/*
 * Copyright 2002-2014 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
 *
 *      https://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;

Callback interface triggered at the end of the singleton pre-instantiation phase during BeanFactory bootstrap. This interface can be implemented by singleton beans in order to perform some initialization after the regular singleton instantiation algorithm, avoiding side effects with accidental early initialization (e.g. from ListableBeanFactory.getBeansOfType calls). In that sense, it is an alternative to InitializingBean which gets triggered right at the end of a bean's local construction phase. 
This callback variant is somewhat similar to ContextRefreshedEvent but doesn't require an implementation of ApplicationListener, with no need to filter context references across a context hierarchy etc. It also implies a more minimal dependency on just the beans package and is being honored by standalone ListableBeanFactory implementations, not just in an ApplicationContext environment. 
NOTE: If you intend to start/manage asynchronous tasks, preferably implement Lifecycle instead which offers a richer model for runtime management and allows for phased startup/shutdown. 
Author:
Juergen Hoeller
See Also:
ConfigurableListableBeanFactory.preInstantiateSingletons()
Since:
4.1/**
 * Callback interface triggered at the end of the singleton pre-instantiation phase
 * during {@link BeanFactory} bootstrap. This interface can be implemented by
 * singleton beans in order to perform some initialization after the regular
 * singleton instantiation algorithm, avoiding side effects with accidental early
 * initialization (e.g. from {@link ListableBeanFactory#getBeansOfType} calls).
 * In that sense, it is an alternative to {@link InitializingBean} which gets
 * triggered right at the end of a bean's local construction phase.
 *
 * <p>This callback variant is somewhat similar to
 * {@link org.springframework.context.event.ContextRefreshedEvent} but doesn't
 * require an implementation of {@link org.springframework.context.ApplicationListener},
 * with no need to filter context references across a context hierarchy etc.
 * It also implies a more minimal dependency on just the {@code beans} package
 * and is being honored by standalone {@link ListableBeanFactory} implementations,
 * not just in an {@link org.springframework.context.ApplicationContext} environment.
 *
 * <p><b>NOTE:</b> If you intend to start/manage asynchronous tasks, preferably
 * implement {@link org.springframework.context.Lifecycle} instead which offers
 * a richer model for runtime management and allows for phased startup/shutdown.
 *
 * @author Juergen Hoeller
 * @since 4.1
 * @see org.springframework.beans.factory.config.ConfigurableListableBeanFactory#preInstantiateSingletons()
 */
public interface SmartInitializingSingleton {

	
Invoked right at the end of the singleton pre-instantiation phase, with a guarantee that all regular singleton beans have been created already. ListableBeanFactory.getBeansOfType calls within this method won't trigger accidental side effects during bootstrap. 
NOTE: This callback won't be triggered for singleton beans lazily initialized on demand after BeanFactory bootstrap, and not for any other bean scope either. Carefully use it for beans with the intended bootstrap semantics only. /**
	 * Invoked right at the end of the singleton pre-instantiation phase,
	 * with a guarantee that all regular singleton beans have been created
	 * already. {@link ListableBeanFactory#getBeansOfType} calls within
	 * this method won't trigger accidental side effects during bootstrap.
	 * <p><b>NOTE:</b> This callback won't be triggered for singleton beans
	 * lazily initialized on demand after {@link BeanFactory} bootstrap,
	 * and not for any other bean scope either. Carefully use it for beans
	 * with the intended bootstrap semantics only.
	 */
	void afterSingletonsInstantiated();

}