singleton instance of this class's proxy object,
* lazily creating it if it hasn't been created already.
* @return the shared singleton proxy
*/
private synchronized Object getSingletonInstance() {
if (this.singletonInstance == null) {
this.targetSource = freshTargetSource();
if (this.autodetectInterfaces && getProxiedInterfaces().length == 0 && !isProxyTargetClass()) {
// Rely on AOP infrastructure to tell us what interfaces to proxy.
Class targetClass = getTargetClass();
if (targetClass == null) {
throw new FactoryBeanNotInitializedException("Cannot determine target class for proxy");
}
setInterfaces(ClassUtils.getAllInterfacesForClass(targetClass, this.proxyClassLoader));
}
// Initialize the shared singleton instance.
super.setFrozen(this.freezeProxy);
this.singletonInstance = getProxy(createAopProxy());
}
return this.singletonInstance;
}
/**
* Create a new prototype instance of this class's created proxy object,
* backed by an independent AdvisedSupport configuration.
* @return a totally independent proxy, whose advice we may manipulate in isolation
*/
private synchronized Object newPrototypeInstance() {
// In the case of a prototype, we need to give the proxy
// an independent instance of the configuration.
// In this case, no proxy will have an instance of this object's configuration,
// but will have an independent copy.
if (logger.isTraceEnabled()) {
logger.trace("Creating copy of prototype ProxyFactoryBean config: " + this);
}
ProxyCreatorSupport copy = new ProxyCreatorSupport(getAopProxyFactory());
// The copy needs a fresh advisor chain, and a fresh TargetSource.
TargetSource targetSource = freshTargetSource();
copy.copyConfigurationFrom(this, targetSource, freshAdvisorChain());
if (this.autodetectInterfaces && getProxiedInterfaces().length == 0 && !isProxyTargetClass()) {
// Rely on AOP infrastructure to tell us what interfaces to proxy.
copy.setInterfaces(
ClassUtils.getAllInterfacesForClass(targetSource.getTargetClass(), this.proxyClassLoader));
}
copy.setFrozen(this.freezeProxy);
if (logger.isTraceEnabled()) {
logger.trace("Using ProxyCreatorSupport copy: " + copy);
}
return getProxy(copy.createAopProxy());
}
/**
* Return the proxy object to expose.
* <p>The default implementation uses a <code>getProxy</code> call with
* the factory's bean class loader. Can be overridden to specify a
* custom class loader.
* @param aopProxy the prepared AopProxy instance to get the proxy from
* @return the proxy object to expose
* @see AopProxy#getProxy(ClassLoader)
*/
protected Object getProxy(AopProxy aopProxy) {
return aopProxy.getProxy(this.proxyClassLoader);
}
/**
* Check the interceptorNames list whether it contains a target name as final element.
* If found, remove the final name from the list and set it as targetName.
*/
private void checkInterceptorNames() {
if (!ObjectUtils.isEmpty(this.interceptorNames)) {
String finalName = this.interceptorNames[this.interceptorNames.length - 1];
if (this.targetName == null && this.targetSource == EMPTY_TARGET_SOURCE) {
// The last name in the chain may be an Advisor/Advice or a target/TargetSource.
// Unfortunately we don't know; we must look at type of the bean.
if (!finalName.endsWith(GLOBAL_SUFFIX) && !isNamedBeanAnAdvisorOrAdvice(finalName)) {
// The target isn't an interceptor.
this.targetName = finalName;
if (logger.isDebugEnabled()) {
logger.debug("Bean with name '" + finalName + "' concluding interceptor chain " +
"is not an advisor class: treating it as a target or TargetSource");
}
String[] newNames = new String[this.interceptorNames.length - 1];
System.arraycopy(this.interceptorNames, 0, newNames, 0, newNames.length);
this.interceptorNames = newNames;
}
}
}
}
/**
* Look at bean factory metadata to work out whether this bean name,
* which concludes the interceptorNames list, is an Advisor or Advice,
* or may be a target.
* @param beanName bean name to check
* @return <code>true</code> if it's an Advisor or Advice
*/
private boolean isNamedBeanAnAdvisorOrAdvice(String beanName) {
Class namedBeanClass = this.beanFactory.getType(beanName);
if (namedBeanClass != null) {
return (Advisor.class.isAssignableFrom(namedBeanClass) || Advice.class.isAssignableFrom(namedBeanClass));
}
// Treat it as an target bean if we can't tell.
if (logger.isDebugEnabled()) {
logger.debug("Could not determine type of bean with name '" + beanName +
"' - assuming it is neither an Advisor nor an Advice");
}
return false;
}
/**
* Create the advisor (interceptor) chain. Aadvisors that are sourced
* from a BeanFactory will be refreshed each time a new prototype instance
* is added. Interceptors added programmatically through the factory API
* are unaffected by such changes.
*/
private synchronized void initializeAdvisorChain() throws AopConfigException, BeansException {
if (this.advisorChainInitialized) {
return;
}
if (!ObjectUtils.isEmpty(this.interceptorNames)) {
if (this.beanFactory == null) {
throw new IllegalStateException("No BeanFactory available anymore (probably due to serialization) " +
"- cannot resolve interceptor names " + Arrays.asList(this.interceptorNames));
}
// Globals can't be last unless we specified a targetSource using the property...
if (this.interceptorNames[this.interceptorNames.length - 1].endsWith(GLOBAL_SUFFIX) &&
this.targetName == null && this.targetSource == EMPTY_TARGET_SOURCE) {
throw new AopConfigException("Target required after globals");
}
// Materialize interceptor chain from bean names.
for (String name : this.interceptorNames) {
if (logger.isTraceEnabled()) {
logger.trace("Configuring advisor or advice '" + name + "'");
}
if (name.endsWith(GLOBAL_SUFFIX)) {
if (!(this.beanFactory instanceof ListableBeanFactory)) {
throw new AopConfigException(
"Can only use global advisors or interceptors with a ListableBeanFactory");
}
addGlobalAdvisor((ListableBeanFactory) this.beanFactory,
name.substring(0, name.length() - GLOBAL_SUFFIX.length()));
}
else {
// If we get here, we need to add a named interceptor.
// We must check if it's a singleton or prototype.
Object advice;
if (this.singleton || this.beanFactory.isSingleton(name)) {
// Add the real Advisor/Advice to the chain.
advice = this.beanFactory.getBean(name);
}
else {
// It's a prototype Advice or Advisor: replace with a prototype.
// Avoid unnecessary creation of prototype bean just for advisor chain initialization.
advice = new PrototypePlaceholderAdvisor(name);
}
addAdvisorOnChainCreation(advice, name);
}
}
}
this.advisorChainInitialized = true;
}
/**
* Return an independent advisor chain.
* We need to do this every time a new prototype instance is returned,
* to return distinct instances of prototype Advisors and Advices.
*/
private List<Advisor> freshAdvisorChain() {
Advisor[] advisors = getAdvisors();
List<Advisor> freshAdvisors = new ArrayList<Advisor>(advisors.length);
for (Advisor advisor : advisors) {
if (advisor instanceof PrototypePlaceholderAdvisor) {
PrototypePlaceholderAdvisor pa = (PrototypePlaceholderAdvisor) advisor;
if (logger.isDebugEnabled()) {
logger.debug("Refreshing bean named '" + pa.getBeanName() + "'");
}
// Replace the placeholder with a fresh prototype instance resulting
// from a getBean() lookup
if (this.beanFactory == null) {
throw new IllegalStateException("No BeanFactory available anymore (probably due to serialization) " +
"- cannot resolve prototype advisor '" + pa.getBeanName() + "'");
}
Object bean = this.beanFactory.getBean(pa.getBeanName());
Advisor refreshedAdvisor = namedBeanToAdvisor(bean);
freshAdvisors.add(refreshedAdvisor);
}
else {
// Add the shared instance.
freshAdvisors.add(advisor);
}
}
return freshAdvisors;
}
/**
* Add all global interceptors and pointcuts.
*/
private void addGlobalAdvisor(ListableBeanFactory beanFactory, String prefix) {
String[] globalAdvisorNames =
BeanFactoryUtils.beanNamesForTypeIncludingAncestors(beanFactory, Advisor.class);
String[] globalInterceptorNames =
BeanFactoryUtils.beanNamesForTypeIncludingAncestors(beanFactory, Interceptor.class);
List<Object> beans = new ArrayList<Object>(globalAdvisorNames.length + globalInterceptorNames.length);
Map<Object, String> names = new HashMap<Object, String>(beans.size());
for (String name : globalAdvisorNames) {
Object bean = beanFactory.getBean(name);
beans.add(bean);
names.put(bean, name);
}
for (String name : globalInterceptorNames) {
Object bean = beanFactory.getBean(name);
beans.add(bean);
names.put(bean, name);
}
OrderComparator.sort(beans);
for (Object bean : beans) {
String name = names.get(bean);
if (name.startsWith(prefix)) {
addAdvisorOnChainCreation(bean, name);
}
}
}
/**
* Invoked when advice chain is created.
* <p>Add the given advice, advisor or object to the interceptor list.
* Because of these three possibilities, we can't type the signature
* more strongly.
* @param next advice, advisor or target object
* @param name bean name from which we obtained this object in our owning
* bean factory
*/
private void addAdvisorOnChainCreation(Object next, String name) {
// We need to convert to an Advisor if necessary so that our source reference
// matches what we find from superclass interceptors.
Advisor advisor = namedBeanToAdvisor(next);
if (logger.isTraceEnabled()) {
logger.trace("Adding advisor with name '" + name + "'");
}
addAdvisor(advisor);
}
/**
* Return a TargetSource to use when creating a proxy. If the target was not
* specified at the end of the interceptorNames list, the TargetSource will be
* this class's TargetSource member. Otherwise, we get the target bean and wrap
* it in a TargetSource if necessary.
*/
private TargetSource freshTargetSource() {
if (this.targetName == null) {
if (logger.isTraceEnabled()) {
logger.trace("Not refreshing target: Bean name not specified in 'interceptorNames'.");
}
return this.targetSource;
}
else {
if (this.beanFactory == null) {
throw new IllegalStateException("No BeanFactory available anymore (probably due to serialization) " +
"- cannot resolve target with name '" + this.targetName + "'");
}
if (logger.isDebugEnabled()) {
logger.debug("Refreshing target with name '" + this.targetName + "'");
}
Object target = this.beanFactory.getBean(this.targetName);
return (target instanceof TargetSource ? (TargetSource) target : new SingletonTargetSource(target));
}
}
/**
* Convert the following object sourced from calling getBean() on a name in the
* interceptorNames array to an Advisor or TargetSource.
*/
private Advisor namedBeanToAdvisor(Object next) {
try {
return this.advisorAdapterRegistry.wrap(next);
}
catch (UnknownAdviceTypeException ex) {
// We expected this to be an Advisor or Advice,
// but it wasn't. This is a configuration error.
throw new AopConfigException("Unknown advisor type " + next.getClass() +
"; Can only include Advisor or Advice type beans in interceptorNames chain except for last entry," +
"which may also be target or TargetSource", ex);
}
}
/**
* Blow away and recache singleton on an advice change.
*/
@Override
protected void adviceChanged() {
super.adviceChanged();
if (this.singleton) {
logger.debug("Advice has changed; recaching singleton instance");
synchronized (this) {
this.singletonInstance = null;
}
}
}
//---------------------------------------------------------------------
// Serialization support
//---------------------------------------------------------------------
private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
// Rely on default serialization; just initialize state after deserialization.
ois.defaultReadObject();
// Initialize transient fields.
this.proxyClassLoader = ClassUtils.getDefaultClassLoader();
}
/**
* Used in the interceptor chain where we need to replace a bean with a prototype
* on creating a proxy.
*/
private static class PrototypePlaceholderAdvisor implements Advisor, Serializable {
private final String beanName;
private final String message;
public PrototypePlaceholderAdvisor(String beanName) {
this.beanName = beanName;
this.message = "Placeholder for prototype Advisor/Advice with bean name '" + beanName + "'";
}
public String getBeanName() {
return beanName;
}
public Advice getAdvice() {
throw new UnsupportedOperationException("Cannot invoke methods: " + this.message);
}
public boolean isPerInstance() {
throw new UnsupportedOperationException("Cannot invoke methods: " + this.message);
}
@Override
public String toString() {
return this.message;
}
}
}
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