/*
* 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.context.annotation;
import java.lang.annotation.Annotation;
import java.util.Iterator;
import java.util.Set;
import java.util.regex.Pattern;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.FatalBeanException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.parsing.BeanComponentDefinition;
import org.springframework.beans.factory.parsing.CompositeComponentDefinition;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.beans.factory.xml.BeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.beans.factory.xml.XmlReaderContext;
import org.springframework.core.type.filter.AnnotationTypeFilter;
import org.springframework.core.type.filter.AspectJTypeFilter;
import org.springframework.core.type.filter.AssignableTypeFilter;
import org.springframework.core.type.filter.RegexPatternTypeFilter;
import org.springframework.core.type.filter.TypeFilter;
import org.springframework.util.StringUtils;
/**
* Parser for the <context:component-scan/> element.
*
* @author Mark Fisher
* @author Ramnivas Laddad
* @author Juergen Hoeller
* @since 2.5
*/
public class ComponentScanBeanDefinitionParser implements BeanDefinitionParser {
private static final String BASE_PACKAGE_ATTRIBUTE = "base-package";
private static final String RESOURCE_PATTERN_ATTRIBUTE = "resource-pattern";
private static final String USE_DEFAULT_FILTERS_ATTRIBUTE = "use-default-filters";
private static final String ANNOTATION_CONFIG_ATTRIBUTE = "annotation-config";
private static final String NAME_GENERATOR_ATTRIBUTE = "name-generator";
private static final String SCOPE_RESOLVER_ATTRIBUTE = "scope-resolver";
private static final String SCOPED_PROXY_ATTRIBUTE = "scoped-proxy";
private static final String EXCLUDE_FILTER_ELEMENT = "exclude-filter";
private static final String INCLUDE_FILTER_ELEMENT = "include-filter";
private static final String FILTER_TYPE_ATTRIBUTE = "type";
private static final String FILTER_EXPRESSION_ATTRIBUTE = "expression";
public BeanDefinition parse(Element element, ParserContext parserContext) {
String[] basePackages =
StringUtils.commaDelimitedListToStringArray(element.getAttribute(BASE_PACKAGE_ATTRIBUTE));
// Actually scan for bean definitions and register them.
ClassPathBeanDefinitionScanner scanner = configureScanner(parserContext, element);
Set<BeanDefinitionHolder> beanDefinitions = scanner.doScan(basePackages);
registerComponents(parserContext.getReaderContext(), beanDefinitions, element);
return null;
}
protected ClassPathBeanDefinitionScanner configureScanner(ParserContext parserContext, Element element) {
XmlReaderContext readerContext = parserContext.getReaderContext();
boolean useDefaultFilters = true;
if (element.hasAttribute(USE_DEFAULT_FILTERS_ATTRIBUTE)) {
useDefaultFilters = Boolean.valueOf(element.getAttribute(USE_DEFAULT_FILTERS_ATTRIBUTE));
}
// Delegate bean definition registration to scanner class.
ClassPathBeanDefinitionScanner scanner = createScanner(readerContext, useDefaultFilters);
scanner.setResourceLoader(readerContext.getResourceLoader());
scanner.setBeanDefinitionDefaults(parserContext.getDelegate().getBeanDefinitionDefaults());
scanner.setAutowireCandidatePatterns(parserContext.getDelegate().getAutowireCandidatePatterns());
if (element.hasAttribute(RESOURCE_PATTERN_ATTRIBUTE)) {
scanner.setResourcePattern(element.getAttribute(RESOURCE_PATTERN_ATTRIBUTE));
}
try {
parseBeanNameGenerator(element, scanner);
}
catch (Exception ex) {
readerContext.error(ex.getMessage(), readerContext.extractSource(element), ex.getCause());
}
try {
parseScope(element, scanner);
}
catch (Exception ex) {
readerContext.error(ex.getMessage(), readerContext.extractSource(element), ex.getCause());
}
parseTypeFilters(element, scanner, readerContext);
return scanner;
}
protected ClassPathBeanDefinitionScanner createScanner(XmlReaderContext readerContext, boolean useDefaultFilters) {
return new ClassPathBeanDefinitionScanner(readerContext.getRegistry(), useDefaultFilters);
}
protected void registerComponents(
XmlReaderContext readerContext, Set<BeanDefinitionHolder> beanDefinitions, Element element) {
Object source = readerContext.extractSource(element);
CompositeComponentDefinition compositeDef = new CompositeComponentDefinition(element.getTagName(), source);
for (Iterator it = beanDefinitions.iterator(); it.hasNext();) {
BeanDefinitionHolder beanDefHolder = (BeanDefinitionHolder) it.next();
compositeDef.addNestedComponent(new BeanComponentDefinition(beanDefHolder));
}
// Register annotation config processors, if necessary.
boolean annotationConfig = true;
if (element.hasAttribute(ANNOTATION_CONFIG_ATTRIBUTE)) {
annotationConfig = Boolean.valueOf(element.getAttribute(ANNOTATION_CONFIG_ATTRIBUTE));
}
if (annotationConfig) {
Set<BeanDefinitionHolder> processorDefinitions =
AnnotationConfigUtils.registerAnnotationConfigProcessors(readerContext.getRegistry(), source);
for (BeanDefinitionHolder processorDefinition : processorDefinitions) {
compositeDef.addNestedComponent(new BeanComponentDefinition(processorDefinition));
}
}
readerContext.fireComponentRegistered(compositeDef);
}
protected void parseBeanNameGenerator(Element element, ClassPathBeanDefinitionScanner scanner) {
if (element.hasAttribute(NAME_GENERATOR_ATTRIBUTE)) {
BeanNameGenerator beanNameGenerator = (BeanNameGenerator) instantiateUserDefinedStrategy(
element.getAttribute(NAME_GENERATOR_ATTRIBUTE), BeanNameGenerator.class,
scanner.getResourceLoader().getClassLoader());
scanner.setBeanNameGenerator(beanNameGenerator);
}
}
protected void parseScope(Element element, ClassPathBeanDefinitionScanner scanner) {
// Register ScopeMetadataResolver if class name provided.
if (element.hasAttribute(SCOPE_RESOLVER_ATTRIBUTE)) {
if (element.hasAttribute(SCOPED_PROXY_ATTRIBUTE)) {
throw new IllegalArgumentException(
"Cannot define both 'scope-resolver' and 'scoped-proxy' on <component-scan> tag");
}
ScopeMetadataResolver scopeMetadataResolver = (ScopeMetadataResolver) instantiateUserDefinedStrategy(
element.getAttribute(SCOPE_RESOLVER_ATTRIBUTE), ScopeMetadataResolver.class,
scanner.getResourceLoader().getClassLoader());
scanner.setScopeMetadataResolver(scopeMetadataResolver);
}
if (element.hasAttribute(SCOPED_PROXY_ATTRIBUTE)) {
String mode = element.getAttribute(SCOPED_PROXY_ATTRIBUTE);
if ("targetClass".equals(mode)) {
scanner.setScopedProxyMode(ScopedProxyMode.TARGET_CLASS);
}
else if ("interfaces".equals(mode)) {
scanner.setScopedProxyMode(ScopedProxyMode.INTERFACES);
}
else if ("no".equals(mode)) {
scanner.setScopedProxyMode(ScopedProxyMode.NO);
}
else {
throw new IllegalArgumentException("scoped-proxy only supports 'no', 'interfaces' and 'targetClass'");
}
}
}
protected void parseTypeFilters(
Element element, ClassPathBeanDefinitionScanner scanner, XmlReaderContext readerContext) {
// Parse exclude and include filter elements.
ClassLoader classLoader = scanner.getResourceLoader().getClassLoader();
NodeList nodeList = element.getChildNodes();
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
String localName = node.getLocalName();
try {
if (INCLUDE_FILTER_ELEMENT.equals(localName)) {
TypeFilter typeFilter = createTypeFilter((Element) node, classLoader);
scanner.addIncludeFilter(typeFilter);
}
else if (EXCLUDE_FILTER_ELEMENT.equals(localName)) {
TypeFilter typeFilter = createTypeFilter((Element) node, classLoader);
scanner.addExcludeFilter(typeFilter);
}
}
catch (Exception ex) {
readerContext.error(ex.getMessage(), readerContext.extractSource(element), ex.getCause());
}
}
}
}
@SuppressWarnings("unchecked")
protected TypeFilter createTypeFilter(Element element, ClassLoader classLoader) {
String filterType = element.getAttribute(FILTER_TYPE_ATTRIBUTE);
String expression = element.getAttribute(FILTER_EXPRESSION_ATTRIBUTE);
try {
if ("annotation".equals(filterType)) {
return new AnnotationTypeFilter((Class<Annotation>) classLoader.loadClass(expression));
}
else if ("assignable".equals(filterType)) {
return new AssignableTypeFilter(classLoader.loadClass(expression));
}
else if ("aspectj".equals(filterType)) {
return new AspectJTypeFilter(expression, classLoader);
}
else if ("regex".equals(filterType)) {
return new RegexPatternTypeFilter(Pattern.compile(expression));
}
else if ("custom".equals(filterType)) {
Class filterClass = classLoader.loadClass(expression);
if (!TypeFilter.class.isAssignableFrom(filterClass)) {
throw new IllegalArgumentException(
"Class is not assignable to [" + TypeFilter.class.getName() + "]: " + expression);
}
return (TypeFilter) BeanUtils.instantiateClass(filterClass);
}
else {
throw new IllegalArgumentException("Unsupported filter type: " + filterType);
}
}
catch (ClassNotFoundException ex) {
throw new FatalBeanException("Type filter class not found: " + expression, ex);
}
}
@SuppressWarnings("unchecked")
private Object instantiateUserDefinedStrategy(String className, Class strategyType, ClassLoader classLoader) {
Object result = null;
try {
result = classLoader.loadClass(className).newInstance();
}
catch (ClassNotFoundException ex) {
throw new IllegalArgumentException("Class [" + className + "] for strategy [" +
strategyType.getName() + "] not found", ex);
}
catch (Exception ex) {
throw new IllegalArgumentException("Unable to instantiate class [" + className + "] for strategy [" +
strategyType.getName() + "]. A zero-argument constructor is required", ex);
}
if (!strategyType.isAssignableFrom(result.getClass())) {
throw new IllegalArgumentException("Provided class name must be an implementation of " + strategyType);
}
return result;
}
}