org.springframework.web.method.ControllerAdviceBean Maven / Gradle / Ivy
/*
* Copyright 2002-2012 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.ArrayList;
import java.util.List;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.annotation.Order;
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, an {@code ControllerAdviceBean} may be created from
* any object, including ones without an {@code @ControllerAdvice}.
*
* @author Rossen Stoyanchev
* @since 3.2
*/
public class ControllerAdviceBean implements Ordered {
private final Object bean;
private final int order;
private final BeanFactory beanFactory;
/**
* Create an instance 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) {
Assert.hasText(beanName, "'beanName' must not be null");
Assert.notNull(beanFactory, "'beanFactory' must not be null");
Assert.isTrue(beanFactory.containsBean(beanName),
"Bean factory [" + beanFactory + "] does not contain bean " + "with name [" + beanName + "]");
this.bean = beanName;
this.beanFactory = beanFactory;
this.order = initOrderFromBeanType(this.beanFactory.getType(beanName));
}
private static int initOrderFromBeanType(Class beanType) {
Order annot = AnnotationUtils.findAnnotation(beanType, Order.class);
return (annot != null) ? annot.value() : Ordered.LOWEST_PRECEDENCE;
}
/**
* Create an instance using the given bean instance.
* @param bean the bean
*/
public ControllerAdviceBean(Object bean) {
Assert.notNull(bean, "'bean' must not be null");
this.bean = bean;
this.order = initOrderFromBean(bean);
this.beanFactory = null;
}
private static int initOrderFromBean(Object bean) {
return (bean instanceof Ordered) ? ((Ordered) bean).getOrder() : initOrderFromBeanType(bean.getClass());
}
/**
* 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 : applicationContext.getBeanDefinitionNames()) {
if (applicationContext.findAnnotationOnBean(name, ControllerAdvice.class) != null) {
beans.add(new ControllerAdviceBean(name, applicationContext));
}
}
return beans;
}
/**
* Returns the order value extracted from the {@link ControllerAdvice}
* annotation or {@link Ordered#LOWEST_PRECEDENCE} otherwise.
*/
public int getOrder() {
return this.order;
}
/**
* Returns 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;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o != null && o instanceof ControllerAdviceBean) {
ControllerAdviceBean other = (ControllerAdviceBean) o;
return this.bean.equals(other.bean);
}
return false;
}
@Override
public int hashCode() {
return 31 * this.bean.hashCode();
}
@Override
public String toString() {
return bean.toString();
}
}