public class FieldRetrievingFactoryBean extends Object implements FactoryBean<Object>, BeanNameAware, BeanClassLoaderAware, InitializingBean
FactoryBeanwhich retrieves a static or non-static field value.
Typically used for retrieving public static final constants. Usage example:
// standard definition for exposing a static field, specifying the "staticField" property <bean id="myField" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean"> <property name="staticField" value="java.sql.Connection.TRANSACTION_SERIALIZABLE"/> </bean> // convenience version that specifies a static field pattern as bean name <bean id="java.sql.Connection.TRANSACTION_SERIALIZABLE" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean"/>
If you are using Spring 2.0, you can also use the following style of configuration for public static fields.
|Constructor and Description|
|Modifier and Type||Method and Description|
Invoked by the containing
Return an instance (possibly shared or independent) of the object managed by this factory.
Return the type of object that this FactoryBean creates, or
Return the target class on which the field is defined.
Return the name of the field to be retrieved.
Return the target object on which the field is defined.
Is the object managed by this factory a singleton? That is, will
Callback that supplies the bean
The bean name of this FieldRetrievingFactoryBean will be interpreted as "staticField" pattern, if neither "targetClass" nor "targetObject" nor "targetField" have been specified.
Set a fully qualified static field name to retrieve, e.g.
Set the target class on which the field is defined.
Set the name of the field to be retrieved.
Set the target object on which the field is defined.
public void setTargetClass(@Nullable Class<?> targetClass)
@Nullable public Class<?> getTargetClass()
public void setTargetObject(@Nullable Object targetObject)
@Nullable public Object getTargetObject()
public void setTargetField(@Nullable String targetField)
@Nullable public String getTargetField()
public void setStaticField(String staticField)
public void setBeanName(String beanName)
beanName- the name of the bean in the factory. Note that this name is the actual bean name used in the factory, which may differ from the originally specified name: in particular for inner bean names, the actual bean name might have been made unique through appending "#..." suffixes. Use the
BeanFactoryUtils.originalBeanName(String)method to extract the original bean name (without suffix), if desired.
public void setBeanClassLoader(ClassLoader classLoader)
class loaderto a bean instance.
Invoked after the population of normal bean properties but
before an initialization callback such as
method or a custom init-method.
classLoader- the owning class loader
public void afterPropertiesSet() throws ClassNotFoundException, NoSuchFieldException
BeanFactoryafter it has set all bean properties and satisfied
This method allows the bean instance to perform validation of its overall configuration and final initialization when all bean properties have been set.
@Nullable public Object getObject() throws IllegalAccessException
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
As of Spring 2.0, FactoryBeans are allowed to return
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.
public Class<?> getObjectType()
nullif 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.
nullif not known at the time of the call
public boolean isSingleton()
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
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
may explicitly indicate independent instances through its
SmartFactoryBean.isPrototype() method. Plain
implementations which do not implement this extended interface are
simply assumed to always return independent instances if the
isSingleton() implementation returns
The default implementation returns
true, since a
FactoryBean typically manages a singleton instance.