Class AbstractFactoryBean<T>
- Type Parameters:
T
- the bean type
- All Implemented Interfaces:
Aware
,BeanClassLoaderAware
,BeanFactoryAware
,DisposableBean
,FactoryBean<T>
,InitializingBean
- Direct Known Subclasses:
AbstractServiceLoaderBasedFactoryBean
,ListFactoryBean
,MapFactoryBean
,ObjectFactoryCreatingFactoryBean
,ProviderCreatingFactoryBean
,SetFactoryBean
,SortedResourcesFactoryBean
FactoryBean
implementations that
creates a singleton or a prototype object, depending on a flag.
If the "singleton" flag is true
(the default),
this class will create the object that it creates exactly once
on initialization and subsequently return said singleton instance
on all calls to the getObject()
method.
Else, this class will create a new instance every time the
getObject()
method is invoked. Subclasses are responsible
for implementing the abstract createInstance()
template
method to actually create the object(s) to expose.
- Since:
- 1.0.2
- Author:
- Juergen Hoeller, Keith Donald
- 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 TypeMethodDescriptionvoid
Eagerly create the singleton instance, if necessary.protected abstract T
Template method that subclasses must override to construct the object returned by this factory.void
destroy()
Destroy the singleton instance, if any.protected void
destroyInstance
(T instance) Callback for destroying a singleton instance.protected BeanFactory
Return the BeanFactory that this bean runs in.protected TypeConverter
Obtain a bean type converter from the BeanFactory that this bean runs in.protected Class<?>[]
Return an array of interfaces that a singleton object exposed by this FactoryBean is supposed to implement, for use with an 'early singleton proxy' that will be exposed in case of a circular reference.final T
Expose the singleton instance or create a new prototype instance.abstract Class<?>
This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.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
setBeanClassLoader
(ClassLoader classLoader) Callback that supplies the beanclass loader
to a bean instance.void
setBeanFactory
(BeanFactory beanFactory) Callback that supplies the owning factory to a bean instance.void
setSingleton
(boolean singleton) Set if a singleton should be created, or a new object on each request otherwise.
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Field Details
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logger
Logger available to subclasses.
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Constructor Details
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AbstractFactoryBean
public AbstractFactoryBean()
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Method Details
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setSingleton
public void setSingleton(boolean singleton) Set if a singleton should be created, or a new object on each request otherwise. Default istrue
(a singleton). -
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<T>
- Returns:
- whether the exposed object is a singleton
- See Also:
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setBeanClassLoader
Description copied from interface:BeanClassLoaderAware
Callback that supplies the beanclass loader
to a bean instance.Invoked after the population of normal bean properties but before an initialization callback such as
InitializingBean's
InitializingBean.afterPropertiesSet()
method or a custom init-method.- Specified by:
setBeanClassLoader
in interfaceBeanClassLoaderAware
- Parameters:
classLoader
- the owning class loader
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setBeanFactory
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 interfaceBeanFactoryAware
- Parameters:
beanFactory
- owning BeanFactory (nevernull
). The bean can immediately call methods on the factory.- See Also:
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getBeanFactory
Return the BeanFactory that this bean runs in. -
getBeanTypeConverter
Obtain a bean type converter from the BeanFactory that this bean runs in. This is typically a fresh instance for each call, since TypeConverters are usually not thread-safe.Falls back to a SimpleTypeConverter when not running in a BeanFactory.
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afterPropertiesSet
Eagerly create the singleton instance, if necessary.- Specified by:
afterPropertiesSet
in interfaceInitializingBean
- Throws:
Exception
- in the event of misconfiguration (such as failure to set an essential property) or if initialization fails for any other reason
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getObject
Expose the singleton instance or create a new prototype instance.- Specified by:
getObject
in interfaceFactoryBean<T>
- Returns:
- an instance of the bean (can be
null
) - Throws:
Exception
- in case of creation errors- See Also:
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destroy
Destroy the singleton instance, if any.- Specified by:
destroy
in interfaceDisposableBean
- Throws:
Exception
- in case of shutdown errors. Exceptions will get logged but not rethrown to allow other beans to release their resources as well.- See Also:
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getObjectType
This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.- Specified by:
getObjectType
in interfaceFactoryBean<T>
- 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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createInstance
Template method that subclasses must override to construct the object returned by this factory.Invoked on initialization of this FactoryBean in case of a singleton; else, on each
getObject()
call.- Returns:
- the object returned by this factory
- Throws:
Exception
- if an exception occurred during object creation- See Also:
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getEarlySingletonInterfaces
Return an array of interfaces that a singleton object exposed by this FactoryBean is supposed to implement, for use with an 'early singleton proxy' that will be exposed in case of a circular reference.The default implementation returns this FactoryBean's object type, provided that it is an interface, or
null
otherwise. The latter indicates that early singleton access is not supported by this FactoryBean. This will lead to a FactoryBeanNotInitializedException getting thrown.- Returns:
- the interfaces to use for 'early singletons',
or
null
to indicate a FactoryBeanNotInitializedException - See Also:
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destroyInstance
Callback for destroying a singleton instance. Subclasses may override this to destroy the previously created instance.The default implementation is empty.
- Parameters:
instance
- the singleton instance, as returned bycreateInstance()
- Throws:
Exception
- in case of shutdown errors- See Also:
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