org.springframework.web.method.ControllerAdviceBean Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.web.method;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.core.annotation.OrderUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.web.bind.annotation.ControllerAdvice;
/**
* Encapsulates information about an {@linkplain ControllerAdvice @ControllerAdvice}
* Spring-managed bean without necessarily requiring it to be instantiated.
*
* The {@link #findAnnotatedBeans(ApplicationContext)} method can be used to
* discover such beans. However, a {@code ControllerAdviceBean} may be created
* from any object, including ones without an {@code @ControllerAdvice}.
*
* @author Rossen Stoyanchev
* @author Brian Clozel
* @author Juergen Hoeller
* @since 3.2
*/
public class ControllerAdviceBean implements Ordered {
private final Object bean;
@Nullable
private final BeanFactory beanFactory;
private final int order;
private final HandlerTypePredicate beanTypePredicate;
/**
* Create a {@code ControllerAdviceBean} using the given bean instance.
* @param bean the bean instance
*/
public ControllerAdviceBean(Object bean) {
this(bean, null);
}
/**
* Create a {@code ControllerAdviceBean} using the given bean name.
* @param beanName the name of the bean
* @param beanFactory a BeanFactory that can be used later to resolve the bean
*/
public ControllerAdviceBean(String beanName, @Nullable BeanFactory beanFactory) {
this((Object) beanName, beanFactory);
}
private ControllerAdviceBean(Object bean, @Nullable BeanFactory beanFactory) {
this.bean = bean;
this.beanFactory = beanFactory;
Class beanType;
if (bean instanceof String) {
String beanName = (String) bean;
Assert.hasText(beanName, "Bean name must not be null");
Assert.notNull(beanFactory, "BeanFactory must not be null");
if (!beanFactory.containsBean(beanName)) {
throw new IllegalArgumentException("BeanFactory [" + beanFactory +
"] does not contain specified controller advice bean '" + beanName + "'");
}
beanType = this.beanFactory.getType(beanName);
this.order = initOrderFromBeanType(beanType);
}
else {
Assert.notNull(bean, "Bean must not be null");
beanType = bean.getClass();
this.order = initOrderFromBean(bean);
}
ControllerAdvice annotation = (beanType != null ?
AnnotatedElementUtils.findMergedAnnotation(beanType, ControllerAdvice.class) : null);
if (annotation != null) {
this.beanTypePredicate = HandlerTypePredicate.builder()
.basePackage(annotation.basePackages())
.basePackageClass(annotation.basePackageClasses())
.assignableType(annotation.assignableTypes())
.annotation(annotation.annotations())
.build();
}
else {
this.beanTypePredicate = HandlerTypePredicate.forAnyHandlerType();
}
}
/**
* Returns the order value extracted from the {@link ControllerAdvice}
* annotation, or {@link Ordered#LOWEST_PRECEDENCE} otherwise.
*/
@Override
public int getOrder() {
return this.order;
}
/**
* Return the type of the contained bean.
*
If the bean type is a CGLIB-generated class, the original
* user-defined class is returned.
*/
@Nullable
public Class getBeanType() {
Class beanType = (this.bean instanceof String ?
obtainBeanFactory().getType((String) this.bean) : this.bean.getClass());
return (beanType != null ? ClassUtils.getUserClass(beanType) : null);
}
/**
* Return a bean instance if necessary resolving the bean name through the BeanFactory.
*/
public Object resolveBean() {
return (this.bean instanceof String ? obtainBeanFactory().getBean((String) this.bean) : this.bean);
}
private BeanFactory obtainBeanFactory() {
Assert.state(this.beanFactory != null, "No BeanFactory set");
return this.beanFactory;
}
/**
* Check whether the given bean type should be assisted by this
* {@code @ControllerAdvice} instance.
* @param beanType the type of the bean to check
* @since 4.0
* @see org.springframework.web.bind.annotation.ControllerAdvice
*/
public boolean isApplicableToBeanType(@Nullable Class beanType) {
return this.beanTypePredicate.test(beanType);
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof ControllerAdviceBean)) {
return false;
}
ControllerAdviceBean otherAdvice = (ControllerAdviceBean) other;
return (this.bean.equals(otherAdvice.bean) && this.beanFactory == otherAdvice.beanFactory);
}
@Override
public int hashCode() {
return this.bean.hashCode();
}
@Override
public String toString() {
return this.bean.toString();
}
/**
* Find the names of beans annotated with
* {@linkplain ControllerAdvice @ControllerAdvice} in the given
* ApplicationContext and wrap them as {@code ControllerAdviceBean} instances.
*/
public static List findAnnotatedBeans(ApplicationContext context) {
return Arrays.stream(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(context, Object.class))
.filter(name -> context.findAnnotationOnBean(name, ControllerAdvice.class) != null)
.map(name -> new ControllerAdviceBean(name, context))
.collect(Collectors.toList());
}
private static int initOrderFromBean(Object bean) {
return (bean instanceof Ordered ? ((Ordered) bean).getOrder() : initOrderFromBeanType(bean.getClass()));
}
private static int initOrderFromBeanType(@Nullable Class beanType) {
Integer order = null;
if (beanType != null) {
order = OrderUtils.getOrder(beanType);
}
return (order != null ? order : Ordered.LOWEST_PRECEDENCE);
}
}