Class ServletContextAttributeFactoryBean
- All Implemented Interfaces:
Aware
,FactoryBean<Object>
,ServletContextAware
FactoryBean
that fetches a specific, existing ServletContext attribute.
Exposes that ServletContext attribute when used as bean reference,
effectively making it available as named Spring bean instance.
Intended to link in ServletContext attributes that exist before the startup of the Spring application context. Typically, such attributes will have been put there by third-party web frameworks. In a purely Spring-based web application, no such linking in of ServletContext attributes will be necessary.
NOTE: You may also use the "contextAttributes" default bean, which is of type Map, and dereference it using a "#{contextAttributes.myKey}" expression to access a specific attribute by name.
- Since:
- 1.1.4
- Author:
- Juergen Hoeller
- See Also:
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Field Summary
Fields inherited from interface org.springframework.beans.factory.FactoryBean
OBJECT_TYPE_ATTRIBUTE
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionReturn an instance (possibly shared or independent) of the object managed by this factory.Class<?>
Return the type of object that this FactoryBean creates, ornull
if not known in advance.boolean
Is the object managed by this factory a singleton? That is, willFactoryBean.getObject()
always return the same object (a reference that can be cached)?void
setAttributeName
(String attributeName) Set the name of the ServletContext attribute to expose.void
setServletContext
(ServletContext servletContext) Set theServletContext
that this object runs in.
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Constructor Details
-
ServletContextAttributeFactoryBean
public ServletContextAttributeFactoryBean()
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Method Details
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setAttributeName
Set the name of the ServletContext attribute to expose. -
setServletContext
Description copied from interface:ServletContextAware
Set theServletContext
that this object runs in.Invoked after population of normal bean properties but before an init callback like InitializingBean's
afterPropertiesSet
or a custom init-method. Invoked after ApplicationContextAware'ssetApplicationContext
.- Specified by:
setServletContext
in interfaceServletContextAware
- Parameters:
servletContext
- the ServletContext object to be used by this object- See Also:
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getObject
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 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.- Specified by:
getObject
in interfaceFactoryBean<Object>
- Returns:
- an instance of the bean (can be
null
) - Throws:
Exception
- in case of creation errors- See Also:
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getObjectType
Description copied from interface:FactoryBean
Return the type of object that this FactoryBean creates, ornull
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.- Specified by:
getObjectType
in interfaceFactoryBean<Object>
- Returns:
- the type of object that this FactoryBean creates,
or
null
if not known at the time of the call - See Also:
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isSingleton
public boolean isSingleton()Description copied from interface:FactoryBean
Is the object managed by this factory a singleton? That is, willFactoryBean.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 returntrue
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 extendedSmartFactoryBean
interface may explicitly indicate independent instances through itsSmartFactoryBean.isPrototype()
method. PlainFactoryBean
implementations which do not implement this extended interface are simply assumed to always return independent instances if theisSingleton()
implementation returnsfalse
.The default implementation returns
true
, since aFactoryBean
typically manages a singleton instance.- Specified by:
isSingleton
in interfaceFactoryBean<Object>
- Returns:
- whether the exposed object is a singleton
- See Also:
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