How would I specify a bean reference as an argument-resolver, in Spring 3-1? - spring

Question

This is a syntax question about a Spring configuration (refer to spring-beans-3.1.xsd and spring-mvc-3.1.xsd).
I have a specific bean definition (id="SecurityRequestParametersArgumentResolver") that I want to register as a custom argument resolver. The xml fragment is:
<bean id="SecurityRequestParametersArgumentResolver"
class="xxx.security.web.SecurityRequestParametersArgumentResolver">
<property name="credentialsManager" ref="CredentialsManager" />
<property name="tokenService" ref="TokenService" />
</bean>
... AND I would like to use a bean reference. The following three lines don't obey the xsd-grammar ( what should be the correct tag declaration here? )
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean ref="SecurityRequestParametersArgumentResolver"/>
</mvc:argument-resolvers>
</mvc:annotation-driven>
... All of the examples I have seen look like THIS, and thus are going after the default no-argument constructor
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean class="class="xxx.security.web.SecurityRequestParametersArgumentResolver"/>
</mvc:argument-resolvers>
</mvc:annotation-driven>
Repeating the question, what should the Spring syntax be in order to use a bean reference as a custom argument resolver?
Thanks!

Answer 1

At least the constructor argument problem can be solved easily
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean class="class="xxx.security.web.SecurityRequestParametersArgumentResolver">
<constructor-arg value="123"/>
</bean>
</mvc:argument-resolvers>
</mvc:annotation-driven>
But I do not know any way to use a reference instead of a bean within <mvc:argument-resolvers>. But depending on what you want to do, there are several workarrounds.
Use a Bean Factory
Create a proxy class that implements the HandlerMethodArgumentResolver and forward every call to an other instance, then you can have your own SecurityRequestParametersArgumentResolver like a normal bean and register the Proxy in the <mvc:argument-resolvers> section.
Proxy:
class HandlerMethodArgumentResolverProxy
implements HandlerMethodArgumentResolver{
HandlerMethodArgumentResolver delegate;
publicHandlerMethodArgumentResolverProxy
(HandlerMethodArgumentResolver delegate){
this.delegate=delegate;
}
public boolean supportsParameter(MethodParameter parameter) {
this.delegate.supportsParameter(parameter);
}
//delegate for resolveArgument
}
config:
<bean id="securityRequestParametersArgumentResolver"
class="xxx.security.web.SecurityRequestParametersArgumentResolver">
...
</bean>
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean class "HandlerMethodArgumentResolverProxy">
<constructor-arg
ref="securityRequestParametersArgumentResolver"/>
</bean>
</mvc:argument-resolvers>
</mvc:annotation-driven>