AbstractFactoryBean

java.lang.Object
- org.springframework.beans.factory.config.AbstractFactoryBean<T>

All Implemented Interfaces:

Aware, BeanClassLoaderAware, BeanFactoryAware, DisposableBean, FactoryBean<T>, InitializingBean

Direct Known Subclasses:

AbstractServiceLoaderBasedFactoryBean, ListFactoryBean, MapFactoryBean, ObjectFactoryCreatingFactoryBean, ProviderCreatingFactoryBean, SetFactoryBean, SortedResourcesFactoryBean
```
public abstract class AbstractFactoryBean<T>
extends java.lang.Object
implements FactoryBean<T>, BeanClassLoaderAware, BeanFactoryAware, 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()

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`private class`	`AbstractFactoryBean.EarlySingletonInvocationHandler` Reflective InvocationHandler for lazy access to the actual singleton object.

Field Summary

Fields
Modifier and Type	Field and Description
`private java.lang.ClassLoader`	`beanClassLoader`
`private BeanFactory`	`beanFactory`
`private T`	`earlySingletonInstance`
`private boolean`	`initialized`
`protected Log`	`logger` Logger available to subclasses
`private boolean`	`singleton`
`private T`	`singletonInstance`

Constructor Summary

Constructors
Constructor and Description

AbstractFactoryBean()

Constructors
Constructor and Description
`AbstractFactoryBean()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`afterPropertiesSet()` Eagerly create the singleton instance, if necessary.
`protected abstract T`	`createInstance()` 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`	`getBeanFactory()` Return the BeanFactory that this bean runs in.
`protected TypeConverter`	`getBeanTypeConverter()` Obtain a bean type converter from the BeanFactory that this bean runs in.
`private T`	`getEarlySingletonInstance()` Determine an 'eager singleton' instance, exposed in case of a circular reference.
`protected java.lang.Class<?>[]`	`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.
`T`	`getObject()` Expose the singleton instance or create a new prototype instance.
`abstract java.lang.Class<?>`	`getObjectType()` This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.
`private T`	`getSingletonInstance()` Expose the singleton instance (for access through the 'early singleton' proxy).
`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`	`setBeanClassLoader(java.lang.ClassLoader classLoader)` Callback that supplies the bean `class 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.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - logger
```
protected final Log logger
```
    Logger available to subclasses
  - singleton
```
private boolean singleton
```
  - beanClassLoader
```
private java.lang.ClassLoader beanClassLoader
```
  - beanFactory
```
private BeanFactory beanFactory
```
  - initialized
```
private boolean initialized
```
  - singletonInstance
```
private T singletonInstance
```
  - earlySingletonInstance
```
private T earlySingletonInstance
```
- 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 otherwise. Default is true (a singleton).
  - 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<T>
    
    Returns:
    
    whether the exposed object is a singleton
    
    See Also:
    
    FactoryBean.getObject(), SmartFactoryBean.isPrototype()
  - setBeanClassLoader
```
public void setBeanClassLoader(java.lang.ClassLoader classLoader)
```
    Description copied from interface: BeanClassLoaderAware
    
    Callback that supplies the bean class 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 interface BeanClassLoaderAware
    
    Parameters:
    
    classLoader - the owning class loader; may be null in which case a default ClassLoader must be used, for example the ClassLoader obtained via ClassUtils.getDefaultClassLoader()
  - 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
  - getBeanFactory
```
protected BeanFactory getBeanFactory()
```
    Return the BeanFactory that this bean runs in.
  - getBeanTypeConverter
```
protected TypeConverter 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.
    
    See Also:
    
    ConfigurableBeanFactory.getTypeConverter(), SimpleTypeConverter
  - afterPropertiesSet
```
public void afterPropertiesSet()
                        throws java.lang.Exception
```
    Eagerly create the singleton instance, if necessary.
    
    Specified by:
    
    afterPropertiesSet in interface InitializingBean
    
    Throws:
    
    java.lang.Exception - in the event of misconfiguration (such as failure to set an essential property) or if initialization fails.
  - getObject
```
public final T getObject()
                  throws java.lang.Exception
```
    Expose the singleton instance or create a new prototype instance.
    
    Specified by:
    
    getObject in interface FactoryBean<T>
    
    Returns:
    
    an instance of the bean (can be null)
    
    Throws:
    
    java.lang.Exception - in case of creation errors
    
    See Also:
    
    createInstance(), getEarlySingletonInterfaces()
  - getEarlySingletonInstance
```
private T getEarlySingletonInstance()
                             throws java.lang.Exception
```
    Determine an 'eager singleton' instance, exposed in case of a circular reference. Not called in a non-circular scenario.
    
    Throws:
    
    java.lang.Exception
  - getSingletonInstance
```
private T getSingletonInstance()
                        throws java.lang.IllegalStateException
```
    Expose the singleton instance (for access through the 'early singleton' proxy).
    
    Returns:
    
    the singleton instance that this FactoryBean holds
    
    Throws:
    
    java.lang.IllegalStateException - if the singleton instance is not initialized
  - destroy
```
public void destroy()
             throws java.lang.Exception
```
    Destroy the singleton instance, if any.
    
    Specified by:
    
    destroy in interface DisposableBean
    
    Throws:
    
    java.lang.Exception - in case of shutdown errors. Exceptions will get logged but not rethrown to allow other beans to release their resources too.
    
    See Also:
    
    destroyInstance(Object)
  - getObjectType
```
public abstract java.lang.Class<?> getObjectType()
```
    This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.
    
    Specified by:
    
    getObjectType in interface FactoryBean<T>
    
    Returns:
    
    the type of object that this FactoryBean creates, or null if not known at the time of the call
    
    See Also:
    
    FactoryBean.getObjectType()
  - createInstance
```
protected abstract T createInstance()
                             throws java.lang.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:
    
    java.lang.Exception - if an exception occured during object creation
    
    See Also:
    
    getObject()
  - getEarlySingletonInterfaces
```
protected java.lang.Class<?>[] 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 else. 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:
    
    FactoryBeanNotInitializedException
  - destroyInstance
```
protected void destroyInstance(T instance)
                        throws java.lang.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:
    
    java.lang.Exception - in case of shutdown errors
    
    See Also:
    
    createInstance()

Class AbstractFactoryBean<T>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

logger

singleton

beanClassLoader

beanFactory

initialized

singletonInstance

earlySingletonInstance

Constructor Detail

AbstractFactoryBean

Method Detail

setSingleton

isSingleton

setBeanClassLoader

setBeanFactory

getBeanFactory

getBeanTypeConverter

afterPropertiesSet

getObject

getEarlySingletonInstance

getSingletonInstance

destroy

getObjectType

createInstance

getEarlySingletonInterfaces

destroyInstance