Add mvc namespace element for registering Parameterizable View Controllers [SPR-6413]

[spring-projects-issues]

Keith Donald opened SPR-6413 and commented

Spring Roo has the requirement to map a web requests to static views. Rather than configure a "default handler" that attempts to map any request not handled by a Controller to a view, they're now defining a ParameterizableViewController bean for each static view [which is a safer and more explicit]. This change results in some extra low-level bean configuration that could be simplified.

Currently, the following must be added to mvc-config.xml:

<!-- Required to enable invocation of org.springframework.web.servlet.Controllers -->
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter" />
<!-- Required for bean name-based request mapping -->
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping" p:order ="1">
    <!-- Register any interceptors, typically duplicating interceptor set with other handler mappings -->
    <property name="interceptors"> ... </property>
</bean>
<!-- Required for each static view controller -->
<bean name="/index" class="org.springframework.web.servlet.mvc.ParameterizableViewController" p:viewName="index" />

Proposal:

• We can simplify the above config by encapsulating the registration of the SimpleControllerHandlerAdapter and BeanNameUrlHandlerMapping beans in the mvc:annotation-driven element.
• We can simplify the registration of ParameterizableViewControllers by introducing a custom mvc namespace tag such as:

<mvc:view-controller path="/index" /> <!-- defaults to view name "index" via RequestToViewNameTranslator -->

<mvc:view-controller path="/foo" view-name="aCustomViewName" />

---

Affects: 3.0 RC2

Issue Links:

• ROO-385 Use new Spring MVC namespace ("is depended on by")

Referenced from: commits de1d548

[spring-projects-issues]

Keith Donald commented

When you have custom handler interceptors registered using the mvc:interceptors sub element of the mvc:annotation-driven element, you'd have to also duplicate registration of those interceptors for the BeanNameUrlHandlerMapping as well. This is not ideal - the mvc:annotation-driven element should really encapsulate the registration of both handler mappings and the setup of the interceptor set for each.