org.springframework.web.context.support

Class ServletContextParameterFactoryBean

java.lang.Object

org.springframework.web.context.support.ServletContextParameterFactoryBean

All Implemented Interfaces:

Aware, FactoryBean<String>, ServletContextAware

public class ServletContextParameterFactoryBean
extends Object
implements FactoryBean<String>, ServletContextAware

FactoryBean that retrieves a specific ServletContext init parameter (that is, a "context-param" defined in web.xml). Exposes that ServletContext init parameter when used as bean reference, effectively making it available as named Spring bean instance.

NOTE: As of Spring 3.0, you may also use the "contextParameters" default bean which is of type Map, and dereference it using an "#{contextParameters.myKey}" expression to access a specific parameter by name.

Since:

1.2.4

Author:

Juergen Hoeller

See Also:

WebApplicationContext.CONTEXT_PARAMETERS_BEAN_NAME, ServletContextAttributeFactoryBean

Constructor Summary

Constructors

Constructor and Description
ServletContextParameterFactoryBean()

Method Summary

Methods

Modifier and Type	Method and Description
String	getObject() Return an instance (possibly shared or independent) of the object managed by this factory.
Class<String>	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? That is, will FactoryBean.getObject() always return the same object (a reference that can be cached)?
void	setInitParamName(String initParamName) Set the name of the ServletContext init parameter to expose.
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

ServletContextParameterFactoryBean

public ServletContextParameterFactoryBean()

Method Detail

setInitParamName

public void setInitParamName(String initParamName)

Set the name of the ServletContext init parameter to expose.

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 String 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<String>

Returns:

an instance of the bean (can be null)

See Also:

FactoryBeanNotInitializedException

getObjectType

public Class<String> 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<String>

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<T>)

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<String>

Returns:

whether the exposed object is a singleton

See Also:

FactoryBean.getObject(), SmartFactoryBean.isPrototype()