/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.citrus.springext.support.parser;
import static com.alibaba.citrus.springext.util.SpringExtUtil.*;
import static com.alibaba.citrus.util.StringUtil.*;
import static org.springframework.beans.factory.config.BeanDefinition.*;
import com.alibaba.citrus.springext.support.parser.NamedBeanDefinitionParserMixin.DefaultNameBDParser;
import com.alibaba.citrus.springext.util.ProxyTargetFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.xml.AbstractBeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.ResourceLoader;
import org.w3c.dom.Element;
/**
* 用来创建proxy的parser。
*
* @author Michael Zhou
*/
public abstract class AbstractNamedProxyBeanDefinitionParser extends AbstractBeanDefinitionParser implements
DefaultNameBDParser {
private final NamedBeanDefinitionParserMixin mixin = new NamedBeanDefinitionParserMixin(this);
/**
* 取得bean的默认名称。
* <p>
* 可以注册多个默认名，以逗号或空格分开。第二名名称及其后的名称，将被注册成别名。
* </p>
*/
protected abstract String getDefaultName();
/** 从id attribute中取得bean name，假如未指定，则从<code>getDefaultName()</code>中取得默认名。 */
@Override
protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext) {
return mixin.resolveId(element, definition, parserContext);
}
/** 假如当前bean name为默认名，则同时注册默认的aliases。 */
@Override
protected void registerBeanDefinition(BeanDefinitionHolder definition, BeanDefinitionRegistry registry) {
mixin.registerBeanDefinition(definition, registry);
}
public final String internal_getDefaultName() {
return getDefaultName();
}
public void super_registerBeanDefinition(BeanDefinitionHolder definition, BeanDefinitionRegistry registry) {
super.registerBeanDefinition(definition, registry);
}
@Override
protected final AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
BeanDefinitionBuilder proxyBuilder = BeanDefinitionBuilder.genericBeanDefinition(ProxyFactoryBean.class);
AbstractBeanDefinitionParser realParser = getRealObjectParser();
// 取得真实的bean，注意，由于设置了containingBean=proxyBean，这个bean不会被注册到registry
ParserContext realBeanParserContext = new ParserContext(parserContext.getReaderContext(),
parserContext.getDelegate(), proxyBuilder.getRawBeanDefinition());
AbstractBeanDefinition realBd = (AbstractBeanDefinition) realParser.parse(element, realBeanParserContext);
// 检查scope，对于singleton和prototype，不创建proxy，直接返回真实的bean，否则创建proxy bean
String scope = trimToNull(getScope(element, realBd));
if (scope == null || scope.equalsIgnoreCase(SCOPE_SINGLETON) || scope.equalsIgnoreCase(SCOPE_PROTOTYPE)) {
return realBd;
} else {
realBd.setScope(scope);
// 禁止autowire注入这个实际bean。
realBd.setAutowireCandidate(false);
// 将原始bean注册成proxyTarget.*
String targetBeanName = "proxyTarget." + resolveId(element, realBd, parserContext);
registerBeanDefinition(new BeanDefinitionHolder(realBd, targetBeanName), parserContext.getRegistry());
// 创建proxy bean
proxyBuilder.addConstructorArgValue(getProxyInterface(element));
proxyBuilder.addConstructorArgValue(targetBeanName);
return proxyBuilder.getBeanDefinition();
}
}
protected abstract Class<?> getProxyInterface(Element element);
protected String getScope(Element element, AbstractBeanDefinition realBd) {
return element.getAttribute("scope");
}
protected abstract AbstractBeanDefinitionParser getRealObjectParser();
public static class ProxyFactoryBean implements FactoryBean, BeanFactoryAware, ResourceLoaderAware {
private final Class<?> targetBeanType;
private final String targetBeanName;
private BeanFactory factory;
private ClassLoader loader;
public ProxyFactoryBean(Class<?> targetBeanType, String targetBeanName) {
this.targetBeanType = targetBeanType;
this.targetBeanName = targetBeanName;
}
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
this.factory = beanFactory;
}
public void setResourceLoader(ResourceLoader resourceLoader) {
this.loader = resourceLoader.getClassLoader();
}
public Class<?> getObjectType() {
return targetBeanType;
}
public boolean isSingleton() {
return true;
}
public Object getObject() throws Exception {
return createProxy(targetBeanType, loader, new ProxyTargetFactoryImpl(targetBeanName, factory));
}
}
private static class ProxyTargetFactoryImpl implements ProxyTargetFactory {
private final String targetBeanName;
private final BeanFactory factory;
public ProxyTargetFactoryImpl(String targetBeanName, BeanFactory factory) {
this.targetBeanName = targetBeanName;
this.factory = factory;
}
public Object getObject() {
return factory.getBean(targetBeanName);
}
}
}