org.springframework.web.method.ControllerAdviceBean Maven / Gradle / Ivy
/*
* 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.web.method;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
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.AnnotationUtils;
import org.springframework.core.annotation.OrderUtils;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
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;
private final BeanFactory beanFactory;
private final int order;
private final Set basePackages;
private final List> assignableTypes;
private final List> annotations;
/**
* 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, BeanFactory beanFactory) {
this((Object) beanName, beanFactory);
}
private ControllerAdviceBean(Object bean, 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 =
AnnotatedElementUtils.findMergedAnnotation(beanType, ControllerAdvice.class);
if (annotation != null) {
this.basePackages = initBasePackages(annotation);
this.assignableTypes = Arrays.asList(annotation.assignableTypes());
this.annotations = Arrays.asList(annotation.annotations());
}
else {
this.basePackages = Collections.emptySet();
this.assignableTypes = Collections.emptyList();
this.annotations = Collections.emptyList();
}
}
/**
* 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.
*/
public Class getBeanType() {
Class clazz = (this.bean instanceof String ?
this.beanFactory.getType((String) this.bean) : this.bean.getClass());
return ClassUtils.getUserClass(clazz);
}
/**
* Return a bean instance if necessary resolving the bean name through the BeanFactory.
*/
public Object resolveBean() {
return (this.bean instanceof String ? this.beanFactory.getBean((String) this.bean) : this.bean);
}
/**
* Check whether the given bean type should be assisted by this
* {@code @ControllerAdvice} instance.
* @param beanType the type of the bean to check
* @see org.springframework.web.bind.annotation.ControllerAdvice
* @since 4.0
*/
public boolean isApplicableToBeanType(Class beanType) {
if (!hasSelectors()) {
return true;
}
else if (beanType != null) {
for (String basePackage : this.basePackages) {
if (beanType.getName().startsWith(basePackage)) {
return true;
}
}
for (Class clazz : this.assignableTypes) {
if (ClassUtils.isAssignable(clazz, beanType)) {
return true;
}
}
for (Class annotationClass : this.annotations) {
if (AnnotationUtils.findAnnotation(beanType, annotationClass) != null) {
return true;
}
}
}
return false;
}
private boolean hasSelectors() {
return (!this.basePackages.isEmpty() || !this.assignableTypes.isEmpty() || !this.annotations.isEmpty());
}
@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 applicationContext) {
List beans = new ArrayList();
for (String name : BeanFactoryUtils.beanNamesForTypeIncludingAncestors(applicationContext, Object.class)) {
if (applicationContext.findAnnotationOnBean(name, ControllerAdvice.class) != null) {
beans.add(new ControllerAdviceBean(name, applicationContext));
}
}
return beans;
}
private static int initOrderFromBean(Object bean) {
return (bean instanceof Ordered ? ((Ordered) bean).getOrder() : initOrderFromBeanType(bean.getClass()));
}
private static int initOrderFromBeanType(Class beanType) {
return OrderUtils.getOrder(beanType, Ordered.LOWEST_PRECEDENCE);
}
private static Set initBasePackages(ControllerAdvice annotation) {
Set basePackages = new LinkedHashSet();
for (String basePackage : annotation.basePackages()) {
if (StringUtils.hasText(basePackage)) {
basePackages.add(adaptBasePackage(basePackage));
}
}
for (Class markerClass : annotation.basePackageClasses()) {
basePackages.add(adaptBasePackage(ClassUtils.getPackageName(markerClass)));
}
return basePackages;
}
private static String adaptBasePackage(String basePackage) {
return (basePackage.endsWith(".") ? basePackage : basePackage + ".");
}
}