001/*
002 * Copyright 2002-2015 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.beans.factory.config;
018
019import org.springframework.beans.BeansException;
020
021/**
022 * Factory hook that allows for custom modification of new bean instances,
023 * e.g. checking for marker interfaces or wrapping them with proxies.
024 *
025 * <p>ApplicationContexts can autodetect BeanPostProcessor beans in their
026 * bean definitions and apply them to any beans subsequently created.
027 * Plain bean factories allow for programmatic registration of post-processors,
028 * applying to all beans created through this factory.
029 *
030 * <p>Typically, post-processors that populate beans via marker interfaces
031 * or the like will implement {@link #postProcessBeforeInitialization},
032 * while post-processors that wrap beans with proxies will normally
033 * implement {@link #postProcessAfterInitialization}.
034 *
035 * @author Juergen Hoeller
036 * @since 10.10.2003
037 * @see InstantiationAwareBeanPostProcessor
038 * @see DestructionAwareBeanPostProcessor
039 * @see ConfigurableBeanFactory#addBeanPostProcessor
040 * @see BeanFactoryPostProcessor
041 */
042public interface BeanPostProcessor {
043
044        /**
045         * Apply this BeanPostProcessor to the given new bean instance <i>before</i> any bean
046         * initialization callbacks (like InitializingBean's {@code afterPropertiesSet}
047         * or a custom init-method). The bean will already be populated with property values.
048         * The returned bean instance may be a wrapper around the original.
049         * @param bean the new bean instance
050         * @param beanName the name of the bean
051         * @return the bean instance to use, either the original or a wrapped one;
052         * if {@code null}, no subsequent BeanPostProcessors will be invoked
053         * @throws org.springframework.beans.BeansException in case of errors
054         * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet
055         */
056        Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;
057
058        /**
059         * Apply this BeanPostProcessor to the given new bean instance <i>after</i> any bean
060         * initialization callbacks (like InitializingBean's {@code afterPropertiesSet}
061         * or a custom init-method). The bean will already be populated with property values.
062         * The returned bean instance may be a wrapper around the original.
063         * <p>In case of a FactoryBean, this callback will be invoked for both the FactoryBean
064         * instance and the objects created by the FactoryBean (as of Spring 2.0). The
065         * post-processor can decide whether to apply to either the FactoryBean or created
066         * objects or both through corresponding {@code bean instanceof FactoryBean} checks.
067         * <p>This callback will also be invoked after a short-circuiting triggered by a
068         * {@link InstantiationAwareBeanPostProcessor#postProcessBeforeInstantiation} method,
069         * in contrast to all other BeanPostProcessor callbacks.
070         * @param bean the new bean instance
071         * @param beanName the name of the bean
072         * @return the bean instance to use, either the original or a wrapped one;
073         * if {@code null}, no subsequent BeanPostProcessors will be invoked
074         * @throws org.springframework.beans.BeansException in case of errors
075         * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet
076         * @see org.springframework.beans.factory.FactoryBean
077         */
078        Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;
079
080}