/*
* Copyright 2002-2010 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.io.IOException;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.parsing.FailFastProblemReporter;
import org.springframework.beans.factory.parsing.PassThroughSourceExtractor;
import org.springframework.beans.factory.parsing.ProblemReporter;
import org.springframework.beans.factory.parsing.SourceExtractor;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.core.Ordered;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
/**
* {@link BeanFactoryPostProcessor} used for bootstrapping processing of
* {@link Configuration @Configuration} classes.
*
* <p>Registered by default when using {@literal <context:annotation-config/>} or
* {@literal <context:component-scan/>}. Otherwise, may be declared manually as
* with any other BeanFactoryPostProcessor.
*
* <p>This post processor is {@link Ordered#HIGHEST_PRECEDENCE} as it is important
* that any {@link Bean} methods declared in Configuration classes have their
* respective bean definitions registered before any other BeanFactoryPostProcessor
* executes.
*
* @author Chris Beams
* @author Juergen Hoeller
* @since 3.0
*/
public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPostProcessor, BeanClassLoaderAware {
/** Whether the CGLIB2 library is present on the classpath */
private static final boolean cglibAvailable = ClassUtils.isPresent(
"net.sf.cglib.proxy.Enhancer", ConfigurationClassPostProcessor.class.getClassLoader());
private final Log logger = LogFactory.getLog(getClass());
private SourceExtractor sourceExtractor = new PassThroughSourceExtractor();
private ProblemReporter problemReporter = new FailFastProblemReporter();
private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
private MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory();
private boolean setMetadataReaderFactoryCalled = false;
private boolean postProcessBeanDefinitionRegistryCalled = false;
private boolean postProcessBeanFactoryCalled = false;
/**
* Set the {@link SourceExtractor} to use for generated bean definitions
* that correspond to {@link Bean} factory methods.
*/
public void setSourceExtractor(SourceExtractor sourceExtractor) {
this.sourceExtractor = (sourceExtractor != null ? sourceExtractor : new PassThroughSourceExtractor());
}
/**
* Set the {@link ProblemReporter} to use.
* <p>Used to register any problems detected with {@link Configuration} or {@link Bean}
* declarations. For instance, an @Bean method marked as {@literal final} is illegal
* and would be reported as a problem. Defaults to {@link FailFastProblemReporter}.
*/
public void setProblemReporter(ProblemReporter problemReporter) {
this.problemReporter = (problemReporter != null ? problemReporter : new FailFastProblemReporter());
}
/**
* Set the {@link MetadataReaderFactory} to use.
* <p>Default is a {@link CachingMetadataReaderFactory} for the specified
* {@link #setBeanClassLoader bean class loader}.
*/
public void setMetadataReaderFactory(MetadataReaderFactory metadataReaderFactory) {
Assert.notNull(metadataReaderFactory, "MetadataReaderFactory must not be null");
this.metadataReaderFactory = metadataReaderFactory;
this.setMetadataReaderFactoryCalled = true;
}
public void setBeanClassLoader(ClassLoader beanClassLoader) {
this.beanClassLoader = beanClassLoader;
if (!this.setMetadataReaderFactoryCalled) {
this.metadataReaderFactory = new CachingMetadataReaderFactory(beanClassLoader);
}
}
public int getOrder() {
return Ordered.HIGHEST_PRECEDENCE;
}
/**
* Derive further bean definitions from the configuration classes in the registry.
*/
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
if (this.postProcessBeanDefinitionRegistryCalled) {
throw new IllegalStateException(
"postProcessBeanDefinitionRegistry already called for this post-processor");
}
if (this.postProcessBeanFactoryCalled) {
throw new IllegalStateException(
"postProcessBeanFactory already called for this post-processor");
}
this.postProcessBeanDefinitionRegistryCalled = true;
processConfigBeanDefinitions(registry);
}
/**
* Prepare the Configuration classes for servicing bean requests at runtime
* by replacing them with CGLIB-enhanced subclasses.
*/
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
if (this.postProcessBeanFactoryCalled) {
throw new IllegalStateException(
"postProcessBeanFactory already called for this post-processor");
}
this.postProcessBeanFactoryCalled = true;
if (!this.postProcessBeanDefinitionRegistryCalled) {
// BeanDefinitionRegistryPostProcessor hook apparently not supported...
// Simply call processConfigBeanDefinitions lazily at this point then.
processConfigBeanDefinitions((BeanDefinitionRegistry) beanFactory);
}
enhanceConfigurationClasses(beanFactory);
}
/**
* Build and validate a configuration model based on the registry of
* {@link Configuration} classes.
*/
public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
Set<BeanDefinitionHolder> configCandidates = new LinkedHashSet<BeanDefinitionHolder>();
for (String beanName : registry.getBeanDefinitionNames()) {
BeanDefinition beanDef = registry.getBeanDefinition(beanName);
if (ConfigurationClassBeanDefinitionReader.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
}
}
// Return immediately if no @Configuration classes were found
if (configCandidates.isEmpty()) {
return;
}
// Populate a new configuration model by parsing each @Configuration classes
ConfigurationClassParser parser = new ConfigurationClassParser(this.metadataReaderFactory, this.problemReporter);
for (BeanDefinitionHolder holder : configCandidates) {
BeanDefinition bd = holder.getBeanDefinition();
try {
if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
parser.parse(((AbstractBeanDefinition) bd).getBeanClass(), holder.getBeanName());
}
else {
parser.parse(bd.getBeanClassName(), holder.getBeanName());
}
}
catch (IOException ex) {
throw new BeanDefinitionStoreException("Failed to load bean class: " + bd.getBeanClassName(), ex);
}
}
parser.validate();
// Read the model and create bean definitions based on its content
ConfigurationClassBeanDefinitionReader reader = new ConfigurationClassBeanDefinitionReader(
registry, this.sourceExtractor, this.problemReporter, this.metadataReaderFactory);
reader.loadBeanDefinitions(parser.getConfigurationClasses());
}
/**
* Post-processes a BeanFactory in search of Configuration class BeanDefinitions;
* any candidates are then enhanced by a {@link ConfigurationClassEnhancer}.
* Candidate status is determined by BeanDefinition attribute metadata.
* @see ConfigurationClassEnhancer
*/
public void enhanceConfigurationClasses(ConfigurableListableBeanFactory beanFactory) {
Map<String, AbstractBeanDefinition> configBeanDefs = new LinkedHashMap<String, AbstractBeanDefinition>();
for (String beanName : beanFactory.getBeanDefinitionNames()) {
BeanDefinition beanDef = beanFactory.getBeanDefinition(beanName);
if (ConfigurationClassBeanDefinitionReader.isFullConfigurationClass(beanDef)) {
if (!(beanDef instanceof AbstractBeanDefinition)) {
throw new BeanDefinitionStoreException("Cannot enhance @Configuration bean definition '" +
beanName + "' since it is not stored in an AbstractBeanDefinition subclass");
}
configBeanDefs.put(beanName, (AbstractBeanDefinition) beanDef);
}
}
if (configBeanDefs.isEmpty()) {
// nothing to enhance -> return immediately
return;
}
if (!cglibAvailable) {
throw new IllegalStateException("CGLIB is required to process @Configuration classes. " +
"Either add CGLIB to the classpath or remove the following @Configuration bean definitions: " +
configBeanDefs.keySet());
}
ConfigurationClassEnhancer enhancer = new ConfigurationClassEnhancer(beanFactory);
for (Map.Entry<String, AbstractBeanDefinition> entry : configBeanDefs.entrySet()) {
AbstractBeanDefinition beanDef = entry.getValue();
try {
Class<?> configClass = beanDef.resolveBeanClass(this.beanClassLoader);
Class<?> enhancedClass = enhancer.enhance(configClass);
if (logger.isDebugEnabled()) {
logger.debug(String.format("Replacing bean definition '%s' existing class name '%s' " +
"with enhanced class name '%s'", entry.getKey(), configClass.getName(), enhancedClass.getName()));
}
beanDef.setBeanClass(enhancedClass);
}
catch (Throwable ex) {
throw new IllegalStateException("Cannot load configuration class: " + beanDef.getBeanClassName(), ex);
}
}
}
}