RE: [Springframework-developer] bean factory scope question

[James C. <jim...@do...>]

Is there a way to define a bean property that is "optional"? If it =
exists,
wire it up, otherwise let it remain null? This can be useful when =
creating
Spring-enabled components.=20

For example, I may have an email bean wired to a user management bean.

<bean id=3D"usermgmt" class=3D"my.UserManagement">
	<property name=3D"emailService">
		<ref bean=3D"usermgmt.emailService" />
	</property>
</bean>

If the user provided a bean with a name of "usermgmt.emailService" my =
class
would use this service to send emails. If the bean was not provided, I =
would
skip sending emails or maybe use a default implementation.

Perhaps an optional attribute would help?
	<property name=3D"emailService" optional=3D"true">

I think this will become a bigger deal as people start componentizing =
there
spring modules.

One way to solve this now is provide the bean name instead of a bean
reference to the UserManagement bean. Then this bean is responsible for
looking up the bean reference and handling it accordingly whether it =
exists
or not. This is more in the style of JNDI lookups and not very IoC, plus =
it
makes my beans more spring aware than I would like.

> -----Original Message-----
> Beans that are supposed to be available for references by name indeed =
need
> to be defined at the root level. Inner beans are always anonymous and
> usually don't carry a name. Defining a name for them only adds value =
if
> they
> are aware of their own name (BeanNameAware).