org.springframework.beans.factory.config.BeanReferenceFactoryBean Maven / Gradle / Ivy
/*
* Copyright 2002-2007 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.config;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.FactoryBeanNotInitializedException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.SmartFactoryBean;
/**
* FactoryBean that exposes an arbitrary target bean under a different name.
*
* Usually, the target bean will reside in a different bean definition file,
* using this FactoryBean to link it in and expose it under a different name.
* Effectively, this corresponds to an alias for the target bean.
*
*
NOTE: For XML bean definition files, an <alias>
* tag is available that effectively achieves the same.
*
*
A special capability of this FactoryBean is enabled through its configuration
* as bean definition: The "targetBeanName" can be substituted through a placeholder,
* in combination with Spring's {@link PropertyPlaceholderConfigurer}.
* Thanks to Marcus Bristav for pointing this out!
*
* @author Juergen Hoeller
* @since 1.2
* @see #setTargetBeanName
* @see PropertyPlaceholderConfigurer
*/
public class BeanReferenceFactoryBean implements SmartFactoryBean, BeanFactoryAware {
private String targetBeanName;
private BeanFactory beanFactory;
/**
* Set the name of the target bean.
*
This property is required. The value for this property can be
* substituted through a placeholder, in combination with Spring's
* PropertyPlaceholderConfigurer.
* @param targetBeanName the name of the target bean
* @see PropertyPlaceholderConfigurer
*/
public void setTargetBeanName(String targetBeanName) {
this.targetBeanName = targetBeanName;
}
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
if (this.targetBeanName == null) {
throw new IllegalArgumentException("'targetBeanName' is required");
}
if (!this.beanFactory.containsBean(this.targetBeanName)) {
throw new NoSuchBeanDefinitionException(this.targetBeanName, this.beanFactory.toString());
}
}
public Object getObject() throws BeansException {
if (this.beanFactory == null) {
throw new FactoryBeanNotInitializedException();
}
return this.beanFactory.getBean(this.targetBeanName);
}
public Class getObjectType() {
if (this.beanFactory == null) {
return null;
}
return this.beanFactory.getType(this.targetBeanName);
}
public boolean isSingleton() {
if (this.beanFactory == null) {
throw new FactoryBeanNotInitializedException();
}
return this.beanFactory.isSingleton(this.targetBeanName);
}
public boolean isPrototype() {
if (this.beanFactory == null) {
throw new FactoryBeanNotInitializedException();
}
return this.beanFactory.isPrototype(this.targetBeanName);
}
}