org.springframework.beans.factory.SmartFactoryBean Maven / Gradle / Ivy
/*
* 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
*
* 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;
/**
* Extension of the {@link FactoryBean} interface. Implementations may
* indicate whether they always return independent instances, for the
* case where their {@link #isSingleton()} implementation returning
* {@code false} does not clearly indicate independent instances.
*
* Plain {@link FactoryBean} implementations which do not implement
* this extended interface are simply assumed to always return independent
* instances if their {@link #isSingleton()} implementation returns
* {@code false}; the exposed object is only accessed on demand.
*
*
NOTE: This interface is a special purpose interface, mainly for
* internal use within the framework and within collaborating frameworks.
* In general, application-provided FactoryBeans should simply implement
* the plain {@link FactoryBean} interface. New methods might be added
* to this extended interface even in point releases.
*
* @author Juergen Hoeller
* @since 2.0.3
* @param the bean type
* @see #isPrototype()
* @see #isSingleton()
*/
public interface SmartFactoryBean extends FactoryBean {
/**
* Is the object managed by this factory a prototype? That is,
* will {@link #getObject()} always return an independent instance?
* The prototype status of the FactoryBean itself will generally
* be provided by the owning {@link BeanFactory}; usually, it has to be
* defined as singleton there.
*
This method is supposed to strictly check for independent instances;
* it should not return {@code true} for scoped objects or other
* kinds of non-singleton, non-independent objects. For this reason,
* this is not simply the inverted form of {@link #isSingleton()}.
*
The default implementation returns {@code false}.
* @return whether the exposed object is a prototype
* @see #getObject()
* @see #isSingleton()
*/
default boolean isPrototype() {
return false;
}
/**
* Does this FactoryBean expect eager initialization, that is,
* eagerly initialize itself as well as expect eager initialization
* of its singleton object (if any)?
*
A standard FactoryBean is not expected to initialize eagerly:
* Its {@link #getObject()} will only be called for actual access, even
* in case of a singleton object. Returning {@code true} from this
* method suggests that {@link #getObject()} should be called eagerly,
* also applying post-processors eagerly. This may make sense in case
* of a {@link #isSingleton() singleton} object, in particular if
* post-processors expect to be applied on startup.
*
The default implementation returns {@code false}.
* @return whether eager initialization applies
* @see org.springframework.beans.factory.config.ConfigurableListableBeanFactory#preInstantiateSingletons()
*/
default boolean isEagerInit() {
return false;
}
}