org.springframework.beans.factory.config
Class AbstractFactoryBean

java.lang.Object
  org.springframework.beans.factory.config.AbstractFactoryBean

All Implemented Interfaces:

DisposableBean, FactoryBean, InitializingBean

Direct Known Subclasses:

ListFactoryBean, MapFactoryBean, ObjectFactoryCreatingFactoryBean, SetFactoryBean

public abstract class AbstractFactoryBean
extends Object
implements FactoryBean, InitializingBean, DisposableBean

Simple template superclass for 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:

setSingleton(boolean), createInstance()

Field Summary

protected Log

logger Logger available to subclasses

Constructor Summary

AbstractFactoryBean()

Method Summary

void	afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
protected abstract Object	createInstance() Template method that subclasses must override to construct the object returned by this factory.
void	destroy() Invoked by a BeanFactory on destruction of a singleton.
protected void	destroyInstance(Object instance) Callback for destroying a singleton instance.
Object	getObject() Return an instance (possibly shared or independent) of the object managed by this factory.
boolean	isSingleton() Is the bean managed by this factory a singleton or a prototype?
void	setSingleton(boolean singleton) Set if a singleton should be created, or a new object on each request else.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.beans.factory.FactoryBean

getObjectType

Field Detail

logger

protected final Log logger

Logger available to subclasses

Constructor Detail

AbstractFactoryBean

public AbstractFactoryBean()

Method Detail

setSingleton

public void setSingleton(boolean singleton)

Set if a singleton should be created, or a new object on each request else. Default is "true" (a singleton).

isSingleton

public boolean isSingleton()

Description copied from interface: FactoryBean

Is the bean managed by this factory a singleton or a prototype? That is, will 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.

Specified by:

isSingleton in interface FactoryBean

Returns:

if this bean is a singleton

See Also:

FactoryBean.getObject()

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Description copied from interface: InitializingBean

Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

Specified by:

afterPropertiesSet in interface InitializingBean

Throws:

Exception - in the event of misconfiguration (such as failure to set an essential property) or if initialization fails.

getObject

public final Object getObject()
                       throws Exception

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 method returns null, the factory will consider the FactoryBean as not fully initialized and throw a corresponding FactoryBeanNotInitializedException.

Specified by:

getObject in interface FactoryBean

Returns:

an instance of the bean (should not be null; a null value will be considered as an indication of incomplete initialization)

Throws:

Exception - in case of creation errors

See Also:

FactoryBeanNotInitializedException

destroy

public void destroy()
             throws Exception

Description copied from interface: DisposableBean

Invoked by a BeanFactory on destruction of a singleton.

Specified by:

destroy in interface DisposableBean

Throws:

Exception - in case of shutdown errors. Exceptions will get logged but not rethrown to allow other beans to release their resources too.

createInstance

protected abstract Object createInstance()
                                  throws Exception

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 occured during object creation

See Also:

getObject()

destroyInstance

protected void destroyInstance(Object instance)
                        throws Exception

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 by createInstance()

Throws:

Exception - in case of shutdown errors

See Also:

createInstance()