https://github.com/spring-projects/spring-framework: Spring Beans (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 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 java.beans.PropertyDescriptor;

import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValues;
import org.springframework.lang.Nullable;


Subinterface of BeanPostProcessor that adds a before-instantiation callback, and a callback after instantiation but before explicit properties are set or autowiring occurs. 
Typically used to suppress default instantiation for specific target beans,
for example to create proxies with special TargetSources (pooling targets,
lazily initializing targets, etc), or to implement additional injection strategies
such as field injection.

NOTE: This interface is a special purpose interface, mainly for internal use within the framework. It is recommended to implement the plain BeanPostProcessor interface as far as possible, or to derive from InstantiationAwareBeanPostProcessorAdapter in order to be shielded from extensions to this interface. 
Author:Juergen Hoeller, Rod Johnson
See Also:
  • setCustomTargetSourceCreators.setCustomTargetSourceCreators
  • LazyInitTargetSourceCreator
Since:1.2
/**
 * Subinterface of {@link BeanPostProcessor} that adds a before-instantiation callback,
 * and a callback after instantiation but before explicit properties are set or
 * autowiring occurs.
 *
 * <p>Typically used to suppress default instantiation for specific target beans,
 * for example to create proxies with special TargetSources (pooling targets,
 * lazily initializing targets, etc), or to implement additional injection strategies
 * such as field injection.
 *
 * <p><b>NOTE:</b> This interface is a special purpose interface, mainly for
 * internal use within the framework. It is recommended to implement the plain
 * {@link BeanPostProcessor} interface as far as possible, or to derive from
 * {@link InstantiationAwareBeanPostProcessorAdapter} in order to be shielded
 * from extensions to this interface.
 *
 * @author Juergen Hoeller
 * @author Rod Johnson
 * @since 1.2
 * @see org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator#setCustomTargetSourceCreators
 * @see org.springframework.aop.framework.autoproxy.target.LazyInitTargetSourceCreator
 */
public interface InstantiationAwareBeanPostProcessor extends BeanPostProcessor {

	
Apply this BeanPostProcessor before the target bean gets instantiated.
The returned bean object may be a proxy to use instead of the target bean,
effectively suppressing default instantiation of the target bean.

If a non-null object is returned by this method, the bean creation process will be short-circuited. The only further processing applied is the BeanPostProcessor.postProcessAfterInitialization callback from the configured BeanPostProcessors. 
This callback will only be applied to bean definitions with a bean class.
In particular, it will not be applied to beans with a factory method.

Post-processors may implement the extended SmartInstantiationAwareBeanPostProcessor interface in order to predict the type of the bean object that they are going to return here. 
The default implementation returns null. 
Params:
  • beanClass – the class of the bean to be instantiated
  • beanName – the name of the bean
Throws:
See Also:
Returns:the bean object to expose instead of a default instance of the target bean, or null to proceed with default instantiation
/**
	 * Apply this BeanPostProcessor <i>before the target bean gets instantiated</i>.
	 * The returned bean object may be a proxy to use instead of the target bean,
	 * effectively suppressing default instantiation of the target bean.
	 * <p>If a non-null object is returned by this method, the bean creation process
	 * will be short-circuited. The only further processing applied is the
	 * {@link #postProcessAfterInitialization} callback from the configured
	 * {@link BeanPostProcessor BeanPostProcessors}.
	 * <p>This callback will only be applied to bean definitions with a bean class.
	 * In particular, it will not be applied to beans with a factory method.
	 * <p>Post-processors may implement the extended
	 * {@link SmartInstantiationAwareBeanPostProcessor} interface in order
	 * to predict the type of the bean object that they are going to return here.
	 * <p>The default implementation returns {@code null}.
	 * @param beanClass the class of the bean to be instantiated
	 * @param beanName the name of the bean
	 * @return the bean object to expose instead of a default instance of the target bean,
	 * or {@code null} to proceed with default instantiation
	 * @throws org.springframework.beans.BeansException in case of errors
	 * @see #postProcessAfterInstantiation
	 * @see org.springframework.beans.factory.support.AbstractBeanDefinition#hasBeanClass
	 */
	@Nullable
	default Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
		return null;
	}

	
Perform operations after the bean has been instantiated, via a constructor or factory method,
but before Spring property population (from explicit properties or autowiring) occurs.

This is the ideal callback for performing custom field injection on the given bean
instance, right before Spring's autowiring kicks in.

The default implementation returns true. 
Params:
  • bean – the bean instance created, with properties not having been set yet
  • beanName – the name of the bean
Throws:
See Also:
Returns:true if properties should be set on the bean; false if property population should be skipped. Normal implementations should return true. Returning false will also prevent any subsequent InstantiationAwareBeanPostProcessor instances being invoked on this bean instance.
/**
	 * Perform operations after the bean has been instantiated, via a constructor or factory method,
	 * but before Spring property population (from explicit properties or autowiring) occurs.
	 * <p>This is the ideal callback for performing custom field injection on the given bean
	 * instance, right before Spring's autowiring kicks in.
	 * <p>The default implementation returns {@code true}.
	 * @param bean the bean instance created, with properties not having been set yet
	 * @param beanName the name of the bean
	 * @return {@code true} if properties should be set on the bean; {@code false}
	 * if property population should be skipped. Normal implementations should return {@code true}.
	 * Returning {@code false} will also prevent any subsequent InstantiationAwareBeanPostProcessor
	 * instances being invoked on this bean instance.
	 * @throws org.springframework.beans.BeansException in case of errors
	 * @see #postProcessBeforeInstantiation
	 */
	default boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
		return true;
	}

	
Post-process the given property values before the factory applies them
to the given bean, without any need for property descriptors.

Implementations should return null (the default) if they provide a custom postProcessPropertyValues implementation, and pvs otherwise. In a future version of this interface (with postProcessPropertyValues removed), the default implementation will return the given pvs as-is directly. 
Params:
  • pvs – the property values that the factory is about to apply (never null)
  • bean – the bean instance created, but whose properties have not yet been set
  • beanName – the name of the bean
Throws:
See Also:
Returns:the actual property values to apply to the given bean (can be the passed-in PropertyValues instance), or null which proceeds with the existing properties but specifically continues with a call to postProcessPropertyValues (requiring initialized PropertyDescriptors for the current bean class)
Since:5.1
/**
	 * Post-process the given property values before the factory applies them
	 * to the given bean, without any need for property descriptors.
	 * <p>Implementations should return {@code null} (the default) if they provide a custom
	 * {@link #postProcessPropertyValues} implementation, and {@code pvs} otherwise.
	 * In a future version of this interface (with {@link #postProcessPropertyValues} removed),
	 * the default implementation will return the given {@code pvs} as-is directly.
	 * @param pvs the property values that the factory is about to apply (never {@code null})
	 * @param bean the bean instance created, but whose properties have not yet been set
	 * @param beanName the name of the bean
	 * @return the actual property values to apply to the given bean (can be the passed-in
	 * PropertyValues instance), or {@code null} which proceeds with the existing properties
	 * but specifically continues with a call to {@link #postProcessPropertyValues}
	 * (requiring initialized {@code PropertyDescriptor}s for the current bean class)
	 * @throws org.springframework.beans.BeansException in case of errors
	 * @since 5.1
	 * @see #postProcessPropertyValues
	 */
	@Nullable
	default PropertyValues postProcessProperties(PropertyValues pvs, Object bean, String beanName)
			throws BeansException {

		return null;
	}

	
Post-process the given property values before the factory applies them
to the given bean. Allows for checking whether all dependencies have been
satisfied, for example based on a "Required" annotation on bean property setters.

Also allows for replacing the property values to apply, typically through
creating a new MutablePropertyValues instance based on the original PropertyValues,
adding or removing specific values.

The default implementation returns the given pvs as-is. 
Params:
  • pvs – the property values that the factory is about to apply (never null)
  • pds – the relevant property descriptors for the target bean (with ignored
dependency types - which the factory handles specifically - already filtered out)
  • bean – the bean instance created, but whose properties have not yet been set
  • beanName – the name of the bean
Throws:
See Also:
Returns:the actual property values to apply to the given bean (can be the passed-in PropertyValues instance), or null to skip property population
Deprecated:as of 5.1, in favor of postProcessProperties(PropertyValues, Object, String)
/**
	 * Post-process the given property values before the factory applies them
	 * to the given bean. Allows for checking whether all dependencies have been
	 * satisfied, for example based on a "Required" annotation on bean property setters.
	 * <p>Also allows for replacing the property values to apply, typically through
	 * creating a new MutablePropertyValues instance based on the original PropertyValues,
	 * adding or removing specific values.
	 * <p>The default implementation returns the given {@code pvs} as-is.
	 * @param pvs the property values that the factory is about to apply (never {@code null})
	 * @param pds the relevant property descriptors for the target bean (with ignored
	 * dependency types - which the factory handles specifically - already filtered out)
	 * @param bean the bean instance created, but whose properties have not yet been set
	 * @param beanName the name of the bean
	 * @return the actual property values to apply to the given bean (can be the passed-in
	 * PropertyValues instance), or {@code null} to skip property population
	 * @throws org.springframework.beans.BeansException in case of errors
	 * @see #postProcessProperties
	 * @see org.springframework.beans.MutablePropertyValues
	 * @deprecated as of 5.1, in favor of {@link #postProcessProperties(PropertyValues, Object, String)}
	 */
	@Deprecated
	@Nullable
	default PropertyValues postProcessPropertyValues(
			PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException {

		return pvs;
	}

}