Class ObjectFactoryCreatingFactoryBean
- All Implemented Interfaces:
Aware,BeanClassLoaderAware,BeanFactoryAware,DisposableBean,FactoryBean<ObjectFactory<Object>>,InitializingBean
FactoryBean implementation that
returns a value which is an ObjectFactory
that in turn returns a bean sourced from a BeanFactory.
As such, this may be used to avoid having a client object directly calling
BeanFactory.getBean(String) to get
a (typically prototype) bean from a
BeanFactory, which would be a
violation of the inversion of control principle. Instead, with the use
of this class, the client object can be fed an
ObjectFactory instance as a
property which directly returns only the one target bean (again, which is
typically a prototype bean).
A sample config in an XML-based
BeanFactory might look as follows:
<beans>
<!-- Prototype bean since we have state -->
<bean id="myService" class="a.b.c.MyService" scope="prototype"/>
<bean id="myServiceFactory"
class="org.springframework.beans.factory.config.ObjectFactoryCreatingFactoryBean">
<property name="targetBeanName"><idref local="myService"/></property>
</bean>
<bean id="clientBean" class="a.b.c.MyClientBean">
<property name="myServiceFactory" ref="myServiceFactory"/>
</bean>
</beans>
The attendant MyClientBean class implementation might look
something like this:
package a.b.c;
import org.springframework.beans.factory.ObjectFactory;
public class MyClientBean {
private ObjectFactory<MyService> myServiceFactory;
public void setMyServiceFactory(ObjectFactory<MyService> myServiceFactory) {
this.myServiceFactory = myServiceFactory;
}
public void someBusinessMethod() {
// get a 'fresh', brand new MyService instance
MyService service = this.myServiceFactory.getObject();
// use the service object to effect the business logic...
}
}
An alternate approach to this application of an object creational pattern
would be to use the ServiceLocatorFactoryBean
to source (prototype) beans. The ServiceLocatorFactoryBean approach
has the advantage of the fact that one doesn't have to depend on any
Spring-specific interface such as ObjectFactory,
but has the disadvantage of requiring runtime class generation. Please do
consult the ServiceLocatorFactoryBean JavaDoc
for a fuller discussion of this issue.
- Since:
- 1.0.2
- Author:
- Colin Sampaleanu, Juergen Hoeller
- See Also:
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Field Summary
Fields inherited from class org.springframework.beans.factory.config.AbstractFactoryBean
loggerFields inherited from interface org.springframework.beans.factory.FactoryBean
OBJECT_TYPE_ATTRIBUTE -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoidEagerly create the singleton instance, if necessary.protected ObjectFactory<Object>Template method that subclasses must override to construct the object returned by this factory.Class<?>This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.voidsetTargetBeanName(String targetBeanName) Set the name of the target bean.Methods inherited from class org.springframework.beans.factory.config.AbstractFactoryBean
destroy, destroyInstance, getBeanFactory, getBeanTypeConverter, getEarlySingletonInterfaces, getObject, isSingleton, setBeanClassLoader, setBeanFactory, setSingleton
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Constructor Details
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ObjectFactoryCreatingFactoryBean
public ObjectFactoryCreatingFactoryBean()
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Method Details
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setTargetBeanName
Set the name of the target bean.The target does not have to be a non-singleton bean, but realistically always will be (because if the target bean were a singleton, then said singleton bean could simply be injected straight into the dependent object, thus obviating the need for the extra level of indirection afforded by this factory approach).
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afterPropertiesSet
Description copied from class:AbstractFactoryBeanEagerly create the singleton instance, if necessary.- Specified by:
afterPropertiesSetin interfaceInitializingBean- Overrides:
afterPropertiesSetin classAbstractFactoryBean<ObjectFactory<Object>>- Throws:
Exception- in the event of misconfiguration (such as failure to set an essential property) or if initialization fails for any other reason
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getObjectType
Description copied from class:AbstractFactoryBeanThis abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.- Specified by:
getObjectTypein interfaceFactoryBean<ObjectFactory<Object>>- Specified by:
getObjectTypein classAbstractFactoryBean<ObjectFactory<Object>>- Returns:
- the type of object that this FactoryBean creates,
or
nullif not known at the time of the call - See Also:
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createInstance
Description copied from class:AbstractFactoryBeanTemplate 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
AbstractFactoryBean.getObject()call.- Specified by:
createInstancein classAbstractFactoryBean<ObjectFactory<Object>>- Returns:
- the object returned by this factory
- See Also:
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