/*
* 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.resolver;
import static com.alibaba.citrus.util.Assert.*;
import com.alibaba.citrus.springext.support.SpringExtSchemaSet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.xml.BeanDefinitionParserDelegate;
import org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader;
import org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver;
import org.springframework.beans.factory.xml.NamespaceHandlerResolver;
import org.springframework.beans.factory.xml.ResourceEntityResolver;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.beans.factory.xml.XmlReaderContext;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.ResourceLoader;
import org.w3c.dom.Element;
import org.xml.sax.EntityResolver;
/**
* 用来处理<code>XmlBeanDefinitionReader</code>，添加configuration point的功能。
*
* @author Michael Zhou
*/
public class XmlBeanDefinitionReaderProcessor {
private final static String PROPERTY_SKIP_VALIDATION = "skipValidation";
private final static Logger log = LoggerFactory.getLogger(XmlBeanDefinitionReaderProcessor.class);
private final XmlBeanDefinitionReader reader;
private final boolean skipValidation;
public XmlBeanDefinitionReaderProcessor(XmlBeanDefinitionReader reader) {
this(reader, Boolean.getBoolean(PROPERTY_SKIP_VALIDATION));
}
public XmlBeanDefinitionReaderProcessor(XmlBeanDefinitionReader reader, boolean skipValidation) {
this.reader = assertNotNull(reader, "XmlBeanDefinitionReader");
this.skipValidation = skipValidation;
}
public void addConfigurationPointsSupport() {
if (skipValidation) {
reader.setValidationMode(XmlBeanDefinitionReader.VALIDATION_NONE);
reader.setNamespaceAware(true); // 为了添加Configuration Point支持，namespace是必须打开的。
reader.setDocumentReaderClass(DocumentReaderSkippingValidation.class); // 对beans中的参数提供默认值
log.warn(
"XSD validation has been disabled according to the system property: -D{}. Please be warned: NEVER skipping validation in Production Environment.",
PROPERTY_SKIP_VALIDATION);
}
ResourceLoader resourceLoader = reader.getResourceLoader();
if (resourceLoader == null) {
resourceLoader = new DefaultResourceLoader();
}
ClassLoader classLoader = resourceLoader.getClassLoader();
// schema providers
SpringExtSchemaSet schemas = new SpringExtSchemaSet(classLoader);
// default resolvers
EntityResolver defaultEntityResolver = new ResourceEntityResolver(resourceLoader);
NamespaceHandlerResolver defaultNamespaceHandlerResolver = new DefaultNamespaceHandlerResolver(classLoader);
// new resolvers
EntityResolver entityResolver = new SchemaEntityResolver(defaultEntityResolver, schemas);
NamespaceHandlerResolver namespaceHandlerResolver = new ConfigurationPointNamespaceHandlerResolver(schemas.getConfigurationPoints(), defaultNamespaceHandlerResolver);
reader.setEntityResolver(entityResolver);
reader.setNamespaceHandlerResolver(namespaceHandlerResolver);
}
/**
* 在有schema验证的情况下，部分attribute的默认值是由schema提供的。当没有schema验证时，这些默认值便不复存在，
* 这导致spring的行为在<code>-DskipValidation</code>
* 时和原来不同。本类继承了spring的原有类，但对缺失的默认值提供明确的值。
*/
public static class DocumentReaderSkippingValidation extends DefaultBeanDefinitionDocumentReader {
@Override
protected BeanDefinitionParserDelegate createHelper(XmlReaderContext readerContext, Element root) {
BeanDefinitionParserDelegate delegate = new BeanDefinitionParserDelegateSkippingValidation(readerContext);
delegate.initDefaults(root);
return delegate;
}
}
private static class BeanDefinitionParserDelegateSkippingValidation extends BeanDefinitionParserDelegate {
public BeanDefinitionParserDelegateSkippingValidation(XmlReaderContext readerContext) {
super(readerContext);
}
@Override
public AbstractBeanDefinition parseBeanDefinitionAttributes(Element ele, String beanName,
BeanDefinition containingBean,
AbstractBeanDefinition bd) {
setDefaultValueForAttribute(ele, LAZY_INIT_ATTRIBUTE, DEFAULT_VALUE);
setDefaultValueForAttribute(ele, AUTOWIRE_ATTRIBUTE, DEFAULT_VALUE);
setDefaultValueForAttribute(ele, DEPENDENCY_CHECK_ATTRIBUTE, DEFAULT_VALUE);
setDefaultValueForAttribute(ele, AUTOWIRE_CANDIDATE_ATTRIBUTE, DEFAULT_VALUE);
return super.parseBeanDefinitionAttributes(ele, beanName, containingBean, bd);
}
@Override
public void parseQualifierElement(Element ele, AbstractBeanDefinition bd) {
setDefaultValueForAttribute(ele, TYPE_ATTRIBUTE, Qualifier.class.getName());
super.parseQualifierElement(ele, bd);
}
private void setDefaultValueForAttribute(Element ele, String attrName, String defaultValue) {
if (!ele.hasAttribute(attrName)) {
ele.setAttribute(attrName, defaultValue);
}
}
}
}