/*
* Copyright 2002-2017 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.FileNotFoundException;
import java.io.IOException;
import java.net.UnknownHostException;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.parsing.Location;
import org.springframework.beans.factory.parsing.Problem;
import org.springframework.beans.factory.parsing.ProblemReporter;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionReader;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.ConfigurationCondition.ConfigurationPhase;
import org.springframework.core.NestedIOException;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.core.env.CompositePropertySource;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.DefaultPropertySourceFactory;
import org.springframework.core.io.support.EncodedResource;
import org.springframework.core.io.support.PropertySourceFactory;
import org.springframework.core.io.support.ResourcePropertySource;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.MethodMetadata;
import org.springframework.core.type.StandardAnnotationMetadata;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.core.type.filter.AssignableTypeFilter;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;
/**
* Parses a {@link Configuration} class definition, populating a collection of
* {@link ConfigurationClass} objects (parsing a single Configuration class may result in
* any number of ConfigurationClass objects because one Configuration class may import
* another using the {@link Import} annotation).
*
* <p>This class helps separate the concern of parsing the structure of a Configuration
* class from the concern of registering BeanDefinition objects based on the
* content of that model (with the exception of {@code @ComponentScan} annotations which
* need to be registered immediately).
*
* <p>This ASM-based implementation avoids reflection and eager class loading in order to
* interoperate effectively with lazy class loading in a Spring ApplicationContext.
*
* @author Chris Beams
* @author Juergen Hoeller
* @author Phillip Webb
* @author Sam Brannen
* @since 3.0
* @see ConfigurationClassBeanDefinitionReader
*/
class ConfigurationClassParser {
private static final PropertySourceFactory DEFAULT_PROPERTY_SOURCE_FACTORY = new DefaultPropertySourceFactory();
private static final Comparator<DeferredImportSelectorHolder> DEFERRED_IMPORT_COMPARATOR =
new Comparator<ConfigurationClassParser.DeferredImportSelectorHolder>() {
@Override
public int compare(DeferredImportSelectorHolder o1, DeferredImportSelectorHolder o2) {
return AnnotationAwareOrderComparator.INSTANCE.compare(o1.getImportSelector(), o2.getImportSelector());
}
};
private final Log logger = LogFactory.getLog(getClass());
private final MetadataReaderFactory metadataReaderFactory;
private final ProblemReporter problemReporter;
private final Environment environment;
private final ResourceLoader resourceLoader;
private final BeanDefinitionRegistry registry;
private final ComponentScanAnnotationParser componentScanParser;
private final ConditionEvaluator conditionEvaluator;
private final Map<ConfigurationClass, ConfigurationClass> configurationClasses =
new LinkedHashMap<ConfigurationClass, ConfigurationClass>();
private final Map<String, ConfigurationClass> knownSuperclasses = new HashMap<String, ConfigurationClass>();
private final List<String> propertySourceNames = new ArrayList<String>();
private final ImportStack importStack = new ImportStack();
private List<DeferredImportSelectorHolder> deferredImportSelectors;
/**
* Create a new {@link ConfigurationClassParser} instance that will be used
* to populate the set of configuration classes.
*/
public ConfigurationClassParser(MetadataReaderFactory metadataReaderFactory,
ProblemReporter problemReporter, Environment environment, ResourceLoader resourceLoader,
BeanNameGenerator componentScanBeanNameGenerator, BeanDefinitionRegistry registry) {
this.metadataReaderFactory = metadataReaderFactory;
this.problemReporter = problemReporter;
this.environment = environment;
this.resourceLoader = resourceLoader;
this.registry = registry;
this.componentScanParser = new ComponentScanAnnotationParser(
environment, resourceLoader, componentScanBeanNameGenerator, registry);
this.conditionEvaluator = new ConditionEvaluator(registry, environment, resourceLoader);
}
public void parse(Set<BeanDefinitionHolder> configCandidates) {
this.deferredImportSelectors = new LinkedList<DeferredImportSelectorHolder>();
for (BeanDefinitionHolder holder : configCandidates) {
BeanDefinition bd = holder.getBeanDefinition();
try {
if (bd instanceof AnnotatedBeanDefinition) {
parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName());
}
else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
parse(((AbstractBeanDefinition) bd).getBeanClass(), holder.getBeanName());
}
else {
parse(bd.getBeanClassName(), holder.getBeanName());
}
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to parse configuration class [" + bd.getBeanClassName() + "]", ex);
}
}
processDeferredImportSelectors();
}
protected final void parse(String className, String beanName) throws IOException {
MetadataReader reader = this.metadataReaderFactory.getMetadataReader(className);
processConfigurationClass(new ConfigurationClass(reader, beanName));
}
protected final void parse(Class<?> clazz, String beanName) throws IOException {
processConfigurationClass(new ConfigurationClass(clazz, beanName));
}
protected final void parse(AnnotationMetadata metadata, String beanName) throws IOException {
processConfigurationClass(new ConfigurationClass(metadata, beanName));
}
/**
* Validate each {@link ConfigurationClass} object.
* @see ConfigurationClass#validate
*/
public void validate() {
for (ConfigurationClass configClass : this.configurationClasses.keySet()) {
configClass.validate(this.problemReporter);
}
}
public Set<ConfigurationClass> getConfigurationClasses() {
return this.configurationClasses.keySet();
}
protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) {
return;
}
ConfigurationClass existingClass = this.configurationClasses.get(configClass);
if (existingClass != null) {
if (configClass.isImported()) {
if (existingClass.isImported()) {
existingClass.mergeImportedBy(configClass);
}
// Otherwise ignore new imported config class; existing non-imported class overrides it.
return;
}
else {
// Explicit bean definition found, probably replacing an import.
// Let's remove the old one and go with the new one.
this.configurationClasses.remove(configClass);
for (Iterator<ConfigurationClass> it = this.knownSuperclasses.values().iterator(); it.hasNext();) {
if (configClass.equals(it.next())) {
it.remove();
}
}
}
}
// Recursively process the configuration class and its superclass hierarchy.
SourceClass sourceClass = asSourceClass(configClass);
do {
sourceClass = doProcessConfigurationClass(configClass, sourceClass);
}
while (sourceClass != null);
this.configurationClasses.put(configClass, configClass);
}
/**
* Apply processing and build a complete {@link ConfigurationClass} by reading the
* annotations, members and methods from the source class. This method can be called
* multiple times as relevant sources are discovered.
* @param configClass the configuration class being build
* @param sourceClass a source class
* @return the superclass, or {@code null} if none found or previously processed
*/
protected final SourceClass doProcessConfigurationClass(ConfigurationClass configClass, SourceClass sourceClass)
throws IOException {
// Recursively process any member (nested) classes first
processMemberClasses(configClass, sourceClass);
// Process any @PropertySource annotations
for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(
sourceClass.getMetadata(), PropertySources.class,
org.springframework.context.annotation.PropertySource.class)) {
if (this.environment instanceof ConfigurableEnvironment) {
processPropertySource(propertySource);
}
else {
logger.warn("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() +
"]. Reason: Environment must implement ConfigurableEnvironment");
}
}
// Process any @ComponentScan annotations
Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(
sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class);
if (!componentScans.isEmpty() &&
!this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
for (AnnotationAttributes componentScan : componentScans) {
// The config class is annotated with @ComponentScan -> perform the scan immediately
Set<BeanDefinitionHolder> scannedBeanDefinitions =
this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName());
// Check the set of scanned definitions for any further config classes and parse recursively if needed
for (BeanDefinitionHolder holder : scannedBeanDefinitions) {
if (ConfigurationClassUtils.checkConfigurationClassCandidate(
holder.getBeanDefinition(), this.metadataReaderFactory)) {
parse(holder.getBeanDefinition().getBeanClassName(), holder.getBeanName());
}
}
}
}
// Process any @Import annotations
processImports(configClass, sourceClass, getImports(sourceClass), true);
// Process any @ImportResource annotations
if (sourceClass.getMetadata().isAnnotated(ImportResource.class.getName())) {
AnnotationAttributes importResource =
AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class);
String[] resources = importResource.getStringArray("locations");
Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader");
for (String resource : resources) {
String resolvedResource = this.environment.resolveRequiredPlaceholders(resource);
configClass.addImportedResource(resolvedResource, readerClass);
}
}
// Process individual @Bean methods
Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(sourceClass);
for (MethodMetadata methodMetadata : beanMethods) {
configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass));
}
// Process default methods on interfaces
processInterfaces(configClass, sourceClass);
// Process superclass, if any
if (sourceClass.getMetadata().hasSuperClass()) {
String superclass = sourceClass.getMetadata().getSuperClassName();
if (!superclass.startsWith("java") && !this.knownSuperclasses.containsKey(superclass)) {
this.knownSuperclasses.put(superclass, configClass);
// Superclass found, return its annotation metadata and recurse
return sourceClass.getSuperClass();
}
}
// No superclass -> processing is complete
return null;
}
/**
* Register member (nested) classes that happen to be configuration classes themselves.
*/
private void processMemberClasses(ConfigurationClass configClass, SourceClass sourceClass) throws IOException {
for (SourceClass memberClass : sourceClass.getMemberClasses()) {
if (ConfigurationClassUtils.isConfigurationCandidate(memberClass.getMetadata()) &&
!memberClass.getMetadata().getClassName().equals(configClass.getMetadata().getClassName())) {
if (this.importStack.contains(configClass)) {
this.problemReporter.error(new CircularImportProblem(configClass, this.importStack));
}
else {
this.importStack.push(configClass);
try {
processConfigurationClass(memberClass.asConfigClass(configClass));
}
finally {
this.importStack.pop();
}
}
}
}
}
/**
* Register default methods on interfaces implemented by the configuration class.
*/
private void processInterfaces(ConfigurationClass configClass, SourceClass sourceClass) throws IOException {
for (SourceClass ifc : sourceClass.getInterfaces()) {
Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(ifc);
for (MethodMetadata methodMetadata : beanMethods) {
if (!methodMetadata.isAbstract()) {
// A default method or other concrete method on a Java 8+ interface...
configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass));
}
}
processInterfaces(configClass, ifc);
}
}
/**
* Retrieve the metadata for all <code>@Bean</code> methods.
*/
private Set<MethodMetadata> retrieveBeanMethodMetadata(SourceClass sourceClass) {
AnnotationMetadata original = sourceClass.getMetadata();
Set<MethodMetadata> beanMethods = original.getAnnotatedMethods(Bean.class.getName());
if (beanMethods.size() > 1 && original instanceof StandardAnnotationMetadata) {
// Try reading the class file via ASM for deterministic declaration order...
// Unfortunately, the JVM's standard reflection returns methods in arbitrary
// order, even between different runs of the same application on the same JVM.
try {
AnnotationMetadata asm =
this.metadataReaderFactory.getMetadataReader(original.getClassName()).getAnnotationMetadata();
Set<MethodMetadata> asmMethods = asm.getAnnotatedMethods(Bean.class.getName());
if (asmMethods.size() >= beanMethods.size()) {
Set<MethodMetadata> selectedMethods = new LinkedHashSet<MethodMetadata>(asmMethods.size());
for (MethodMetadata asmMethod : asmMethods) {
for (MethodMetadata beanMethod : beanMethods) {
if (beanMethod.getMethodName().equals(asmMethod.getMethodName())) {
selectedMethods.add(beanMethod);
break;
}
}
}
if (selectedMethods.size() == beanMethods.size()) {
// All reflection-detected methods found in ASM method set -> proceed
beanMethods = selectedMethods;
}
}
}
catch (IOException ex) {
logger.debug("Failed to read class file via ASM for determining @Bean method order", ex);
// No worries, let's continue with the reflection metadata we started with...
}
}
return beanMethods;
}
/**
* Process the given <code>@PropertySource</code> annotation metadata.
* @param propertySource metadata for the <code>@PropertySource</code> annotation found
* @throws IOException if loading a property source failed
*/
private void processPropertySource(AnnotationAttributes propertySource) throws IOException {
String name = propertySource.getString("name");
if (!StringUtils.hasLength(name)) {
name = null;
}
String encoding = propertySource.getString("encoding");
if (!StringUtils.hasLength(encoding)) {
encoding = null;
}
String[] locations = propertySource.getStringArray("value");
Assert.isTrue(locations.length > 0, "At least one @PropertySource(value) location is required");
boolean ignoreResourceNotFound = propertySource.getBoolean("ignoreResourceNotFound");
Class<? extends PropertySourceFactory> factoryClass = propertySource.getClass("factory");
PropertySourceFactory factory = (factoryClass == PropertySourceFactory.class ?
DEFAULT_PROPERTY_SOURCE_FACTORY : BeanUtils.instantiateClass(factoryClass));
for (String location : locations) {
try {
String resolvedLocation = this.environment.resolveRequiredPlaceholders(location);
Resource resource = this.resourceLoader.getResource(resolvedLocation);
addPropertySource(factory.createPropertySource(name, new EncodedResource(resource, encoding)));
}
catch (IllegalArgumentException ex) {
// Placeholders not resolvable
if (ignoreResourceNotFound) {
if (logger.isInfoEnabled()) {
logger.info("Properties location [" + location + "] not resolvable: " + ex.getMessage());
}
}
else {
throw ex;
}
}
catch (IOException ex) {
// Resource not found when trying to open it
if (ignoreResourceNotFound &&
(ex instanceof FileNotFoundException || ex instanceof UnknownHostException)) {
if (logger.isInfoEnabled()) {
logger.info("Properties location [" + location + "] not resolvable: " + ex.getMessage());
}
}
else {
throw ex;
}
}
}
}
private void addPropertySource(PropertySource<?> propertySource) {
String name = propertySource.getName();
MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();
if (propertySources.contains(name) && this.propertySourceNames.contains(name)) {
// We've already added a version, we need to extend it
PropertySource<?> existing = propertySources.get(name);
PropertySource<?> newSource = (propertySource instanceof ResourcePropertySource ?
((ResourcePropertySource) propertySource).withResourceName() : propertySource);
if (existing instanceof CompositePropertySource) {
((CompositePropertySource) existing).addFirstPropertySource(newSource);
}
else {
if (existing instanceof ResourcePropertySource) {
existing = ((ResourcePropertySource) existing).withResourceName();
}
CompositePropertySource composite = new CompositePropertySource(name);
composite.addPropertySource(newSource);
composite.addPropertySource(existing);
propertySources.replace(name, composite);
}
}
else {
if (this.propertySourceNames.isEmpty()) {
propertySources.addLast(propertySource);
}
else {
String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
propertySources.addBefore(firstProcessed, propertySource);
}
}
this.propertySourceNames.add(name);
}
/**
* Returns {@code @Import} class, considering all meta-annotations.
*/
private Set<SourceClass> getImports(SourceClass sourceClass) throws IOException {
Set<SourceClass> imports = new LinkedHashSet<SourceClass>();
Set<SourceClass> visited = new LinkedHashSet<SourceClass>();
collectImports(sourceClass, imports, visited);
return imports;
}
/**
* Recursively collect all declared {@code @Import} values. Unlike most
* meta-annotations it is valid to have several {@code @Import}s declared with
* different values; the usual process of returning values from the first
* meta-annotation on a class is not sufficient.
* <p>For example, it is common for a {@code @Configuration} class to declare direct
* {@code @Import}s in addition to meta-imports originating from an {@code @Enable}
* annotation.
* @param sourceClass the class to search
* @param imports the imports collected so far
* @param visited used to track visited classes to prevent infinite recursion
* @throws IOException if there is any problem reading metadata from the named class
*/
private void collectImports(SourceClass sourceClass, Set<SourceClass> imports, Set<SourceClass> visited)
throws IOException {
if (visited.add(sourceClass)) {
for (SourceClass annotation : sourceClass.getAnnotations()) {
String annName = annotation.getMetadata().getClassName();
if (!annName.startsWith("java") && !annName.equals(Import.class.getName())) {
collectImports(annotation, imports, visited);
}
}
imports.addAll(sourceClass.getAnnotationAttributes(Import.class.getName(), "value"));
}
}
⭐️processDeferredImportSelectors
private void processDeferredImportSelectors() {
List<DeferredImportSelectorHolder> deferredImports = this.deferredImportSelectors;
this.deferredImportSelectors = null;
Collections.sort(deferredImports, DEFERRED_IMPORT_COMPARATOR);
for (DeferredImportSelectorHolder deferredImport : deferredImports) {
ConfigurationClass configClass = deferredImport.getConfigurationClass();
try {
//1 SpringBoot中:
// deferredImport.getImportSelector() 是 EnableAutoConfigurationImportSelector
// selectImports会获取到 spirng.factories中EnableAutoConfiguration下的类
String[] imports = deferredImport.getImportSelector().selectImports(configClass.getMetadata());
processImports(configClass, asSourceClass(configClass), asSourceClasses(imports), false);
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to process import candidates for configuration class [" +
configClass.getMetadata().getClassName() + "]", ex);
}
}
}
⭐️ processImports
private void processImports(ConfigurationClass configClass, SourceClass currentSourceClass,
Collection<SourceClass> importCandidates, boolean checkForCircularImports) throws IOException {
if (importCandidates.isEmpty()) {
return;
}
if (checkForCircularImports && isChainedImportOnStack(configClass)) {
this.problemReporter.error(new CircularImportProblem(configClass, this.importStack));
}
else {
this.importStack.push(configClass);
try {
// importCandidates 是被导入的类
// 1 SpringBoot中:
// importCandidates就是 spring.factories中EnableAutoConfiguration下的类
for (SourceClass candidate : importCandidates) {
// candidate是否是ImportSelector的类或其子类或子接口
if (candidate.isAssignable(ImportSelector.class)) {
// Candidate class is an ImportSelector -> delegate to it to determine imports
Class<?> candidateClass = candidate.loadClass();
ImportSelector selector = BeanUtils.instantiateClass(candidateClass, ImportSelector.class);
ParserStrategyUtils.invokeAwareMethods(
selector, this.environment, this.resourceLoader, this.registry);
if (this.deferredImportSelectors != null && selector instanceof DeferredImportSelector) {
this.deferredImportSelectors.add(
new DeferredImportSelectorHolder(configClass, (DeferredImportSelector) selector));
}
else {
String[] importClassNames = selector.selectImports(currentSourceClass.getMetadata());
Collection<SourceClass> importSourceClasses = asSourceClasses(importClassNames);
processImports(configClass, currentSourceClass, importSourceClasses, false);
}
}
else if (candidate.isAssignable(ImportBeanDefinitionRegistrar.class)) {
// Candidate class is an ImportBeanDefinitionRegistrar ->
// delegate to it to register additional bean definitions
Class<?> candidateClass = candidate.loadClass();
ImportBeanDefinitionRegistrar registrar =
BeanUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class);
ParserStrategyUtils.invokeAwareMethods(
registrar, this.environment, this.resourceLoader, this.registry);
configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata());
}
else {
// 处理@Configuration
// Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar ->
// process it as an @Configuration class
this.importStack.registerImport(
currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
processConfigurationClass(candidate.asConfigClass(configClass));
}
}
}
catch (BeanDefinitionStoreException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanDefinitionStoreException(
"Failed to process import candidates for configuration class [" +
configClass.getMetadata().getClassName() + "]", ex);
}
finally {
this.importStack.pop();
}
}
}
private boolean isChainedImportOnStack(ConfigurationClass configClass) {
if (this.importStack.contains(configClass)) {
String configClassName = configClass.getMetadata().getClassName();
AnnotationMetadata importingClass = this.importStack.getImportingClassFor(configClassName);
while (importingClass != null) {
if (configClassName.equals(importingClass.getClassName())) {
return true;
}
importingClass = this.importStack.getImportingClassFor(importingClass.getClassName());
}
}
return false;
}
ImportRegistry getImportRegistry() {
return this.importStack;
}
/**
* Factory method to obtain a {@link SourceClass} from a {@link ConfigurationClass}.
*/
private SourceClass asSourceClass(ConfigurationClass configurationClass) throws IOException {
AnnotationMetadata metadata = configurationClass.getMetadata();
if (metadata instanceof StandardAnnotationMetadata) {
return asSourceClass(((StandardAnnotationMetadata) metadata).getIntrospectedClass());
}
return asSourceClass(metadata.getClassName());
}
/**
* Factory method to obtain a {@link SourceClass} from a {@link Class}.
*/
SourceClass asSourceClass(Class<?> classType) throws IOException {
try {
// Sanity test that we can read annotations, if not fall back to ASM
classType.getAnnotations();
return new SourceClass(classType);
}
catch (Throwable ex) {
// Enforce ASM via class name resolution
return asSourceClass(classType.getName());
}
}
/**
* Factory method to obtain {@link SourceClass}s from class names.
*/
private Collection<SourceClass> asSourceClasses(String[] classNames) throws IOException {
List<SourceClass> annotatedClasses = new ArrayList<SourceClass>(classNames.length);
for (String className : classNames) {
annotatedClasses.add(asSourceClass(className));
}
return annotatedClasses;
}
/**
* Factory method to obtain a {@link SourceClass} from a class name.
*/
SourceClass asSourceClass(String className) throws IOException {
if (className.startsWith("java")) {
// Never use ASM for core java types
try {
return new SourceClass(this.resourceLoader.getClassLoader().loadClass(className));
}
catch (ClassNotFoundException ex) {
throw new NestedIOException("Failed to load class [" + className + "]", ex);
}
}
return new SourceClass(this.metadataReaderFactory.getMetadataReader(className));
}
@SuppressWarnings("serial")
private static class ImportStack extends ArrayDeque<ConfigurationClass> implements ImportRegistry {
private final MultiValueMap<String, AnnotationMetadata> imports = new LinkedMultiValueMap<String, AnnotationMetadata>();
public void registerImport(AnnotationMetadata importingClass, String importedClass) {
this.imports.add(importedClass, importingClass);
}
@Override
public AnnotationMetadata getImportingClassFor(String importedClass) {
List<AnnotationMetadata> list = this.imports.get(importedClass);
return (!CollectionUtils.isEmpty(list) ? list.get(list.size() - 1) : null);
}
@Override
public void removeImportingClass(String importingClass) {
for (List<AnnotationMetadata> list : this.imports.values()) {
for (Iterator<AnnotationMetadata> iterator = list.iterator(); iterator.hasNext();) {
if (iterator.next().getClassName().equals(importingClass)) {
iterator.remove();
break;
}
}
}
}
/**
* Given a stack containing (in order)
* <ul>
* <li>com.acme.Foo</li>
* <li>com.acme.Bar</li>
* <li>com.acme.Baz</li>
* </ul>
* return "[Foo->Bar->Baz]".
*/
@Override
public String toString() {
StringBuilder builder = new StringBuilder("[");
Iterator<ConfigurationClass> iterator = iterator();
while (iterator.hasNext()) {
builder.append(iterator.next().getSimpleName());
if (iterator.hasNext()) {
builder.append("->");
}
}
return builder.append(']').toString();
}
}
private static class DeferredImportSelectorHolder {
private final ConfigurationClass configurationClass;
private final DeferredImportSelector importSelector;
public DeferredImportSelectorHolder(ConfigurationClass configClass, DeferredImportSelector selector) {
this.configurationClass = configClass;
this.importSelector = selector;
}
public ConfigurationClass getConfigurationClass() {
return this.configurationClass;
}
public DeferredImportSelector getImportSelector() {
return this.importSelector;
}
}
/**
* Simple wrapper that allows annotated source classes to be dealt with
* in a uniform manner, regardless of how they are loaded.
*/
private class SourceClass {
private final Object source; // Class or MetadataReader
private final AnnotationMetadata metadata;
public SourceClass(Object source) {
this.source = source;
if (source instanceof Class) {
this.metadata = new StandardAnnotationMetadata((Class<?>) source, true);
}
else {
this.metadata = ((MetadataReader) source).getAnnotationMetadata();
}
}
public final AnnotationMetadata getMetadata() {
return this.metadata;
}
public Class<?> loadClass() throws ClassNotFoundException {
if (this.source instanceof Class) {
return (Class<?>) this.source;
}
String className = ((MetadataReader) this.source).getClassMetadata().getClassName();
return resourceLoader.getClassLoader().loadClass(className);
}
public boolean isAssignable(Class<?> clazz) throws IOException {
if (this.source instanceof Class) {
return clazz.isAssignableFrom((Class<?>) this.source);
}
return new AssignableTypeFilter(clazz).match((MetadataReader) this.source, metadataReaderFactory);
}
public ConfigurationClass asConfigClass(ConfigurationClass importedBy) throws IOException {
if (this.source instanceof Class) {
return new ConfigurationClass((Class<?>) this.source, importedBy);
}
return new ConfigurationClass((MetadataReader) this.source, importedBy);
}
public Collection<SourceClass> getMemberClasses() throws IOException {
Object sourceToProcess = this.source;
if (sourceToProcess instanceof Class) {
Class<?> sourceClass = (Class<?>) sourceToProcess;
try {
Class<?>[] declaredClasses = sourceClass.getDeclaredClasses();
List<SourceClass> members = new ArrayList<SourceClass>(declaredClasses.length);
for (Class<?> declaredClass : declaredClasses) {
members.add(asSourceClass(declaredClass));
}
return members;
}
catch (NoClassDefFoundError err) {
// getDeclaredClasses() failed because of non-resolvable dependencies
// -> fall back to ASM below
sourceToProcess = metadataReaderFactory.getMetadataReader(sourceClass.getName());
}
}
// ASM-based resolution - safe for non-resolvable classes as well
MetadataReader sourceReader = (MetadataReader) sourceToProcess;
String[] memberClassNames = sourceReader.getClassMetadata().getMemberClassNames();
List<SourceClass> members = new ArrayList<SourceClass>(memberClassNames.length);
for (String memberClassName : memberClassNames) {
try {
members.add(asSourceClass(memberClassName));
}
catch (IOException ex) {
// Let's skip it if it's not resolvable - we're just looking for candidates
if (logger.isDebugEnabled()) {
logger.debug("Failed to resolve member class [" + memberClassName +
"] - not considering it as a configuration class candidate");
}
}
}
return members;
}
public SourceClass getSuperClass() throws IOException {
if (this.source instanceof Class) {
return asSourceClass(((Class<?>) this.source).getSuperclass());
}
return asSourceClass(((MetadataReader) this.source).getClassMetadata().getSuperClassName());
}
public Set<SourceClass> getInterfaces() throws IOException {
Set<SourceClass> result = new LinkedHashSet<SourceClass>();
if (this.source instanceof Class) {
Class<?> sourceClass = (Class<?>) this.source;
for (Class<?> ifcClass : sourceClass.getInterfaces()) {
result.add(asSourceClass(ifcClass));
}
}
else {
for (String className : this.metadata.getInterfaceNames()) {
result.add(asSourceClass(className));
}
}
return result;
}
public Set<SourceClass> getAnnotations() throws IOException {
Set<SourceClass> result = new LinkedHashSet<SourceClass>();
for (String className : this.metadata.getAnnotationTypes()) {
try {
result.add(getRelated(className));
}
catch (Throwable ex) {
// An annotation not present on the classpath is being ignored
// by the JVM's class loading -> ignore here as well.
}
}
return result;
}
public Collection<SourceClass> getAnnotationAttributes(String annType, String attribute) throws IOException {
Map<String, Object> annotationAttributes = this.metadata.getAnnotationAttributes(annType, true);
if (annotationAttributes == null || !annotationAttributes.containsKey(attribute)) {
return Collections.emptySet();
}
String[] classNames = (String[]) annotationAttributes.get(attribute);
Set<SourceClass> result = new LinkedHashSet<SourceClass>();
for (String className : classNames) {
result.add(getRelated(className));
}
return result;
}
private SourceClass getRelated(String className) throws IOException {
if (this.source instanceof Class) {
try {
Class<?> clazz = ((Class<?>) this.source).getClassLoader().loadClass(className);
return asSourceClass(clazz);
}
catch (ClassNotFoundException ex) {
// Ignore -> fall back to ASM next, except for core java types.
if (className.startsWith("java")) {
throw new NestedIOException("Failed to load class [" + className + "]", ex);
}
return new SourceClass(metadataReaderFactory.getMetadataReader(className));
}
}
return asSourceClass(className);
}
@Override
public boolean equals(Object other) {
return (this == other || (other instanceof SourceClass &&
this.metadata.getClassName().equals(((SourceClass) other).metadata.getClassName())));
}
@Override
public int hashCode() {
return this.metadata.getClassName().hashCode();
}
@Override
public String toString() {
return this.metadata.getClassName();
}
}
/**
* {@link Problem} registered upon detection of a circular {@link Import}.
*/
private static class CircularImportProblem extends Problem {
public CircularImportProblem(ConfigurationClass attemptedImport, Deque<ConfigurationClass> importStack) {
super(String.format("A circular @Import has been detected: " +
"Illegal attempt by @Configuration class '%s' to import class '%s' as '%s' is " +
"already present in the current import stack %s", importStack.peek().getSimpleName(),
attemptedImport.getSimpleName(), attemptedImport.getSimpleName(), importStack),
new Location(importStack.peek().getResource(), attemptedImport.getMetadata()));
}
}
}