001/*
002 * Copyright 2002-2012 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 java.lang.reflect.Constructor;
020
021import org.springframework.beans.BeansException;
022
023/**
024 * Extension of the {@link InstantiationAwareBeanPostProcessor} interface,
025 * adding a callback for predicting the eventual type of a processed bean.
026 *
027 * <p><b>NOTE:</b> This interface is a special purpose interface, mainly for
028 * internal use within the framework. In general, application-provided
029 * post-processors should simply implement the plain {@link BeanPostProcessor}
030 * interface or derive from the {@link InstantiationAwareBeanPostProcessorAdapter}
031 * class. New methods might be added to this interface even in point releases.
032 *
033 * @author Juergen Hoeller
034 * @since 2.0.3
035 * @see InstantiationAwareBeanPostProcessorAdapter
036 */
037public interface SmartInstantiationAwareBeanPostProcessor extends InstantiationAwareBeanPostProcessor {
038
039        /**
040         * Predict the type of the bean to be eventually returned from this
041         * processor's {@link #postProcessBeforeInstantiation} callback.
042         * @param beanClass the raw class of the bean
043         * @param beanName the name of the bean
044         * @return the type of the bean, or {@code null} if not predictable
045         * @throws org.springframework.beans.BeansException in case of errors
046         */
047        Class<?> predictBeanType(Class<?> beanClass, String beanName) throws BeansException;
048
049        /**
050         * Determine the candidate constructors to use for the given bean.
051         * @param beanClass the raw class of the bean (never {@code null})
052         * @param beanName the name of the bean
053         * @return the candidate constructors, or {@code null} if none specified
054         * @throws org.springframework.beans.BeansException in case of errors
055         */
056        Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName) throws BeansException;
057
058        /**
059         * Obtain a reference for early access to the specified bean,
060         * typically for the purpose of resolving a circular reference.
061         * <p>This callback gives post-processors a chance to expose a wrapper
062         * early - that is, before the target bean instance is fully initialized.
063         * The exposed object should be equivalent to the what
064         * {@link #postProcessBeforeInitialization} / {@link #postProcessAfterInitialization}
065         * would expose otherwise. Note that the object returned by this method will
066         * be used as bean reference unless the post-processor returns a different
067         * wrapper from said post-process callbacks. In other words: Those post-process
068         * callbacks may either eventually expose the same reference or alternatively
069         * return the raw bean instance from those subsequent callbacks (if the wrapper
070         * for the affected bean has been built for a call to this method already,
071         * it will be exposes as final bean reference by default).
072         * @param bean the raw bean instance
073         * @param beanName the name of the bean
074         * @return the object to expose as bean reference
075         * (typically with the passed-in bean instance as default)
076         * @throws org.springframework.beans.BeansException in case of errors
077         */
078        Object getEarlyBeanReference(Object bean, String beanName) throws BeansException;
079
080}