Re: [Springframework-developer] Auto-wiring by type - too many instances when proxying?

[<jue...@we...>]

Hi Mike,

That's indeed a fairly typical scenario. I've considered this =
repeatedly, but haven't come to any conclusion yet. "Hiding" certain =
beans in a generic fashion is not as simple as it might seem: After all, =
at least the transactional proxy needs to reference its target, so the =
target can't be completely hidden.

When autowiring bean properties, you could use AUTOWIRE_BY_NAME as =
alternative - matching a "spaceManager" property to a "spaceManager" =
bean. However, with constructors, autowiring constructor arguments by =
type remains the only option.

Note that when auto-proxying targets, for example with =
BeanNameAutoProxyCreator, there's just one visible bean: The target =
automatically gets wrapped with a proxy. However, this is just =
appropriate for transaction demarcation if all your targets stick to the =
same method naming pattern; else, all those different transaction =
attributes in a single TransactionAttributeSource will get messy.

Juergen


-----Original Message-----
From: spr...@li...
[mailto:spr...@li...]On Behalf
Of Mike Cannon-Brookes
Sent: Wednesday, April 28, 2004 4:43 PM
To: <spr...@li...>
<spr...@li...>
Subject: [Springframework-developer] Auto-wiring by type - too many
instances when proxying?


Hey guys,

Just wondering how you get around this scenario.

We were playing around with autowiring today, specifically using the=20
ListableBeanFactory.autowire(Class,=20
AutowiringBeanFactory.AUTOWIRE_CONSTRUCTOR, false) method.

Now the problem is that if I have two beans of effectively the same=20
type (say SpaceManager) - the autowiring no longer works.

The reason we have two beans implementing SpaceManager interface is=20
that there's an implementation defined with all it's properties=20
('spaceManagerTarget') and then a transaction proxy factory bean=20
wrapping the impl with transaction attributes ('spaceManager'). I think=20
this is a fairly standard type of scenario.

However both are exposing the SpaceManager interface, hence the auto=20
wiring fails.

What to do? Has anyone else faced this problem?

I never access the 'spaceManagerTarget' from within my application, is=20
it possible to 'hide' this instance somehow?

Cheers,
Mike

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