org.springframework.beans.factory.FactoryBean implementation that
returns a value which is an org.springframework.beans.factory.ObjectFactory
that in turn returns a bean sourced from a org.springframework.beans.factory.BeanFactory .
As such, this may be used to avoid having a client object directly calling
org. to get
a (typically prototype) bean from a
org., 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
org. 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
org. 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 org.,
but has the disadvantage of requiring runtime class generation. Please do
consult the ServiceLocatorFactoryBean JavaDoc
for a fuller discussion of this issue.
org.springframework.beans.factory.ObjectFactory , ServiceLocatorFactoryBean
| Modifier and Type | Class and Description |
|---|---|
| private static class | ObjectFactoryCreatingFactoryBean.TargetBeanObjectFactory
Independent inner class - for serialization purposes. |
| Modifier and Type | Field and Description |
|---|---|
| private String |
| Access | Constructor and Description |
|---|---|
| public |
| Modifier and Type | Method and Description |
|---|---|
| public void | afterPropertiesSet()
Overrides org. Implements org. |
| protected ObjectFactory | createInstance()
Implements abstract org. |
| public Class | getObjectType()
Implements abstract org. Implements org. |
| public void |
| targetBeanName | back to summary |
|---|---|
| private String targetBeanName
| |
| ObjectFactoryCreatingFactoryBean | back to summary |
|---|---|
| public ObjectFactoryCreatingFactoryBean() | |
| afterPropertiesSet | back to summary |
|---|---|
| public void afterPropertiesSet() throws Exception Overrides org. Implements org. Doc from org. Eagerly create the singleton instance, if necessary.
| |
| createInstance | back to summary |
|---|---|
| protected ObjectFactory Implements abstract org. Doc from org. 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
| |
| getObjectType | back to summary |
|---|---|
| public Class Implements abstract org. Implements org. Doc from org. This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.
| |
| setTargetBeanName | back to summary |
|---|---|
| public void setTargetBeanName(String targetBeanName) 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). | |
| Modifier and Type | Field and Description |
|---|---|
| private final BeanFactory | |
| private final String |
| Access | Constructor and Description |
|---|---|
| public |
| Modifier and Type | Method and Description |
|---|---|
| public Object | getObject()
Implements org. |
| beanFactory | back to summary |
|---|---|
| private final BeanFactory beanFactory | |
| targetBeanName | back to summary |
|---|---|
| private final String targetBeanName | |
| TargetBeanObjectFactory | back to summary |
|---|---|
| public TargetBeanObjectFactory(BeanFactory beanFactory, String targetBeanName) | |
| getObject | back to summary |
|---|---|
| public Object getObject() throws BeansException Implements org. Doc from org. Return an instance (possibly shared or independent) of the object managed by this factory.
| |