infra.beans.factory.SmartInitializingSingleton Maven / Gradle / Ivy
/*
* Copyright 2017 - 2024 the original author or authors.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see [https://www.gnu.org/licenses/]
*/
package infra.beans.factory;
import infra.beans.factory.config.ConfigurableBeanFactory;
import infra.beans.factory.support.AbstractBeanFactory;
/**
* 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 ConfigurableBeanFactory#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.
*
* This callback variant is somewhat similar to {@link infra.context.event.ContextStartedEvent}
* but doesn't require an implementation of {@link infra.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 BeanFactory} implementations,
* not just in an {@link infra.context.ApplicationContext} environment.
*
*
NOTE: If you intend to start/manage asynchronous tasks, preferably
* implement {@link infra.context.Lifecycle} instead which offers
* a richer model for runtime management and allows for phased startup/shutdown.
*
* @author Juergen Hoeller
* @author Harry Yang
* @see AbstractBeanFactory#preInstantiateSingletons()
* @since 4.0 2021/3/9 12:03
*/
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. {@link ConfigurableBeanFactory#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 {@link BeanFactory} bootstrap,
* and not for any other bean scope either. Carefully use it for beans
* with the intended bootstrap semantics only.
*/
default void afterSingletonsInstantiated() {
}
/**
* Invoked right at the end of the singleton pre-instantiation phase,
* with a guarantee that all regular singleton beans have been created
* already. {@link ConfigurableBeanFactory#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 {@link BeanFactory} bootstrap,
* and not for any other bean scope either. Carefully use it for beans
* with the intended bootstrap semantics only.
*/
default void afterSingletonsInstantiated(ConfigurableBeanFactory beanFactory) {
afterSingletonsInstantiated();
}
}