org.springframework.beans.factory.config
Class BeanReferenceFactoryBean

java.lang.Object
  extended by org.springframework.beans.factory.config.BeanReferenceFactoryBean
All Implemented Interfaces:
BeanFactoryAware, FactoryBean

public class BeanReferenceFactoryBean
extends Object
implements FactoryBean, BeanFactoryAware

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, a <alias> tag is available that effectively achieves the same.

Since:
1.2
Author:
Juergen Hoeller

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 null if not known in advance.
 boolean isSingleton()
          Is the bean managed by this factory a singleton or a prototype?
 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, potentially in a different bean definition file.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BeanReferenceFactoryBean

public BeanReferenceFactoryBean()
Method Detail

setTargetBeanName

public void setTargetBeanName(String targetBeanName)
Set the name of the target bean, potentially in a different bean definition file.


setBeanFactory

public void setBeanFactory(BeanFactory beanFactory)
Description copied from interface: BeanFactoryAware
Callback that supplies the owning factory to a bean instance.

Invoked after the population of normal bean properties but before an initialization callback such as InitializingBean.afterPropertiesSet() or a custom init-method.

Specified by:
setBeanFactory in interface BeanFactoryAware
Parameters:
beanFactory - owning BeanFactory (never null). The bean can immediately call methods on the factory.
See Also:
BeanInitializationException

getObject

public Object getObject()
                 throws BeansException
Description copied from 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.

If this method returns null, the factory will consider the FactoryBean as not fully initialized and throw a corresponding FactoryBeanNotInitializedException.

Specified by:
getObject in interface FactoryBean
Returns:
an instance of the bean (should not be null; a null value will be considered as an indication of incomplete initialization)
Throws:
BeansException
See Also:
FactoryBeanNotInitializedException

getObjectType

public Class getObjectType()
Description copied from interface: FactoryBean
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, for example on autowiring.

For a singleton, this 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.

Specified by:
getObjectType in interface FactoryBean
Returns:
the type of object that this FactoryBean creates, or null if not known at the time of the call
See Also:
ListableBeanFactory.getBeansOfType(java.lang.Class)

isSingleton

public boolean isSingleton()
Description copied from interface: FactoryBean
Is the bean managed by this factory a singleton or a prototype? That is, will 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.

Specified by:
isSingleton in interface FactoryBean
Returns:
if this bean is a singleton
See Also:
FactoryBean.getObject()


Copyright (c) 2002-2007 The Spring Framework Project.