org.springframework.context.annotation.ContextAnnotationAutowireCandidateResolver Maven / Gradle / Ivy
/*
* 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.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver;
import org.springframework.beans.factory.config.DependencyDescriptor;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.core.MethodParameter;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.util.Assert;
/**
* Complete implementation of the
* {@link org.springframework.beans.factory.support.AutowireCandidateResolver} strategy
* interface, providing support for qualifier annotations as well as for lazy resolution
* driven by the {@link Lazy} annotation in the {@code context.annotation} package.
*
* @author Juergen Hoeller
* @since 4.0
*/
public class ContextAnnotationAutowireCandidateResolver extends QualifierAnnotationAutowireCandidateResolver {
@Override
public Object getLazyResolutionProxyIfNecessary(DependencyDescriptor descriptor, String beanName) {
return (isLazy(descriptor) ? buildLazyResolutionProxy(descriptor, beanName) : null);
}
protected boolean isLazy(DependencyDescriptor descriptor) {
for (Annotation ann : descriptor.getAnnotations()) {
Lazy lazy = AnnotationUtils.getAnnotation(ann, Lazy.class);
if (lazy != null && lazy.value()) {
return true;
}
}
MethodParameter methodParam = descriptor.getMethodParameter();
if (methodParam != null) {
Method method = methodParam.getMethod();
if (method == null || void.class == method.getReturnType()) {
Lazy lazy = AnnotationUtils.getAnnotation(methodParam.getAnnotatedElement(), Lazy.class);
if (lazy != null && lazy.value()) {
return true;
}
}
}
return false;
}
protected Object buildLazyResolutionProxy(final DependencyDescriptor descriptor, final String beanName) {
Assert.state(getBeanFactory() instanceof DefaultListableBeanFactory,
"BeanFactory needs to be a DefaultListableBeanFactory");
final DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) getBeanFactory();
TargetSource ts = new TargetSource() {
@Override
public Class getTargetClass() {
return descriptor.getDependencyType();
}
@Override
public boolean isStatic() {
return false;
}
@Override
public Object getTarget() {
Object target = beanFactory.doResolveDependency(descriptor, beanName, null, null);
if (target == null) {
Class type = getTargetClass();
if (Map.class == type) {
return Collections.EMPTY_MAP;
}
else if (List.class == type) {
return Collections.EMPTY_LIST;
}
else if (Set.class == type || Collection.class == type) {
return Collections.EMPTY_SET;
}
throw new NoSuchBeanDefinitionException(descriptor.getResolvableType(),
"Optional dependency not present for lazy injection point");
}
return target;
}
@Override
public void releaseTarget(Object target) {
}
};
ProxyFactory pf = new ProxyFactory();
pf.setTargetSource(ts);
Class dependencyType = descriptor.getDependencyType();
if (dependencyType.isInterface()) {
pf.addInterface(dependencyType);
}
return pf.getProxy(beanFactory.getBeanClassLoader());
}
}