org.springframework.web.context.support
Class ServletContextFactoryBean

java.lang.Object
  extended by org.springframework.web.context.support.ServletContextFactoryBean
All Implemented Interfaces:
FactoryBean, ServletContextAware

public class ServletContextFactoryBean
extends Object
implements FactoryBean, ServletContextAware

Simple FactoryBean that exposes the ServletContext for bean references. Can be used as alternative to implementing the ServletContextAware callback interface. Allows for passing the ServletContext reference to a constructor argument or any custom bean property.

Note that there's a special FactoryBean for exposing a specific ServletContext attribute, named ServletContextAttributeFactoryBean. So if all you need from the ServletContext is access to a specific attribute, ServletContextAttributeFactoryBean allows you to expose a constructor argument or bean property of the attribute type, which is a preferable to a dependency on the full ServletContext.

Since:
1.1.4
Author:
Juergen Hoeller
See Also:
ServletContext, ServletContextAware, ServletContextAttributeFactoryBean

Constructor Summary
ServletContextFactoryBean()
           
 
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 object managed by this factory a singleton?
 void setServletContext(ServletContext servletContext)
          Set the ServletContext that this object runs in.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ServletContextFactoryBean

public ServletContextFactoryBean()
Method Detail

setServletContext

public void setServletContext(ServletContext servletContext)
Description copied from interface: ServletContextAware
Set the ServletContext 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's setApplicationContext.

Specified by:
setServletContext in interface ServletContextAware
Parameters:
servletContext - ServletContext object to be used by this object
See Also:
InitializingBean.afterPropertiesSet(), ApplicationContextAware.setApplicationContext(org.springframework.context.ApplicationContext)

getObject

public Object 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 interface FactoryBean
Returns:
an instance of the bean (can be null)
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 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 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 object managed by this factory a singleton? That is, will 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 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.

Specified by:
isSingleton in interface FactoryBean
Returns:
whether the exposed object is a singleton
See Also:
FactoryBean.getObject(), SmartFactoryBean.isPrototype()


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