[Springframework-developer] Rationale for setApplicationContext() coming after afterPropertiesSet()

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

I've had a couple of discussions now with people where I've tried to=20
explain why setApplicationContext comes after afterPropertiesSet (and=20
after any custom initializing method you define), and frankly, I think=20
it just doesn't make sense except for the fact that it's that way right n=
ow.

Most beans should of course not be using the application context, but if=20
they need it, people are not going to understand the rationale as to why=20
that property is set after the initializing method is called, and that=20
they must instead treat setApplicationContext itself as an initializer=20
method.

I don't know if anybody thinks it's worth changing the order, but if=20
not, this thing is going to hit new users on the head on a regular=20
basis... At a minimum, if no code is changed, we need to update the=20
JavaDoc for ApplicationContextAware to explain the order. I can do that..=
.

Regards,
Colin

j=C3=BCrgen h=C3=B6ller [werk3AT] wrote:

>Actually, this is intended behavior, although it may be debatable whethe=
r it is appropriate. setApplicationContext is not really meant to be comb=
ined with an init-method. The latter is for non-Spring-aware beans, while=
 the former is the strongest dependency a bean can have on Spring. You sh=
ould *not* design your beans to depend on that initialization order.
>
>As a solution, you could put your initialization code in your setApplica=
tionContext implementation, or in an initApplicationContext() method that=
 gets triggered by setApplicationContext. Have a look at the ApplicationO=
bjectSupport convenience base class, it provides such a method out of the=
 box. Of course, extending ApplicationObjectSupport is not an option if y=
ou already have a different natural base class.
>
>Juergen
>
>
>-----Original Message-----
>From: Keith Donald [mailto:kd...@cs...]
>Sent: Thursday, October 30, 2003 4:22 PM
>To: spr...@li...
>Subject: RE: [Springframework-user] setApplicationContext not being
>called
>
>
>Juergen,
>
>Wanted to update you on this issue post M2.  setApplicationContext is be=
ing called now on all my ApplicationContextAware beans, thanks.  The only=
 issue I have remaining is it seems the bean init-method method ("initial=
ize()" in my case) is called by the container before setApplicationContex=
t.  My initialize() method does stuff that requires the context - for exa=
mple, it looks up messages for initializing view components.  So I would =
really need setApplicationContext() called before initialize() to prevent=
 NullPointerExceptions.
>
>Thanks,
>Keith
>
>2003-10-30 10:16:58,099 DEBUG [com.csi.cogids.console.QueryNavigator] - =
<initialize called>
>2003-10-30 10:16:58,193 DEBUG [com.csi.cogids.console.qQueryNavigator] -=
 <setApplicationContext called>
>
>Keith Donald
>Senior Software Engineer
>kd...@cs...
>321-676-2923 x403
>
>
>
>
>-----Original Message-----
>From: spr...@li... [mailto:springfra=
mew...@li...] On Behalf Of j=C3=BCrgen h=C3=B6=
ller [werk3AT]
>Sent: Thursday, October 23, 2003 2:14 AM
>To: spr...@li...
>Subject: Re: [Springframework-user] setApplicationContext not being call=
ed
>
>
>Keith,
>=20
>This was caused by the fact that ApplicationContextAware was being proce=
ssed after the underlying bean factory finished its work, on demand in ge=
tBean calls to the application context. I've completely reworked this for=
 1.0 M2; now, the bean factory has a BeanPostProcessor hook that is also =
internally used for processing ApplicationContextAware beans, to be appli=
ed when the underlying bean factory creates any kind of bean.
>=20
>So as of 1.0 M2, to be released tomorrow, this should work properly in a=
ll cases. If there should be any remaining issues, please report them aga=
inst 1.0 M2. If you're eager, you can also try a CVS snapshot today.
>=20
>Juergen
>=20
>=20
>
>	-----Urspr=C3=BCngliche Nachricht-----=20
>	Von: Keith Donald [mailto:kd...@cs...]=20
>	Gesendet: Di 21.10.2003 19:50=20
>	An: spr...@li...=20
>	Cc:=20
>	Betreff: [Springframework-user] setApplicationContext not being called
>=09
>=09
>
>	Forgive me if this issue has already been addressd.  It appears
>	setApplicationContext(ApplicationContext) is not being called on my
>	ApplicationContextAware prototype beans that are not directly instantia=
ted
>	by a call to beanFactory.getBean(beanName), but rather are wired "child=
"
>	beans instantiated as a result of a <bean ref> references from a parent
>	prototype.
>=09
>	To give you an example of what I mean:
>=09
>	        // parent prototype
>	        <bean      id=3D"sessionVisualizerPage"
>	                class=3D"com.csi.cogids.console.SessionVisualizerPage"
>	            singleton=3D"false">
>	          <property name=3D"queryNavigator"><ref
>	bean=3D"queryNavigator"/></property>
>	     </bean>
>=09
>	        // child prototype
>	    <bean       id=3D"queryNavigator"
>	             class=3D"com.csi.cogids.console.query.QueryNavigator"
>	         singleton=3D"false"
>	       init-method=3D"initialize">
>	      <property name=3D"newQueryAction"><ref
>	bean=3D"newQueryAction"/></property>
>	      <property name=3D"newGroupAction"><ref
>	bean=3D"newGroupAction"/></property>
>	    </bean>
>=09
>	A sessionVisualizerPage prototype gets instantiated when the page is lo=
aded
>	in my application.  The queryNavigator prototype also gets instantiated
>	because of the <bean ref>.  setApplicationContext() IS called on
>	sessionVisualizerPage, but not on QueryNavigator, even though both are
>	ApplicationContextAware for message lookups.
>=09
>	Thanks,
>	Keith
>=09
>	Keith Donald
>	Senior Software Engineer
>	kd...@cs...
>	321-676-2923 x403
>=09
>