hrm. you say you will have a serialization problem if you lookup the bean
directly and hold on to it. but isnt that exactly what you want? to pull out
a prototype bean and keep it inside the form's scope? the form is in
httpsession and so the bean will be serialized. so if that is what you want
to do you have to make sure the bean is serializable and do the lookup
yourself.
we can probably add @SpringBean(transient=false) or something like that to
keep the reference instead of discarding it, but that wont solve your
serialization problem, it will just save you doing the lookup yourself.
so what exactly do you want?
-igor
On 6/3/07, Rüdiger Schulz <[EMAIL PROTECTED]> wrote:
I put a breakpoint in the constructor of my Form, which has the
@SpringBean annotation on ia property named logic.
Before the super() call, logic is null.
After that, it is set to $Proxy39, with a h-attribute to a
org.apache.wicket.proxy.LazyInitProxyFactory$JdkHandler. The target
property of the handler is null.
After the next line, where I call a method from logic, the target
property is set to the bean instance.
So it seems that the reference gets lost in the first call.
But, as you said that the bean is transient anyway, I think that
prototype beans could not be used that way for holding state of wicket
components, because that state should certainly also be kept when
using the back button.
I'm not sure what is best then. I could get a reference to the spring
bean directly from ApplicationContext, and just keep it. But then I
would face the problem of serialization.
The best thing would be IMHO if the proxy could somehow do an
automatic re-lookup from Spring for prototype beans, so that not a new
instance is fetched from the container, but the same as before. But I
don't know enough about Spring to say if that is even possible.
2007/6/3, Eelco Hillenius <[EMAIL PROTECTED]>:
> I'm not that familiar with the code, but the interesting thing is that
> LazyInitProxyFactory$JdkHandler does cache the bean it located:
>
> if (target == null)
> {
> target = locator.locateProxyTarget();
> }
> return proxy.invoke(target, args);
>
> The target is a transient member of JdkHandler and judging from the
> code, once the bean is located it should just be reused until the page
> is serialized/ deserialized (for backbutton support or when
> clustered).
>
> Can you use you debugger to find out what exactly happens?
>
> Eelco
>
> On 6/1/07, Rüdiger Schulz <[EMAIL PROTECTED]> wrote:
> > Right, forgot the Stacktraces:
> >
> > The first when calling super():
> > at KitManagementBean.<init>(KitManagementBean.java:34)
> > at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
> > at sun.reflect.NativeConstructorAccessorImpl.newInstance(
NativeConstructorAccessorImpl.java:39)
> > at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(
DelegatingConstructorAccessorImpl.java:27)
> > at java.lang.reflect.Constructor.newInstance(Constructor.java
:513)
> > at org.springframework.beans.BeanUtils.instantiateClass(
BeanUtils.java:85)
> > at
org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate
(SimpleInstantiationStrategy.java:61)
> > at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean
(AbstractAutowireCapableBeanFactory.java:732)
> > at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance
(AbstractAutowireCapableBeanFactory.java:720)
> > at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean
(AbstractAutowireCapableBeanFactory.java:386)
> > at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(
AbstractBeanFactory.java:270)
> > at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(
AbstractBeanFactory.java:164)
> > at
org.springframework.context.support.AbstractApplicationContext.getBean(
AbstractApplicationContext.java:707)
> > at org.apache.wicket.spring.SpringBeanLocator.lookupSpringBean
(SpringBeanLocator.java:240)
> > at
org.apache.wicket.spring.SpringBeanLocator.locateProxyTarget(
SpringBeanLocator.java:163)
> > at
org.apache.wicket.spring.injection.annot.AnnotProxyFieldValueFactory.testLocator
(AnnotProxyFieldValueFactory.java:124)
> > at
org.apache.wicket.spring.injection.annot.AnnotProxyFieldValueFactory.getFieldValue
(AnnotProxyFieldValueFactory.java:99)
> > at org.apache.wicket.injection.Injector.inject(Injector.java
:109)
> > at org.apache.wicket.injection.ConfigurableInjector.inject(
ConfigurableInjector.java:40)
> > at
org.apache.wicket.injection.ComponentInjector.onInstantiation(
ComponentInjector.java:54)
> > at
org.apache.wicket.Application.notifyComponentInstantiationListeners(
Application.java:916)
> > at org.apache.wicket.Component.<init>(Component.java:708)
> > at org.apache.wicket.MarkupContainer.<init>(
MarkupContainer.java:111)
> > at org.apache.wicket.markup.html.WebMarkupContainer.<init>(
WebMarkupContainer.java:39)
> > at org.apache.wicket.markup.html.form.Form.<init>(Form.java
:233)
> > at KitForm.<init>(KitForm.java:50)
> > at KitEditPage.<init>(KitEditPage.java:45)
> >
> > And from the next line, where I call a method on the bean:
> >
> > at KitManagementBean.<init>(KitManagementBean.java:34)
> > at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
> > at sun.reflect.NativeConstructorAccessorImpl.newInstance(
NativeConstructorAccessorImpl.java:39)
> > at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(
DelegatingConstructorAccessorImpl.java:27)
> > at java.lang.reflect.Constructor.newInstance(Constructor.java
:513)
> > at org.springframework.beans.BeanUtils.instantiateClass(
BeanUtils.java:85)
> > at
org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate
(SimpleInstantiationStrategy.java:61)
> > at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean
(AbstractAutowireCapableBeanFactory.java:732)
> > at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance
(AbstractAutowireCapableBeanFactory.java:720)
> > at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean
(AbstractAutowireCapableBeanFactory.java:386)
> > at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(
AbstractBeanFactory.java:270)
> > at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(
AbstractBeanFactory.java:164)
> > at
org.springframework.context.support.AbstractApplicationContext.getBean(
AbstractApplicationContext.java:707)
> > at org.apache.wicket.spring.SpringBeanLocator.lookupSpringBean
(SpringBeanLocator.java:240)
> > at
org.apache.wicket.spring.SpringBeanLocator.locateProxyTarget(
SpringBeanLocator.java:163)
> > at
org.apache.wicket.proxy.LazyInitProxyFactory$JdkHandler.invoke(
LazyInitProxyFactory.java:389)
> > at org.apache.wicket.proxy.$Proxy39.init(Unknown Source)
> > at KitForm.<init>(KitForm.java:51)
> > at KitEditPage.<init>(KitEditPage.java:45)
> >
> >
> > 2007/6/1, Rüdiger Schulz <[EMAIL PROTECTED]>:
> > > Hello everybody,
> > >
> > > I already tried to chat on ##wicket about this, but it's probably
too
> > > complex for IRC...
> > >
> > > I'm using Wicket 1.3.0 snapshot and Spring 2.0 on JDK6 / Jetty. For
a
> > > more complex form I wanted to use a "stateful" Springbean, to which
I
> > > applied scope="prototype". The idea is to have one bean instance for
> > > every Form instance. I would access the bean with PropertyModels and
> > > direct method calls during construction (i.e. setting initial state
> > > from input parameters) and during events, which would alter the
state.
> > > I inject the bean into the Form with @SpringBean annotation.
> > >
> > > This works somehow, but sometimes, especially after using the
> > > backbutton, I had the problem that the internal state was reset. So
I
> > > analyzed the stack in the constructor of the bean implementation,
and
> > > found out that it was called twice during construction of the Form.
> > > First, during the super() call, and then again in the next line
during
> > > a method call on that bean. I appended both stacktraces below. The
> > > proxy itself does not change.
> > >
> > > This happens again after going back and e.g. submitting again. This
> > > results in a NPE, because the internal state is reset.
> > >
> > > I understand from reading the mailing list that the Wicket-Proxy
does
> > > nothing but a lookup in the Application context, and does not know
or
> > > care about spring scope.
> > >
> > > And here I'm a little stuck. I am already considering to put the
state
> > > into the Form, and make the Bean a singleton without any internal
> > > state. As that would mean some heavy refactoring, I would prefer a
way
> > > where the Spring acces would work as I want. Or is this a wrong way
> > > altogether?
> > >
> > > thanks in advance for any comments.
> > >
> > > --
> > > greetings from Berlin,
> > >
> > > Rüdiger Schulz
> > >
> > > www.2rue.de
> > >
> >
> >
> > --
> > greetings from Berlin,
> >
> > Rüdiger Schulz
> >
> > www.2rue.de
> >
> >
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--
greetings from Berlin,
Rüdiger Schulz
www.2rue.de
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