Re: [Springframework-developer] Singelton FactoryBeans are asked for an object before beanFactor.getBean(name) is called by application

[Colin S. <col...@ex...>]

This is happening because AbstractApplicationContext foreces singletons 
(which includes your FactoryBean) to be pre-instantiated. This 
essentially calls getBean() on the bean, which ends up calling getObject().

Coincidentally, just a few days ago I asked here why singletons were 
always preinstantiated, with no ability to turn off this behaviour, but 
nobody commented... It probably makes sense to be able to turn this off 
for specific beans.

Regards,
Colin

Cameron Braid wrote:

> I have a FactoryBean that is a singleton.  It is a prototype factory 
> (is that correct terminoligy?)
>
> When the application context initialized, the FactoryBean.getObject() 
> is being called before I call getBean() from my application.
>
> The problem is that the contract for BeanFactory.getObject() states 
> that it shoud never be null.
>
>     /**
>      * Return an instance (possibly shared or independent) of the object
>      * managed by this factory. As with a BeanFactory, this allows
>      * support for both the Singleton and Prototype design pattern.
>      * @return an instance of the bean *(should never be null)*
>      * @throws Exception in case of creation errors
>      */
>     Object getObject() throws Exception;
>
> Though in my application, I can't gaurantee this.  I am relying on 
> source of information that doesn't exist until a servlet call is made.
>
> How come this happens, and is it necessary to create an instance that 
> gets thrown away ?
>
> Cheers
>
> Cameron