org.springframework.beans.factory.FactoryBean Maven / Gradle / Ivy
/*
* Copyright 2002-2004 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;
/**
* Interface to be implemented by objects used within a BeanFactory
* that are themselves factories. If a bean implements this interface,
* it is used as a factory, not directly as a bean.
*
* NB: A bean that implements this interface cannot be used
* as a normal bean.
*
*
FactoryBeans can support singletons and prototypes.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since March 08, 2003
* @see org.springframework.beans.factory.BeanFactory
*/
public interface FactoryBean {
/**
* Return an instance (possibly shared or independent) of the object
* managed by this factory. As with a BeanFactory, this allows
* support for both the Singleton and Prototype design pattern.
* @return an instance of the bean (should never be null)
* @throws Exception in case of creation errors
*/
Object getObject() throws Exception;
/**
* Return the type of object that this FactoryBean creates, or null
* if not known in advance. This allows to check for specific types of
* beans without instantiating objects, e.g. on autowiring.
*
For a singleton, this can simply return getObject().getClass(),
* or even null, as autowiring will always check the actual objects
* for singletons. For prototypes, returning a meaningful type here
* is highly advisable, as autowiring will simply ignore them else.
* @return the type of object that this FactoryBean creates, or null
* @see ListableBeanFactory#getBeansOfType
*/
Class getObjectType();
/**
* Is the bean managed by this factory a singleton or a prototype?
* That is, will getObject() always return the same object?
*
The singleton status of the FactoryBean itself will
* generally be provided by the owning BeanFactory.
* @return if this bean is a singleton
*/
boolean isSingleton();
}