org.springframework.web.struts
Class DelegatingActionProxy

java.lang.Object
  org.apache.struts.action.Action
      org.springframework.web.struts.DelegatingActionProxy

public class DelegatingActionProxy

extends org.apache.struts.action.Action

Proxy for a Spring-managed Struts 1.1 Action that's defined in ContextLoaderPlugIn's WebApplicationContext.

The proxy is defined in the Struts config file, specifying this class as action class. It 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.

Example:

• mapping path "/login" -> bean name "/login"
  
• mapping path "/login", module prefix "/mymodule" -> bean name "/mymodule/login"

A corresponding bean definition in the ContextLoaderPlugin context looks as follows, being able to fully leverage Spring's configuration facilities:

 <bean name="/login" class="myapp.MyAction">
   <property name="...">...</property>
 </bean>

If you want to avoid having to specify DelegatingActionProxy as Action type in your struts-config, for example to be able to generate your Struts config file with XDoclet, consider 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 fas 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 standard Spring!

Since:

05.04.2004

Author:

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

ACTION_SERVLET_KEY, APPLICATION_KEY, DATA_SOURCE_KEY, defaultLocale, ERROR_KEY, EXCEPTION_KEY, FORM_BEANS_KEY, FORWARDS_KEY, LOCALE_KEY, MAPPING_KEY, MAPPINGS_KEY, MESSAGE_KEY, MESSAGES_KEY, MULTIPART_KEY, PLUG_INS_KEY, REQUEST_PROCESSOR_KEY, servlet, SERVLET_KEY, TRANSACTION_TOKEN_KEY

Constructor Summary

DelegatingActionProxy()

Method Summary

protected java.lang.String	determineActionBeanName(org.apache.struts.action.ActionMapping mapping) Determine the name of the Action bean, to be looked up in the WebApplicationContext.
org.apache.struts.action.ActionForward	execute(org.apache.struts.action.ActionMapping mapping, org.apache.struts.action.ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Pass the execute call on to the Spring-managed delegate Action.
protected org.apache.struts.action.Action	getDelegateAction(org.apache.struts.action.ActionMapping mapping) Return the delegate Action for the given mapping.
protected WebApplicationContext	getWebApplicationContext() Return the WebApplicationContext that this proxy delegates to.
protected WebApplicationContext	initWebApplicationContext(org.apache.struts.action.ActionServlet actionServlet) Fetch ContextLoaderPlugIn's WebApplicationContext from the ServletContext, containing the Struts Action beans to delegate to.
void	setServlet(org.apache.struts.action.ActionServlet actionServlet) Initialize the WebApplicationContext for this Action.

Methods inherited from class org.apache.struts.action.Action

execute, generateToken, getDataSource, getDataSource, getLocale, getResources, getResources, getResources, getServlet, isCancelled, isTokenValid, isTokenValid, perform, perform, resetToken, saveErrors, saveMessages, saveToken, setLocale, toHex

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DelegatingActionProxy

public DelegatingActionProxy()

Method Detail

setServlet

public void setServlet(org.apache.struts.action.ActionServlet actionServlet)

Initialize the WebApplicationContext for this Action.

See Also:

initWebApplicationContext(org.apache.struts.action.ActionServlet)

initWebApplicationContext

protected WebApplicationContext initWebApplicationContext(org.apache.struts.action.ActionServlet actionServlet)
                                                   throws java.lang.IllegalStateException

Fetch ContextLoaderPlugIn's WebApplicationContext from the ServletContext, containing the Struts Action beans to delegate to.

Parameters:

actionServlet - the associated ActionServlet

Returns:

the WebApplicationContext

Throws:

java.lang.IllegalStateException - if no WebApplicationContext could be found

See Also:

DelegatingActionUtils.initWebApplicationContext(org.apache.struts.action.ActionServlet), ContextLoaderPlugIn.SERVLET_CONTEXT_ATTRIBUTE

getWebApplicationContext

protected final WebApplicationContext getWebApplicationContext()

Return the WebApplicationContext that this proxy delegates to.

execute

public org.apache.struts.action.ActionForward execute(org.apache.struts.action.ActionMapping mapping,
                                                      org.apache.struts.action.ActionForm form,
                                                      javax.servlet.http.HttpServletRequest request,
                                                      javax.servlet.http.HttpServletResponse response)
                                               throws java.lang.Exception

Pass the execute call on to the Spring-managed delegate Action.

Throws:

java.lang.Exception

See Also:

getDelegateAction(org.apache.struts.action.ActionMapping)

getDelegateAction

protected org.apache.struts.action.Action getDelegateAction(org.apache.struts.action.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.

Parameters:

mapping - the Struts ActionMapping

Returns:

the delegate Action

Throws:

BeansException - if thrown by WebApplicationContext methods

See Also:

determineActionBeanName(org.apache.struts.action.ActionMapping)

determineActionBeanName

protected java.lang.String determineActionBeanName(org.apache.struts.action.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.

Parameters:

mapping - the Struts ActionMapping

Returns:

the name of the Action bean

See Also:

DelegatingActionUtils.determineActionBeanName(org.apache.struts.action.ActionMapping), ActionConfig.getPath(), ModuleConfig.getPrefix()