/*
* 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.beans.factory.annotation;
import java.beans.PropertyDescriptor;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.factory.BeanCreationException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.DependencyDescriptor;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.support.MergedBeanDefinitionPostProcessor;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.core.GenericTypeResolver;
import org.springframework.core.MethodParameter;
import org.springframework.core.Ordered;
import org.springframework.core.PriorityOrdered;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;
/**
* {@link org.springframework.beans.factory.config.BeanPostProcessor} implementation
* that autowires annotated fields, setter methods and arbitrary config methods.
* Such members to be injected are detected through a Java 5 annotation:
* by default, Spring's {@link Autowired} annotation.
*
* <p>Only one constructor (at max) of any given bean class may carry this
* annotation with the 'required' parameter set to <code>true</code>,
* indicating <i>the</i> constructor to autowire when used as a Spring bean.
* If multiple <i>non-required</i> constructors carry the annotation, they
* will be considered as candidates for autowiring. The constructor with
* the greatest number of dependencies that can be satisfied by matching
* beans in the Spring container will be chosen. If none of the candidates
* can be satisfied, then a default constructor (if present) will be used.
* An annotated constructor does not have to be public.
*
* <p>Fields are injected right after construction of a bean, before any
* config methods are invoked. Such a config field does not have to be public.
*
* <p>Config methods may have an arbitrary name and any number of arguments;
* each of those arguments will be autowired with a matching bean in the
* Spring container. Bean property setter methods are effectively just
* a special case of such a general config method. Such config methods
* do not have to be public.
*
* <p>Also supports JSR-330's {@link javax.inject.Inject} annotation, if available.
*
* <p>Note: A default AutowiredAnnotationBeanPostProcessor will be registered
* by the "context:annotation-config" and "context:component-scan" XML tags.
* Remove or turn off the default annotation configuration there if you intend
* to specify a custom AutowiredAnnotationBeanPostProcessor bean definition.
* <p><b>NOTE:</b> Annotation injection will be performed <i>before</i> XML injection; thus
* the latter configuration will override the former for properties wired through
* both approaches.
*
* @author Juergen Hoeller
* @author Mark Fisher
* @since 2.5
* @see #setAutowiredAnnotationType
* @see Autowired
*/
public class AutowiredAnnotationBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter
implements MergedBeanDefinitionPostProcessor, PriorityOrdered, BeanFactoryAware {
protected final Log logger = LogFactory.getLog(getClass());
private final Set<Class<? extends Annotation>> autowiredAnnotationTypes =
new LinkedHashSet<Class<? extends Annotation>>();
private String requiredParameterName = "required";
private boolean requiredParameterValue = true;
private int order = Ordered.LOWEST_PRECEDENCE - 2;
private ConfigurableListableBeanFactory beanFactory;
private final Map<Class<?>, Constructor[]> candidateConstructorsCache =
new ConcurrentHashMap<Class<?>, Constructor[]>();
private final Map<Class<?>, InjectionMetadata> injectionMetadataCache =
new ConcurrentHashMap<Class<?>, InjectionMetadata>();
/**
* Create a new AutowiredAnnotationBeanPostProcessor
* for Spring's standard {@link Autowired} annotation.
* <p>Also supports JSR-330's {@link javax.inject.Inject} annotation, if available.
*/
@SuppressWarnings("unchecked")
public AutowiredAnnotationBeanPostProcessor() {
this.autowiredAnnotationTypes.add(Autowired.class);
this.autowiredAnnotationTypes.add(Value.class);
ClassLoader cl = AutowiredAnnotationBeanPostProcessor.class.getClassLoader();
try {
this.autowiredAnnotationTypes.add((Class<? extends Annotation>) cl.loadClass("javax.inject.Inject"));
logger.info("JSR-330 'javax.inject.Inject' annotation found and supported for autowiring");
}
catch (ClassNotFoundException ex) {
// JSR-330 API not available - simply skip.
}
}
/**
* Set the 'autowired' annotation type, to be used on constructors, fields,
* setter methods and arbitrary config methods.
* <p>The default autowired annotation type is the Spring-provided
* {@link Autowired} annotation, as well as {@link Value}.
* <p>This setter property exists so that developers can provide their own
* (non-Spring-specific) annotation type to indicate that a member is
* supposed to be autowired.
*/
public void setAutowiredAnnotationType(Class<? extends Annotation> autowiredAnnotationType) {
Assert.notNull(autowiredAnnotationType, "'autowiredAnnotationType' must not be null");
this.autowiredAnnotationTypes.clear();
this.autowiredAnnotationTypes.add(autowiredAnnotationType);
}
/**
* Set the 'autowired' annotation types, to be used on constructors, fields,
* setter methods and arbitrary config methods.
* <p>The default autowired annotation type is the Spring-provided
* {@link Autowired} annotation, as well as {@link Value}.
* <p>This setter property exists so that developers can provide their own
* (non-Spring-specific) annotation types to indicate that a member is
* supposed to be autowired.
*/
public void setAutowiredAnnotationTypes(Set<Class<? extends Annotation>> autowiredAnnotationTypes) {
Assert.notEmpty(autowiredAnnotationTypes, "'autowiredAnnotationTypes' must not be empty");
this.autowiredAnnotationTypes.clear();
this.autowiredAnnotationTypes.addAll(autowiredAnnotationTypes);
}
/**
* Set the name of a parameter of the annotation that specifies
* whether it is required.
* @see #setRequiredParameterValue(boolean)
*/
public void setRequiredParameterName(String requiredParameterName) {
this.requiredParameterName = requiredParameterName;
}
/**
* Set the boolean value that marks a dependency as required
* <p>For example if using 'required=true' (the default),
* this value should be <code>true</code>; but if using
* 'optional=false', this value should be <code>false</code>.
* @see #setRequiredParameterName(String)
*/
public void setRequiredParameterValue(boolean requiredParameterValue) {
this.requiredParameterValue = requiredParameterValue;
}
public void setOrder(int order) {
this.order = order;
}
public int getOrder() {
return this.order;
}
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
if (!(beanFactory instanceof ConfigurableListableBeanFactory)) {
throw new IllegalArgumentException(
"AutowiredAnnotationBeanPostProcessor requires a ConfigurableListableBeanFactory");
}
this.beanFactory = (ConfigurableListableBeanFactory) beanFactory;
}
public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class beanType, String beanName) {
if (beanType != null) {
InjectionMetadata metadata = findAutowiringMetadata(beanType);
metadata.checkConfigMembers(beanDefinition);
}
}
@Override
public Constructor[] determineCandidateConstructors(Class beanClass, String beanName) throws BeansException {
// Quick check on the concurrent map first, with minimal locking.
Constructor[] candidateConstructors = this.candidateConstructorsCache.get(beanClass);
if (candidateConstructors == null) {
synchronized (this.candidateConstructorsCache) {
candidateConstructors = this.candidateConstructorsCache.get(beanClass);
if (candidateConstructors == null) {
Constructor[] rawCandidates = beanClass.getDeclaredConstructors();
List<Constructor> candidates = new ArrayList<Constructor>(rawCandidates.length);
Constructor requiredConstructor = null;
Constructor defaultConstructor = null;
for (Constructor<?> candidate : rawCandidates) {
Annotation annotation = findAutowiredAnnotation(candidate);
if (annotation != null) {
if (requiredConstructor != null) {
throw new BeanCreationException("Invalid autowire-marked constructor: " + candidate +
". Found another constructor with 'required' Autowired annotation: " +
requiredConstructor);
}
if (candidate.getParameterTypes().length == 0) {
throw new IllegalStateException(
"Autowired annotation requires at least one argument: " + candidate);
}
boolean required = determineRequiredStatus(annotation);
if (required) {
if (!candidates.isEmpty()) {
throw new BeanCreationException(
"Invalid autowire-marked constructors: " + candidates +
". Found another constructor with 'required' Autowired annotation: " +
requiredConstructor);
}
requiredConstructor = candidate;
}
candidates.add(candidate);
}
else if (candidate.getParameterTypes().length == 0) {
defaultConstructor = candidate;
}
}
if (!candidates.isEmpty()) {
// Add default constructor to list of optional constructors, as fallback.
if (requiredConstructor == null && defaultConstructor != null) {
candidates.add(defaultConstructor);
}
candidateConstructors = candidates.toArray(new Constructor[candidates.size()]);
}
else {
candidateConstructors = new Constructor[0];
}
this.candidateConstructorsCache.put(beanClass, candidateConstructors);
}
}
}
return (candidateConstructors.length > 0 ? candidateConstructors : null);
}
@Override
public PropertyValues postProcessPropertyValues(
PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException {
InjectionMetadata metadata = findAutowiringMetadata(bean.getClass());
try {
metadata.inject(bean, beanName, pvs);
}
catch (Throwable ex) {
throw new BeanCreationException(beanName, "Injection of autowired dependencies failed", ex);
}
return pvs;
}
/**
* 'Native' processing method for direct calls with an arbitrary target instance,
* resolving all of its fields and methods which are annotated with <code>@Autowired</code>.
* @param bean the target instance to process
* @throws BeansException if autowiring failed
*/
public void processInjection(Object bean) throws BeansException {
Class<?> clazz = bean.getClass();
InjectionMetadata metadata = findAutowiringMetadata(clazz);
try {
metadata.inject(bean, null, null);
}
catch (Throwable ex) {
throw new BeanCreationException("Injection of autowired dependencies failed for class [" + clazz + "]", ex);
}
}
private InjectionMetadata findAutowiringMetadata(Class clazz) {
// Quick check on the concurrent map first, with minimal locking.
InjectionMetadata metadata = this.injectionMetadataCache.get(clazz);
if (metadata == null) {
synchronized (this.injectionMetadataCache) {
metadata = this.injectionMetadataCache.get(clazz);
if (metadata == null) {
metadata = buildAutowiringMetadata(clazz);
this.injectionMetadataCache.put(clazz, metadata);
}
}
}
return metadata;
}
private InjectionMetadata buildAutowiringMetadata(Class clazz) {
LinkedList<InjectionMetadata.InjectedElement> elements = new LinkedList<InjectionMetadata.InjectedElement>();
Class<?> targetClass = clazz;
do {
LinkedList<InjectionMetadata.InjectedElement> currElements = new LinkedList<InjectionMetadata.InjectedElement>();
for (Field field : targetClass.getDeclaredFields()) {
Annotation annotation = findAutowiredAnnotation(field);
if (annotation != null) {
if (Modifier.isStatic(field.getModifiers())) {
if (logger.isWarnEnabled()) {
logger.warn("Autowired annotation is not supported on static fields: " + field);
}
continue;
}
boolean required = determineRequiredStatus(annotation);
currElements.add(new AutowiredFieldElement(field, required));
}
}
for (Method method : targetClass.getDeclaredMethods()) {
Annotation annotation = findAutowiredAnnotation(method);
if (annotation != null && method.equals(ClassUtils.getMostSpecificMethod(method, clazz))) {
if (Modifier.isStatic(method.getModifiers())) {
if (logger.isWarnEnabled()) {
logger.warn("Autowired annotation is not supported on static methods: " + method);
}
continue;
}
if (method.getParameterTypes().length == 0) {
if (logger.isWarnEnabled()) {
logger.warn("Autowired annotation should be used on methods with actual parameters: " + method);
}
}
boolean required = determineRequiredStatus(annotation);
PropertyDescriptor pd = BeanUtils.findPropertyForMethod(method);
currElements.add(new AutowiredMethodElement(method, required, pd));
}
}
elements.addAll(0, currElements);
targetClass = targetClass.getSuperclass();
}
while (targetClass != null && targetClass != Object.class);
return new InjectionMetadata(clazz, elements);
}
private Annotation findAutowiredAnnotation(AccessibleObject ao) {
for (Class<? extends Annotation> type : this.autowiredAnnotationTypes) {
Annotation annotation = ao.getAnnotation(type);
if (annotation != null) {
return annotation;
}
}
return null;
}
/**
* Obtain all beans of the given type as autowire candidates.
* @param type the type of the bean
* @return the target beans, or an empty Collection if no bean of this type is found
* @throws BeansException if bean retrieval failed
*/
protected <T> Map<String, T> findAutowireCandidates(Class<T> type) throws BeansException {
if (this.beanFactory == null) {
throw new IllegalStateException("No BeanFactory configured - " +
"override the getBeanOfType method or specify the 'beanFactory' property");
}
return BeanFactoryUtils.beansOfTypeIncludingAncestors(this.beanFactory, type);
}
/**
* Determine if the annotated field or method requires its dependency.
* <p>A 'required' dependency means that autowiring should fail when no beans
* are found. Otherwise, the autowiring process will simply bypass the field
* or method when no beans are found.
* @param annotation the Autowired annotation
* @return whether the annotation indicates that a dependency is required
*/
protected boolean determineRequiredStatus(Annotation annotation) {
try {
Method method = ReflectionUtils.findMethod(annotation.annotationType(), this.requiredParameterName);
return (this.requiredParameterValue == (Boolean) ReflectionUtils.invokeMethod(method, annotation));
}
catch (Exception ex) {
// required by default
return true;
}
}
/**
* Register the specified bean as dependent on the autowired beans.
*/
private void registerDependentBeans(String beanName, Set<String> autowiredBeanNames) {
if (beanName != null) {
for (String autowiredBeanName : autowiredBeanNames) {
beanFactory.registerDependentBean(autowiredBeanName, beanName);
if (logger.isDebugEnabled()) {
logger.debug(
"Autowiring by type from bean name '" + beanName + "' to bean named '" + autowiredBeanName +
"'");
}
}
}
}
/**
* Resolve the specified cached method argument or field value.
*/
private Object resolvedCachedArgument(String beanName, Object cachedArgument) {
if (cachedArgument instanceof DependencyDescriptor) {
DependencyDescriptor descriptor = (DependencyDescriptor) cachedArgument;
TypeConverter typeConverter = beanFactory.getTypeConverter();
return beanFactory.resolveDependency(descriptor, beanName, null, typeConverter);
}
else if (cachedArgument instanceof RuntimeBeanReference) {
return beanFactory.getBean(((RuntimeBeanReference) cachedArgument).getBeanName());
}
else {
return cachedArgument;
}
}
/**
* Class representing injection information about an annotated field.
*/
private class AutowiredFieldElement extends InjectionMetadata.InjectedElement {
private final boolean required;
private volatile boolean cached = false;
private volatile Object cachedFieldValue;
public AutowiredFieldElement(Field field, boolean required) {
super(field, null);
this.required = required;
}
@Override
protected void inject(Object bean, String beanName, PropertyValues pvs) throws Throwable {
Field field = (Field) this.member;
try {
Object value;
if (this.cached) {
value = resolvedCachedArgument(beanName, this.cachedFieldValue);
}
else {
DependencyDescriptor descriptor = new DependencyDescriptor(field, this.required);
Set<String> autowiredBeanNames = new LinkedHashSet<String>(1);
TypeConverter typeConverter = beanFactory.getTypeConverter();
value = beanFactory.resolveDependency(descriptor, beanName, autowiredBeanNames, typeConverter);
synchronized (this) {
if (!this.cached) {
if (value != null || this.required) {
this.cachedFieldValue = descriptor;
registerDependentBeans(beanName, autowiredBeanNames);
if (autowiredBeanNames.size() == 1) {
String autowiredBeanName = autowiredBeanNames.iterator().next();
if (beanFactory.containsBean(autowiredBeanName)) {
if (beanFactory.isTypeMatch(autowiredBeanName, field.getType())) {
this.cachedFieldValue = new RuntimeBeanReference(autowiredBeanName);
}
}
}
}
else {
this.cachedFieldValue = null;
}
this.cached = true;
}
}
}
if (value != null) {
ReflectionUtils.makeAccessible(field);
field.set(bean, value);
}
}
catch (Throwable ex) {
throw new BeanCreationException("Could not autowire field: " + field, ex);
}
}
}
/**
* Class representing injection information about an annotated method.
*/
private class AutowiredMethodElement extends InjectionMetadata.InjectedElement {
private final boolean required;
private volatile boolean cached = false;
private volatile Object[] cachedMethodArguments;
public AutowiredMethodElement(Method method, boolean required, PropertyDescriptor pd) {
super(method, pd);
this.required = required;
}
@Override
protected void inject(Object bean, String beanName, PropertyValues pvs) throws Throwable {
if (checkPropertySkipping(pvs)) {
return;
}
Method method = (Method) this.member;
try {
Object[] arguments;
if (this.cached) {
// Shortcut for avoiding synchronization...
arguments = resolveCachedArguments(beanName);
}
else {
Class[] paramTypes = method.getParameterTypes();
arguments = new Object[paramTypes.length];
DependencyDescriptor[] descriptors = new DependencyDescriptor[paramTypes.length];
Set<String> autowiredBeanNames = new LinkedHashSet<String>(paramTypes.length);
TypeConverter typeConverter = beanFactory.getTypeConverter();
for (int i = 0; i < arguments.length; i++) {
MethodParameter methodParam = new MethodParameter(method, i);
GenericTypeResolver.resolveParameterType(methodParam, bean.getClass());
descriptors[i] = new DependencyDescriptor(methodParam, this.required);
arguments[i] = beanFactory.resolveDependency(
descriptors[i], beanName, autowiredBeanNames, typeConverter);
if (arguments[i] == null && !this.required) {
arguments = null;
break;
}
}
synchronized (this) {
if (!this.cached) {
if (arguments != null) {
this.cachedMethodArguments = new Object[arguments.length];
for (int i = 0; i < arguments.length; i++) {
this.cachedMethodArguments[i] = descriptors[i];
}
registerDependentBeans(beanName, autowiredBeanNames);
if (autowiredBeanNames.size() == paramTypes.length) {
Iterator<String> it = autowiredBeanNames.iterator();
for (int i = 0; i < paramTypes.length; i++) {
String autowiredBeanName = it.next();
if (beanFactory.containsBean(autowiredBeanName)) {
if (beanFactory.isTypeMatch(autowiredBeanName, paramTypes[i])) {
this.cachedMethodArguments[i] = new RuntimeBeanReference(autowiredBeanName);
}
}
}
}
}
else {
this.cachedMethodArguments = null;
}
this.cached = true;
}
}
}
if (arguments != null) {
ReflectionUtils.makeAccessible(method);
method.invoke(bean, arguments);
}
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
catch (Throwable ex) {
throw new BeanCreationException("Could not autowire method: " + method, ex);
}
}
private Object[] resolveCachedArguments(String beanName) {
if (this.cachedMethodArguments == null) {
return null;
}
Object[] arguments = new Object[this.cachedMethodArguments.length];
for (int i = 0; i < arguments.length; i++) {
arguments[i] = resolvedCachedArgument(beanName, this.cachedMethodArguments[i]);
}
return arguments;
}
}
}
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