/*
* Copyright 2002-2008 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.target;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.AopInfrastructureBean;
import org.springframework.aop.framework.autoproxy.TargetSourceCreator;
import org.springframework.aop.target.AbstractBeanFactoryBasedTargetSource;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.support.GenericBeanDefinition;
/**
* Convenient superclass for
* {@link org.springframework.aop.framework.autoproxy.TargetSourceCreator}
* implementations that require creating multiple instances of a prototype bean.
*
* <p>Uses an internal BeanFactory to manage the target instances,
* copying the original bean definition to this internal factory.
* This is necessary because the original BeanFactory will just
* contain the proxy instance created through auto-proxying.
*
* <p>Requires running in an
* {@link org.springframework.beans.factory.support.AbstractBeanFactory}.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see org.springframework.aop.target.AbstractBeanFactoryBasedTargetSource
* @see org.springframework.beans.factory.support.AbstractBeanFactory
*/
public abstract class AbstractBeanFactoryBasedTargetSourceCreator
implements TargetSourceCreator, BeanFactoryAware, DisposableBean {
protected final Log logger = LogFactory.getLog(getClass());
private ConfigurableBeanFactory beanFactory;
/** Internally used DefaultListableBeanFactory instances, keyed by bean name */
private final Map internalBeanFactories = new HashMap();
public final void setBeanFactory(BeanFactory beanFactory) {
if (!(beanFactory instanceof ConfigurableBeanFactory)) {
throw new IllegalStateException("Cannot do auto-TargetSource creation with a BeanFactory " +
"that doesn't implement ConfigurableBeanFactory: " + beanFactory.getClass());
}
this.beanFactory = (ConfigurableBeanFactory) beanFactory;
}
/**
* Return the BeanFactory that this TargetSourceCreators runs in.
*/
protected final BeanFactory getBeanFactory() {
return this.beanFactory;
}
//---------------------------------------------------------------------
// Implementation of the TargetSourceCreator interface
//---------------------------------------------------------------------
public final TargetSource getTargetSource(Class beanClass, String beanName) {
AbstractBeanFactoryBasedTargetSource targetSource =
createBeanFactoryBasedTargetSource(beanClass, beanName);
if (targetSource == null) {
return null;
}
if (logger.isDebugEnabled()) {
logger.debug("Configuring AbstractBeanFactoryBasedTargetSource: " + targetSource);
}
DefaultListableBeanFactory internalBeanFactory = getInternalBeanFactoryForBean(beanName);
// We need to override just this bean definition, as it may reference other beans
// and we're happy to take the parent's definition for those.
// Always use prototype scope if demanded.
BeanDefinition bd = this.beanFactory.getMergedBeanDefinition(beanName);
GenericBeanDefinition bdCopy = new GenericBeanDefinition(bd);
if (isPrototypeBased()) {
bdCopy.setScope(BeanDefinition.SCOPE_PROTOTYPE);
}
internalBeanFactory.registerBeanDefinition(beanName, bdCopy);
// Complete configuring the PrototypeTargetSource.
targetSource.setTargetBeanName(beanName);
targetSource.setBeanFactory(internalBeanFactory);
return targetSource;
}
/**
* Return the internal BeanFactory to be used for the specified bean.
* @param beanName the name of the target bean
* @return the internal BeanFactory to be used
*/
protected DefaultListableBeanFactory getInternalBeanFactoryForBean(String beanName) {
DefaultListableBeanFactory internalBeanFactory = null;
synchronized (this.internalBeanFactories) {
internalBeanFactory = (DefaultListableBeanFactory) this.internalBeanFactories.get(beanName);
if (internalBeanFactory == null) {
internalBeanFactory = buildInternalBeanFactory(this.beanFactory);
this.internalBeanFactories.put(beanName, internalBeanFactory);
}
}
return internalBeanFactory;
}
/**
* Build an internal BeanFactory for resolving target beans.
* @param containingFactory the containing BeanFactory that originally defines the beans
* @return an independent internal BeanFactory to hold copies of some target beans
*/
protected DefaultListableBeanFactory buildInternalBeanFactory(ConfigurableBeanFactory containingFactory) {
// Set parent so that references (up container hierarchies) are correctly resolved.
DefaultListableBeanFactory internalBeanFactory = new DefaultListableBeanFactory(containingFactory);
// Required so that all BeanPostProcessors, Scopes, etc become available.
internalBeanFactory.copyConfigurationFrom(containingFactory);
// Filter out BeanPostProcessors that are part of the AOP infrastructure,
// since those are only meant to apply to beans defined in the original factory.
for (Iterator it = internalBeanFactory.getBeanPostProcessors().iterator(); it.hasNext();) {
BeanPostProcessor postProcessor = (BeanPostProcessor) it.next();
if (postProcessor instanceof AopInfrastructureBean) {
it.remove();
}
}
return internalBeanFactory;
}
/**
* Destroys the internal BeanFactory on shutdown of the TargetSourceCreator.
* @see #getInternalBeanFactoryForBean
*/
public void destroy() {
synchronized (this.internalBeanFactories) {
for (Iterator it = this.internalBeanFactories.values().iterator(); it.hasNext();) {
((DefaultListableBeanFactory) it.next()).destroySingletons();
}
}
}
//---------------------------------------------------------------------
// Template methods to be implemented by subclasses
//---------------------------------------------------------------------
/**
* Return whether this TargetSourceCreator is prototype-based.
* The scope of the target bean definition will be set accordingly.
* <p>Default is "true".
* @see org.springframework.beans.factory.config.BeanDefinition#isSingleton()
*/
protected boolean isPrototypeBased() {
return true;
}
/**
* Subclasses must implement this method to return a new AbstractPrototypeBasedTargetSource
* if they wish to create a custom TargetSource for this bean, or <code>null</code> if they are
* not interested it in, in which case no special target source will be created.
* Subclasses should not call <code>setTargetBeanName</code> or <code>setBeanFactory</code>
* on the AbstractPrototypeBasedTargetSource: This class' implementation of
* <code>getTargetSource()</code> will do that.
* @param beanClass the class of the bean to create a TargetSource for
* @param beanName the name of the bean
* @return the AbstractPrototypeBasedTargetSource, or <code>null</code> if we don't match this
*/
protected abstract AbstractBeanFactoryBasedTargetSource createBeanFactoryBasedTargetSource(
Class beanClass, String beanName);
}