public class FieldRetrievingFactoryBean extends Object implements FactoryBean<Object>, BeanNameAware, BeanClassLoaderAware, InitializingBean
FactoryBean which 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.
<util:constant static-field="java.sql.Connection.TRANSACTION_SERIALIZABLE"/>
setStaticField(java.lang.String)OBJECT_TYPE_ATTRIBUTE| Constructor and Description |
|---|
FieldRetrievingFactoryBean() |
| Modifier and Type | Method and Description |
|---|---|
void |
afterPropertiesSet()
Invoked by the containing
BeanFactory after it has set all bean properties
and satisfied BeanFactoryAware, ApplicationContextAware etc. |
Object |
getObject()
Return an instance (possibly shared or independent) of the object
managed by this factory.
|
Class<?> |
getObjectType()
Return the type of object that this FactoryBean creates,
or
null if not known in advance. |
Class<?> |
getTargetClass()
Return the target class on which the field is defined.
|
String |
getTargetField()
Return the name of the field to be retrieved.
|
Object |
getTargetObject()
Return the target object on which the field is defined.
|
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(ClassLoader classLoader)
Callback that supplies the bean
class loader to
a bean instance. |
void |
setBeanName(String beanName)
The bean name of this FieldRetrievingFactoryBean will be interpreted
as "staticField" pattern, if neither "targetClass" nor "targetObject"
nor "targetField" have been specified.
|
void |
setStaticField(String staticField)
Set a fully qualified static field name to retrieve,
e.g.
|
void |
setTargetClass(Class<?> targetClass)
Set the target class on which the field is defined.
|
void |
setTargetField(String targetField)
Set the name of the field to be retrieved.
|
void |
setTargetObject(Object targetObject)
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)
setBeanName in interface BeanNameAwarebeanName - 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)
BeanClassLoaderAwareclass 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.
setBeanClassLoader in interface BeanClassLoaderAwareclassLoader - the owning class loaderpublic void afterPropertiesSet()
throws ClassNotFoundException,
NoSuchFieldException
InitializingBeanBeanFactory after it has set all bean properties
and satisfied BeanFactoryAware, ApplicationContextAware etc.
This method allows the bean instance to perform validation of its overall configuration and final initialization when all bean properties have been set.
afterPropertiesSet in interface InitializingBeanClassNotFoundExceptionNoSuchFieldException@Nullable public Object getObject() throws IllegalAccessException
FactoryBeanAs 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.
getObject in interface FactoryBean<Object>null)IllegalAccessExceptionFactoryBeanNotInitializedExceptionpublic Class<?> getObjectType()
FactoryBeannull 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.
getObjectType in interface FactoryBean<Object>null if not known at the time of the callListableBeanFactory.getBeansOfType(java.lang.Class<T>)public boolean isSingleton()
FactoryBeanFactoryBean.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.
isSingleton in interface FactoryBean<Object>FactoryBean.getObject(),
SmartFactoryBean.isPrototype()