/*
* Copyright 2002-2016 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.lang.reflect.Method;
import java.util.function.Predicate;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.NoUniqueBeanDefinitionException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.AutowireCandidateQualifier;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.util.Assert;
/**
* Convenience methods performing bean lookups related to annotations, for example
* Spring's {@link Qualifier @Qualifier} annotation.
*
* @author Juergen Hoeller
* @author Chris Beams
* @since 3.1.2
* @see BeanFactoryUtils
*/
public abstract class BeanFactoryAnnotationUtils {
/**
* Obtain a bean of type {@code T} from the given {@code BeanFactory} declaring a
* qualifier (e.g. via {@code <qualifier>} or {@code @Qualifier}) matching the given
* qualifier, or having a bean name matching the given qualifier.
* @param beanFactory the BeanFactory to get the target bean from
* @param beanType the type of bean to retrieve
* @param qualifier the qualifier for selecting between multiple bean matches
* @return the matching bean of type {@code T} (never {@code null})
* @throws NoUniqueBeanDefinitionException if multiple matching beans of type {@code T} found
* @throws NoSuchBeanDefinitionException if no matching bean of type {@code T} found
* @throws BeansException if the bean could not be created
* @see BeanFactory#getBean(Class)
*/
public static <T> T qualifiedBeanOfType(BeanFactory beanFactory, Class<T> beanType, String qualifier)
throws BeansException {
Assert.notNull(beanFactory, "BeanFactory must not be null");
if (beanFactory instanceof ConfigurableListableBeanFactory) {
// Full qualifier matching supported.
return qualifiedBeanOfType((ConfigurableListableBeanFactory) beanFactory, beanType, qualifier);
}
else if (beanFactory.containsBean(qualifier)) {
// Fallback: target bean at least found by bean name.
return beanFactory.getBean(qualifier, beanType);
}
else {
throw new NoSuchBeanDefinitionException(qualifier, "No matching " + beanType.getSimpleName() +
" bean found for bean name '" + qualifier +
"'! (Note: Qualifier matching not supported because given " +
"BeanFactory does not implement ConfigurableListableBeanFactory.)");
}
}
/**
* Obtain a bean of type {@code T} from the given {@code BeanFactory} declaring a qualifier
* (e.g. {@code <qualifier>} or {@code @Qualifier}) matching the given qualifier).
* @param bf the BeanFactory to get the target bean from
* @param beanType the type of bean to retrieve
* @param qualifier the qualifier for selecting between multiple bean matches
* @return the matching bean of type {@code T} (never {@code null})
*/
private static <T> T qualifiedBeanOfType(ConfigurableListableBeanFactory bf, Class<T> beanType, String qualifier) {
String[] candidateBeans = BeanFactoryUtils.beanNamesForTypeIncludingAncestors(bf, beanType);
String matchingBean = null;
for (String beanName : candidateBeans) {
if (isQualifierMatch(qualifier::equals, beanName, bf)) {
if (matchingBean != null) {
throw new NoUniqueBeanDefinitionException(beanType, matchingBean, beanName);
}
matchingBean = beanName;
}
}
if (matchingBean != null) {
return bf.getBean(matchingBean, beanType);
}
else if (bf.containsBean(qualifier)) {
// Fallback: target bean at least found by bean name - probably a manually registered singleton.
return bf.getBean(qualifier, beanType);
}
else {
throw new NoSuchBeanDefinitionException(qualifier, "No matching " + beanType.getSimpleName() +
" bean found for qualifier '" + qualifier + "' - neither qualifier match nor bean name match!");
}
}
/**
* Check whether the named bean declares a qualifier of the given name.
* @param qualifier the qualifier to match
* @param beanName the name of the candidate bean
* @param beanFactory the {@code BeanFactory} from which to retrieve the named bean
* @return {@code true} if either the bean definition (in the XML case)
* or the bean's factory method (in the {@code @Bean} case) defines a matching
* qualifier value (through {@code <qualifier>} or {@code @Qualifier})
* @since 5.0
*/
public static boolean isQualifierMatch(Predicate<String> qualifier, String beanName, BeanFactory beanFactory) {
// Try quick bean name or alias match first...
if (qualifier.test(beanName)) {
return true;
}
if (beanFactory != null) {
for (String alias : beanFactory.getAliases(beanName)) {
if (qualifier.test(alias)) {
return true;
}
}
try {
if (beanFactory instanceof ConfigurableBeanFactory) {
BeanDefinition bd = ((ConfigurableBeanFactory) beanFactory).getMergedBeanDefinition(beanName);
// Explicit qualifier metadata on bean definition? (typically in XML definition)
if (bd instanceof AbstractBeanDefinition) {
AbstractBeanDefinition abd = (AbstractBeanDefinition) bd;
AutowireCandidateQualifier candidate = abd.getQualifier(Qualifier.class.getName());
if (candidate != null) {
Object value = candidate.getAttribute(AutowireCandidateQualifier.VALUE_KEY);
if (value != null && qualifier.test(value.toString())) {
return true;
}
}
}
// Corresponding qualifier on factory method? (typically in configuration class)
if (bd instanceof RootBeanDefinition) {
Method factoryMethod = ((RootBeanDefinition) bd).getResolvedFactoryMethod();
if (factoryMethod != null) {
Qualifier targetAnnotation = AnnotationUtils.getAnnotation(factoryMethod, Qualifier.class);
if (targetAnnotation != null) {
return qualifier.test(targetAnnotation.value());
}
}
}
}
// Corresponding qualifier on bean implementation class? (for custom user types)
Class<?> beanType = beanFactory.getType(beanName);
if (beanType != null) {
Qualifier targetAnnotation = AnnotationUtils.getAnnotation(beanType, Qualifier.class);
if (targetAnnotation != null) {
return qualifier.test(targetAnnotation.value());
}
}
}
catch (NoSuchBeanDefinitionException ex) {
// Ignore - can't compare qualifiers for a manually registered singleton object
}
}
return false;
}
}