@Deprecated public class BeanReferenceFactoryBean extends Object implements SmartFactoryBean<Object>, BeanFactoryAware
Usually, the target bean will reside in a different bean definition file, using this FactoryBean to link it in and expose it under a different name. Effectively, this corresponds to an alias for the target bean.
NOTE: For XML bean definition files, an
tag is available that effectively achieves the same.
A special capability of this FactoryBean is enabled through its configuration
as bean definition: The "targetBeanName" can be substituted through a placeholder,
in combination with Spring's
Thanks to Marcus Bristav for pointing this out!
|Constructor and Description|
|Modifier and Type||Method and Description|
Return an instance (possibly shared or independent) of the object managed by this factory.
Return the type of object that this FactoryBean creates, or
Does this FactoryBean expect eager initialization, that is, eagerly initialize itself as well as expect eager initialization of its singleton object (if any)?
Is the object managed by this factory a prototype? That is, will
Is the object managed by this factory a singleton? That is, will
Callback that supplies the owning factory to a bean instance.
Set the name of the target bean.
public void setTargetBeanName(String targetBeanName)
This property is required. The value for this property can be substituted through a placeholder, in combination with Spring's PropertyPlaceholderConfigurer.
targetBeanName- the name of the target bean
public void setBeanFactory(BeanFactory beanFactory)
Invoked after the population of normal bean properties
but before an initialization callback such as
InitializingBean.afterPropertiesSet() or a custom init-method.
public Object getObject() throws BeansException
As with a
BeanFactory, this allows support for both the
Singleton and Prototype design pattern.
If this FactoryBean is not fully initialized yet at the time of
the call (for example because it is involved in a circular reference),
throw a corresponding
As of Spring 2.0, FactoryBeans are allowed to return
objects. The factory will consider this as normal value to be used; it
will not throw a FactoryBeanNotInitializedException in this case anymore.
FactoryBean implementations are encouraged to throw
FactoryBeanNotInitializedException themselves now, as appropriate.
public Class<?> getObjectType()
nullif not known in advance.
This allows one to check for specific types of beans without instantiating objects, for example on autowiring.
In the case of implementations that are creating a singleton object, this method should try to avoid singleton creation as far as possible; it should rather estimate the type in advance. For prototypes, returning a meaningful type here is advisable too.
This method can be called before this FactoryBean has been fully initialized. It must not rely on state created during initialization; of course, it can still use such state if available.
NOTE: Autowiring will simply ignore FactoryBeans that return
null here. Therefore it is highly recommended to implement
this method properly, using the current state of the FactoryBean.
nullif not known at the time of the call
public boolean isSingleton()
FactoryBean.getObject()always return the same object (a reference that can be cached)?
NOTE: If a FactoryBean indicates to hold a singleton object,
the object returned from
getObject() might get cached
by the owning BeanFactory. Hence, do not return
unless the FactoryBean always exposes the same reference.
The singleton status of the FactoryBean itself will generally be provided by the owning BeanFactory; usually, it has to be defined as singleton there.
NOTE: This method returning
false does not
necessarily indicate that returned objects are independent instances.
An implementation of the extended
may explicitly indicate independent instances through its
SmartFactoryBean.isPrototype() method. Plain
implementations which do not implement this extended interface are
simply assumed to always return independent instances if the
isSingleton() implementation returns
public boolean isPrototype()
FactoryBean.getObject()always return an independent instance?
The prototype status of the FactoryBean itself will generally
be provided by the owning
BeanFactory; usually, it has to be
defined as singleton there.
This method is supposed to strictly check for independent instances;
it should not return
true for scoped objects or other
kinds of non-singleton, non-independent objects. For this reason,
this is not simply the inverted form of
public boolean isEagerInit()
A standard FactoryBean is not expected to initialize eagerly:
FactoryBean.getObject() will only be called for actual access, even
in case of a singleton object. Returning
true from this
method suggests that
FactoryBean.getObject() should be called eagerly,
also applying post-processors eagerly. This may make sense in case
singleton object, in particular if
post-processors expect to be applied on startup.