/*
* 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.scope;
import java.lang.reflect.Modifier;
import org.springframework.aop.framework.AopInfrastructureBean;
import org.springframework.aop.framework.ProxyConfig;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.aop.support.DelegatingIntroductionInterceptor;
import org.springframework.aop.target.SimpleBeanTargetSource;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.FactoryBeanNotInitializedException;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.util.ClassUtils;
/**
* Convenient proxy factory bean for scoped objects.
*
* <p>Proxies created using this factory bean are thread-safe singletons
* and may be injected into shared objects, with transparent scoping behavior.
*
* <p>Proxies returned by this class implement the {@link ScopedObject} interface.
* This presently allows for removing the corresponding object from the scope,
* seamlessly creating a new instance in the scope on next access.
*
* <p>Please note that the proxies created by this factory are
* <i>class-based</i> proxies by default. This can be customized
* through switching the "proxyTargetClass" property to "false".
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since 2.0
* @see #setProxyTargetClass
*/
public class ScopedProxyFactoryBean extends ProxyConfig implements FactoryBean<Object>, BeanFactoryAware {
/** The TargetSource that manages scoping */
private final SimpleBeanTargetSource scopedTargetSource = new SimpleBeanTargetSource();
/** The name of the target bean */
private String targetBeanName;
/** The cached singleton proxy */
private Object proxy;
/**
* Create a new ScopedProxyFactoryBean instance.
*/
public ScopedProxyFactoryBean() {
setProxyTargetClass(true);
}
/**
* Set the name of the bean that is to be scoped.
*/
public void setTargetBeanName(String targetBeanName) {
this.targetBeanName = targetBeanName;
this.scopedTargetSource.setTargetBeanName(targetBeanName);
}
public void setBeanFactory(BeanFactory beanFactory) {
if (!(beanFactory instanceof ConfigurableBeanFactory)) {
throw new IllegalStateException("Not running in a ConfigurableBeanFactory: " + beanFactory);
}
ConfigurableBeanFactory cbf = (ConfigurableBeanFactory) beanFactory;
this.scopedTargetSource.setBeanFactory(beanFactory);
ProxyFactory pf = new ProxyFactory();
pf.copyFrom(this);
pf.setTargetSource(this.scopedTargetSource);
Class beanType = beanFactory.getType(this.targetBeanName);
if (beanType == null) {
throw new IllegalStateException("Cannot create scoped proxy for bean '" + this.targetBeanName +
"': Target type could not be determined at the time of proxy creation.");
}
if (!isProxyTargetClass() || beanType.isInterface() || Modifier.isPrivate(beanType.getModifiers())) {
pf.setInterfaces(ClassUtils.getAllInterfacesForClass(beanType, cbf.getBeanClassLoader()));
}
// Add an introduction that implements only the methods on ScopedObject.
ScopedObject scopedObject = new DefaultScopedObject(cbf, this.scopedTargetSource.getTargetBeanName());
pf.addAdvice(new DelegatingIntroductionInterceptor(scopedObject));
// Add the AopInfrastructureBean marker to indicate that the scoped proxy
// itself is not subject to auto-proxying! Only its target bean is.
pf.addInterface(AopInfrastructureBean.class);
this.proxy = pf.getProxy(cbf.getBeanClassLoader());
}
public Object getObject() {
if (this.proxy == null) {
throw new FactoryBeanNotInitializedException();
}
return this.proxy;
}
public Class<?> getObjectType() {
if (this.proxy != null) {
return this.proxy.getClass();
}
if (this.scopedTargetSource != null) {
return this.scopedTargetSource.getTargetClass();
}
return null;
}
public boolean isSingleton() {
return true;
}
}
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