org.springframework.aop.scope

Class ScopedProxyFactoryBean

java.lang.Object

org.springframework.aop.framework.ProxyConfig

org.springframework.aop.scope.ScopedProxyFactoryBean

All Implemented Interfaces:

java.io.Serializable, AopInfrastructureBean, Aware, BeanFactoryAware, FactoryBean<java.lang.Object>

public class ScopedProxyFactoryBean
extends ProxyConfig
implements FactoryBean<java.lang.Object>, BeanFactoryAware, AopInfrastructureBean

Convenient proxy factory bean for scoped objects.

Proxies created using this factory bean are thread-safe singletons and may be injected into shared objects, with transparent scoping behavior.

Proxies returned by this class implement the ScopedObject interface. This presently allows for removing the corresponding object from the scope, seamlessly creating a new instance in the scope on next access.

Please note that the proxies created by this factory are class-based proxies by default. This can be customized through switching the "proxyTargetClass" property to "false".

Since:

2.0

Author:

Rod Johnson, Juergen Hoeller

See Also:

ProxyConfig.setProxyTargetClass(boolean), Serialized Form

Constructor Summary

Constructors

Constructor and Description
ScopedProxyFactoryBean() Create a new ScopedProxyFactoryBean instance.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	getObject() Return an instance (possibly shared or independent) of the object managed by this factory.
java.lang.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? That is, will FactoryBean.getObject() always return the same object (a reference that can be cached)?
void	setBeanFactory(BeanFactory beanFactory) Callback that supplies the owning factory to a bean instance.
void	setTargetBeanName(java.lang.String targetBeanName) Set the name of the bean that is to be scoped.

Methods inherited from class org.springframework.aop.framework.ProxyConfig

copyFrom, isExposeProxy, isFrozen, isOpaque, isOptimize, isProxyTargetClass, setExposeProxy, setFrozen, setOpaque, setOptimize, setProxyTargetClass, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ScopedProxyFactoryBean

public ScopedProxyFactoryBean()

Create a new ScopedProxyFactoryBean instance.

Method Detail

setTargetBeanName

public void setTargetBeanName(java.lang.String targetBeanName)

Set the name of the bean that is to be scoped.

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 java.lang.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<java.lang.Object>

Returns:

an instance of the bean (can be null)

See Also:

FactoryBeanNotInitializedException

getObjectType

public java.lang.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<java.lang.Object>

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.

The default implementation returns true, since a FactoryBean typically manages a singleton instance.

Specified by:

isSingleton in interface FactoryBean<java.lang.Object>

Returns:

whether the exposed object is a singleton

See Also:

FactoryBean.getObject(), SmartFactoryBean.isPrototype()