Spring FactoryBean and scopes working together
I'd like to use FactoryBeans and scopes together. Specifically, I'd like the object created and returned by a FactoryBean to be placed into a specified (perhaps custom) scope. The issue is that doing the following:
<bean class="x.y.z.TestFactoryBean" scope="test" />
Results in the FactoryBean itself being scoped, and has somewhat unpredictable behaviour on the object created by the factory. I understand why this is; the factory itself is a first-class spring-managed bean, and has its own lifecycle. However, I can't find a way to specify that the object returned from the factory should itself be scoped.
On the other hand, this does exactly what I want (as long as TestFactoryBean does NOT implement the FactoryBean interface):
<bean class="x.y.z.TestFactoryBean" name="testFactory">
<bean class="x.y.z.TestBean" factory-bean="testFactory"
factory-method="getObject" scope="test" />
So the real question is, how can I make Spring behave like it does for the 2nd example above, but using real Factor开发者_JAVA百科yBeans?
You can't easily use a custom scope on a bean returned from a FactoryBean
.
From Spring's Java documentation:
FactoryBeans can support singletons and prototypes
If you want the FactoryBean
's returned bean to have the prototype scope, then you must implement the isSingleton()
method like this:
public class TestFactoryBean implements FactoryBean<TestBean> {
// the rest of the required methods are removed for simplicity reasons..
public boolean isSingleton() {
return false;
}
}
To support a custom scope, you have to implement the logic yourself and it will not be very intuitive, since the FactoryBean
only provides the isSingleton()
method. I will rather recommend using another solution than FactoryBean
for beans with custom scope.
Hope this helps!
I solved the same issue using custom holder bean.
Factory bean:
@Component
@Configurable()
public class EventBusFactory implements FactoryBean<EventBus> {
@Override
public EventBus getObject() throws Exception {
return new SimpleEventBus();
}
@Override
public Class<?> getObjectType() {
return EventBus.class;
}
@Override
public boolean isSingleton() {
return false;
}
}
Bean holder:
@Configurable
@Component
@Scope("session")
public class EventBusHolder {
@Autowired
private EventBus eventBus;
public EventBus getEventBus() {
return eventBus;
}
public void setEventBus(EventBus eventBus) {
this.eventBus = eventBus;
}
}
And then I use holder instead of the required entity.
@Component
@Configurable
@Scope("session")
public class UicPlaceController extends PlaceController {
@Autowired
public UicPlaceController(EventBusHolder eventBus) {
super(eventBus.getEventBus());
}
...
}
The solution looks a little bit ugly, but still, it solves the issue.
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