Navigation Annotations

Strecks uses annotations to implement pluggable navigation and view rendering in the action bean. Two navigation-related annotations are currently supported.

@NavigateForward is used to handle various mechanisms for ActionForward-based navigation.
@SpringView enables Spring MVC's view rendering mechanisms, particularly useful for localized views and accessing alternative view rendering technologies.

@NavigateForward

The BasicAction interface shown below is coupled with navigation, because the result returned from execute() is used to locate an ActionForward using ActionMapping.findForward(String). @NavigateForward provides a mechanism for decoupling request processing execution methods from navigation. An example is shown below:

@Controller(name = NavigableController.class)
public class ExampleNavigableAction implements NavigableAction
{
	public void execute()
	{
	 	 //omitted
	}

	@NavigateForward
	public String getResult()
	{
		return "success";
	}
}

This allows different styles of navigation to be used without changing the request processing interface. @NavigateForward supports three styles of navigation by default. In each case, the supported style depends on the return value of the method annotated using @NavigateForward.

String	Functionally identical to the `BasicController`'s behaviour: the returned `String` is used to find an `ActionForward` using `ActionMapping.findForward(String)`
ActionForward	The `ActionForward` returned is wrapped using an `ActionForwardViewAdapter` and propagated to the Struts navigation handler.
Page	The `Page` bean is a Java representation of a JSP, used to control access to the page's data as well as implement formatting logic on behalf of the page. In this case, `@NavigateForward` will return a `PageForward` instance. `PageForward` extends `ActionForward` and wraps the `Page` instance.
ViewAdapter	The @NavigateForward can return a `ViewAdapter`. This will simply be propagated by the action controller.

Summary

Location	Method returning navigation information
Purpose	Identify the controller implementation
Usage	In action beans which use `NavigableControllerAction` controllers

@SpringView

The @SpringView annotation is used to enable Spring MVC based view rendering. Spring MVC supports a number of different view rendering mechanisms, including JSP with JSTL, Tiles, XSLT, Excel, PDF and Jasper Reports. Spring Views can either be created programmatically, accessed from the Spring ApplicationContext or accessed via a Spring ViewResolver. More details on each of these mechanisms as well as examples are found in the Spring Integration section.

Summary

Location	Method returning navigation information. This method must return a Spring `ModelAndView` instance.
Purpose	Enable view rendering using Spring's `View.render()` method.
Usage	In action beans which use `NavigableControllerAction` controllers.