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java.lang.Objectorg.springframework.beans.factory.config.BeanReferenceFactoryBean
public class BeanReferenceFactoryBean
FactoryBean that exposes an arbitrary target bean under a different name.
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 <alias>
 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 PropertyPlaceholderConfigurer.
 Thanks to Marcus Bristav for pointing this out!
setTargetBeanName(java.lang.String), 
PropertyPlaceholderConfigurer| Constructor Summary | |
|---|---|
| BeanReferenceFactoryBean() | |
| Method Summary | |
|---|---|
|  Object | getObject()Return an instance (possibly shared or independent) of the object managed by this factory. | 
|  Class | getObjectType()Return the type of object that this FactoryBean creates, or nullif not known in advance. | 
|  boolean | isEagerInit()Does this FactoryBean expect eager initialization, that is, eagerly initialize itself as well as expect eager initialization of its singleton object (if any)? | 
|  boolean | isPrototype()Is the object managed by this factory a prototype? | 
|  boolean | isSingleton()Is the object managed by this factory a singleton? | 
|  void | setBeanFactory(BeanFactory beanFactory)Callback that supplies the owning factory to a bean instance. | 
|  void | setTargetBeanName(String targetBeanName)Set the name of the target bean. | 
| Methods inherited from class java.lang.Object | 
|---|
| clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait | 
| Constructor Detail | 
|---|
public BeanReferenceFactoryBean()
| Method Detail | 
|---|
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 beanPropertyPlaceholderConfigurerpublic void setBeanFactory(BeanFactory beanFactory)
BeanFactoryAwareInvoked after the population of normal bean properties
 but before an initialization callback such as
 InitializingBean.afterPropertiesSet() or a custom init-method.
setBeanFactory in interface BeanFactoryAwarebeanFactory - owning BeanFactory (never null).
 The bean can immediately call methods on the factory.BeanInitializationException
public Object getObject()
                 throws BeansException
FactoryBeanAs 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 FactoryBeanNotInitializedException.
 
As of Spring 2.0, FactoryBeans are allowed to return null
 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.
getObject in interface FactoryBeannull)
BeansExceptionFactoryBeanNotInitializedExceptionpublic Class getObjectType()
FactoryBeannull if 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.
getObjectType in interface FactoryBeannull if not known at the time of the callListableBeanFactory.getBeansOfType(java.lang.Class)public boolean isSingleton()
FactoryBeanFactoryBean.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 true
 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 SmartFactoryBean interface
 may explicitly indicate independent instances through its
 SmartFactoryBean.isPrototype() method. Plain FactoryBean
 implementations which do not implement this extended interface are
 simply assumed to always return independent instances if the
 isSingleton() implementation returns false.
isSingleton in interface FactoryBeanFactoryBean.getObject(), 
SmartFactoryBean.isPrototype()public boolean isPrototype()
SmartFactoryBeanFactoryBean.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 FactoryBean.isSingleton().
isPrototype in interface SmartFactoryBeanFactoryBean.getObject(), 
FactoryBean.isSingleton()public boolean isEagerInit()
SmartFactoryBeanA standard FactoryBean is not expected to initialize eagerly:
 Its 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
 of a singleton object, in particular if
 post-processors expect to be applied on startup.
isEagerInit in interface SmartFactoryBeanConfigurableListableBeanFactory.preInstantiateSingletons()| 
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