public class PropertyPathFactoryBean extends Object implements FactoryBean<Object>, BeanNameAware, BeanFactoryAware
FactoryBean
that evaluates a property path on a given target object.
The target object can be specified directly or via a bean name.
Usage examples:
<!-- target bean to be referenced by name --> <bean id="tb" class="org.springframework.beans.TestBean" singleton="false"> <property name="age" value="10"/> <property name="spouse"> <bean class="org.springframework.beans.TestBean"> <property name="age" value="11"/> </bean> </property> </bean> <!-- will result in 12, which is the value of property 'age' of the inner bean --> <bean id="propertyPath1" class="org.springframework.beans.factory.config.PropertyPathFactoryBean"> <property name="targetObject"> <bean class="org.springframework.beans.TestBean"> <property name="age" value="12"/> </bean> </property> <property name="propertyPath" value="age"/> </bean> <!-- will result in 11, which is the value of property 'spouse.age' of bean 'tb' --> <bean id="propertyPath2" class="org.springframework.beans.factory.config.PropertyPathFactoryBean"> <property name="targetBeanName" value="tb"/> <property name="propertyPath" value="spouse.age"/> </bean> <!-- will result in 10, which is the value of property 'age' of bean 'tb' --> <bean id="tb.age" class="org.springframework.beans.factory.config.PropertyPathFactoryBean"/>
If you are using Spring 2.0 and XML Schema support in your configuration file(s), you can also use the following style of configuration for property path access. (See also the appendix entitled 'XML Schema-based configuration' in the Spring reference manual for more examples.)
<!-- will result in 10, which is the value of property 'age' of bean 'tb' --> <util:property-path id="name" path="testBean.age"/>Thanks to Matthias Ernst for the suggestion and initial prototype!
setTargetObject(java.lang.Object)
,
setTargetBeanName(java.lang.String)
,
setPropertyPath(java.lang.String)
OBJECT_TYPE_ATTRIBUTE
Constructor and Description |
---|
PropertyPathFactoryBean() |
Modifier and Type | Method and Description |
---|---|
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. |
boolean |
isSingleton()
While this FactoryBean will often be used for singleton targets,
the invoked getters for the property path might return a new object
for each call, so we have to assume that we're not returning the
same object for each
getObject() call. |
void |
setBeanFactory(BeanFactory beanFactory)
Callback that supplies the owning factory to a bean instance.
|
void |
setBeanName(String beanName)
The bean name of this PropertyPathFactoryBean will be interpreted
as "beanName.property" pattern, if neither "targetObject" nor
"targetBeanName" nor "propertyPath" have been specified.
|
void |
setPropertyPath(String propertyPath)
Specify the property path to apply to the target.
|
void |
setResultType(Class<?> resultType)
Specify the type of the result from evaluating the property path.
|
void |
setTargetBeanName(String targetBeanName)
Specify the name of a target bean to apply the property path to.
|
void |
setTargetObject(Object targetObject)
Specify a target object to apply the property path to.
|
public void setTargetObject(Object targetObject)
targetObject
- a target object, for example a bean reference
or an inner beansetTargetBeanName(java.lang.String)
public void setTargetBeanName(String targetBeanName)
targetBeanName
- the bean name to be looked up in the
containing bean factory (e.g. "testBean")setTargetObject(java.lang.Object)
public void setPropertyPath(String propertyPath)
propertyPath
- the property path, potentially nested
(e.g. "age" or "spouse.age")public void setResultType(Class<?> resultType)
Note: This is not necessary for directly specified target objects or singleton target beans, where the type can be determined through introspection. Just specify this in case of a prototype target, provided that you need matching by type (for example, for autowiring).
resultType
- the result type, for example "java.lang.Integer"public void setBeanName(String beanName)
setBeanName
in interface BeanNameAware
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 setBeanFactory(BeanFactory beanFactory)
BeanFactoryAware
Invoked after the population of normal bean properties
but before an initialization callback such as
InitializingBean.afterPropertiesSet()
or a custom init-method.
setBeanFactory
in interface BeanFactoryAware
beanFactory
- owning BeanFactory (never null
).
The bean can immediately call methods on the factory.BeanInitializationException
@Nullable public Object getObject() throws BeansException
FactoryBean
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 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
)BeansException
FactoryBeanNotInitializedException
public Class<?> getObjectType()
FactoryBean
null
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()
getObject()
call.isSingleton
in interface FactoryBean<Object>
FactoryBean.getObject()
,
SmartFactoryBean.isPrototype()