The Spring Framework

Class DelegatingActionProxy

  extended by org.apache.struts.action.Action
      extended by org.springframework.web.struts.DelegatingActionProxy

public class DelegatingActionProxy
extends Action

Proxy for a Spring-managed Struts Action that is defined in ContextLoaderPlugIn's WebApplicationContext.

The proxy is defined in the Struts config file, specifying this class as the action class. This class will delegate to a Struts Action bean in the ContextLoaderPlugIn context.

<action path="/login" type="org.springframework.web.struts.DelegatingActionProxy"/>
The name of the Action bean in the WebApplicationContext will be determined from the mapping path and module prefix. This can be customized by overriding the determineActionBeanName method.


A corresponding bean definition in the ContextLoaderPlugin context would look as follows; notice that the Action is now able to leverage fully Spring's configuration facilities:

 <bean name="/login" class="myapp.MyAction">
   <property name="...">...</property>
Note that you can use a single ContextLoaderPlugIn for all Struts modules. That context can in turn be loaded from multiple XML files, for example split according to Struts modules. Alternatively, define one ContextLoaderPlugIn per Struts module, specifying appropriate "contextConfigLocation" parameters. In both cases, the Spring bean name has to include the module prefix.

If you want to avoid having to specify DelegatingActionProxy as the Action type in your struts-config file (for example to be able to generate your Struts config file with XDoclet) consider using the DelegatingRequestProcessor. The latter's disadvantage is that it might conflict with the need for a different RequestProcessor subclass.

The default implementation delegates to the DelegatingActionUtils class as much as possible, to reuse as much code as possible with DelegatingRequestProcessor and DelegatingTilesRequestProcessor.

Note: The idea of delegating to Spring-managed Struts Actions originated in Don Brown's Spring Struts Plugin. ContextLoaderPlugIn and DelegatingActionProxy constitute a clean-room implementation of the same idea, essentially superseding the original plugin. Many thanks to Don Brown and Matt Raible for the original work and for the agreement to reimplement the idea in Spring proper!

Juergen Hoeller
See Also:
determineActionBeanName(org.apache.struts.action.ActionMapping), DelegatingRequestProcessor, DelegatingTilesRequestProcessor, DelegatingActionUtils, ContextLoaderPlugIn

Field Summary
Fields inherited from class org.apache.struts.action.Action
defaultLocale, servlet
Constructor Summary
Method Summary
protected  String determineActionBeanName(ActionMapping mapping)
          Determine the name of the Action bean, to be looked up in the WebApplicationContext.
 ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response)
          Pass the execute call on to the Spring-managed delegate Action.
protected  Action getDelegateAction(ActionMapping mapping)
          Return the delegate Action for the given mapping.
protected  WebApplicationContext getWebApplicationContext(ActionServlet actionServlet, ModuleConfig moduleConfig)
          Fetch ContextLoaderPlugIn's WebApplicationContext from the ServletContext, falling back to the root WebApplicationContext.
Methods inherited from class org.apache.struts.action.Action
addErrors, addMessages, execute, generateToken, getDataSource, getDataSource, getErrors, getLocale, getMessages, getResources, getResources, getServlet, isCancelled, isTokenValid, isTokenValid, resetToken, saveErrors, saveErrors, saveErrors, saveMessages, saveMessages, saveToken, setLocale, setServlet
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public DelegatingActionProxy()
Method Detail


public ActionForward execute(ActionMapping mapping,
                             ActionForm form,
                             HttpServletRequest request,
                             HttpServletResponse response)
                      throws Exception
Pass the execute call on to the Spring-managed delegate Action.

execute in class Action
See Also:


protected Action getDelegateAction(ActionMapping mapping)
                            throws BeansException
Return the delegate Action for the given mapping.

The default implementation determines a bean name from the given ActionMapping and looks up the corresponding bean in the WebApplicationContext.

mapping - the Struts ActionMapping
the delegate Action
BeansException - if thrown by WebApplicationContext methods
See Also:


protected WebApplicationContext getWebApplicationContext(ActionServlet actionServlet,
                                                         ModuleConfig moduleConfig)
                                                  throws IllegalStateException
Fetch ContextLoaderPlugIn's WebApplicationContext from the ServletContext, falling back to the root WebApplicationContext.

This context is supposed to contain the Struts Action beans to delegate to.

actionServlet - the associated ActionServlet
moduleConfig - the associated ModuleConfig
the WebApplicationContext
IllegalStateException - if no WebApplicationContext could be found
See Also:
DelegatingActionUtils.findRequiredWebApplicationContext(org.apache.struts.action.ActionServlet, org.apache.struts.config.ModuleConfig), ContextLoaderPlugIn.SERVLET_CONTEXT_PREFIX


protected String determineActionBeanName(ActionMapping mapping)
Determine the name of the Action bean, to be looked up in the WebApplicationContext.

The default implementation takes the mapping path and prepends the module prefix, if any.

mapping - the Struts ActionMapping
the name of the Action bean
See Also:
DelegatingActionUtils.determineActionBeanName(org.apache.struts.action.ActionMapping), ActionConfig.getPath(), ModuleConfig.getPrefix()

The Spring Framework

Copyright © 2002-2007 The Spring Framework.