Package org.apache.struts.extras.actions

Class MappingDispatchAction

java.lang.Object
org.apache.struts.action.Action
org.apache.struts.extras.actions.BaseAction
org.apache.struts.extras.actions.DispatchAction
org.apache.struts.extras.actions.MappingDispatchAction
All Implemented Interfaces:
Serializable
public class MappingDispatchAction extends DispatchAction

An abstract Action that dispatches to a public method that is named by the parameter attribute of the corresponding ActionMapping. This is useful for developers who prefer to combine many related actions into a single Action class.

To configure the use of this action in your struts-config.xml file, create an entry like this:


   <action path="/saveSubscription"
           type="org.example.SubscriptionAction"
           name="subscriptionForm"
          scope="request"
          input="/subscription.jsp"
      parameter="method"/>

where 'method' is the name of a method in your subclass of MappingDispatchAction that has the same signature (other than method name) of the standard Action.execute method. For example, you might combine the methods for managing a subscription into a single MappingDispatchAction class using the following methods:

  • public ActionForward create(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
  • public ActionForward edit(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
  • public ActionForward save(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
  • public ActionForward delete(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
  • public ActionForward list(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception

for which you would create corresponding <action> configurations that reference this class:


  <action path="/createSubscription"
          type="org.example.SubscriptionAction"
          parameter="create">
      <forward name="success" path="/editSubscription.jsp"/>
  </action>

  <action path="/editSubscription"
          type="org.example.SubscriptionAction"
          parameter="edit">
      <forward name="success" path="/editSubscription.jsp"/>
  </action>

  <action path="/saveSubscription"
          type="org.example.SubscriptionAction"
          parameter="save"
          name="subscriptionForm"
          validate="true"
          input="/editSubscription.jsp"
          scope="request">
      <forward name="success" path="/savedSubscription.jsp"/>
  </action>

  <action path="/deleteSubscription"
          type="org.example.SubscriptionAction"
          name="subscriptionForm"
          scope="request"
          input="/subscription.jsp"
          parameter="delete">
      <forward name="success" path="/deletedSubscription.jsp"/>
  </action>

  <action path="/listSubscriptions"
          type="org.example.SubscriptionAction"
          parameter="list">
      <forward name="success" path="/subscriptionList.jsp"/>
  </action>

NOTE - Unlike DispatchAction, mapping characteristics may differ between the various handlers, so you can combine actions in the same class that, for example, differ in their use of forms or validation. Also, a request parameter, which would be visible to the application user, is not required to enable selection of the handler method.

Since:
Struts 1.2
Version:
$Rev$ $Date$
See Also:

  • Constructor Details

    • MappingDispatchAction

      public MappingDispatchAction()

  • Method Details

    • execute

      public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
      Process the specified HTTP request, and create the corresponding HTTP response (or forward to another web component that will create it). Return an ActionForward instance describing where and how control should be forwarded, or null if the response has already been completed. This method dispatches the request to other methods of MappingDispatchAction using the 'parameter' attribute of ActionMapping and Java Introspection.
      Overrides:
      execute in class DispatchAction
      Parameters:
      mapping - The ActionMapping used to select this instance
      form - The optional ActionForm bean for this request (if any)
      request - The HTTP request we are processing
      response - The HTTP response we are creating
      Returns:
      Return an ActionForward instance describing where and how control should be forwarded, or null if the response has already been completed.
      Throws:
      Exception - if an exception occurs

    • unspecified

      protected ActionForward unspecified(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
      Method which is dispatched to when there is no value for the parameter in the ActionMapping. Subclasses of MappingDispatchAction should override this method if they wish to provide default behavior different than throwing a ServletException.
      Overrides:
      unspecified in class DispatchAction
      Parameters:
      mapping - The ActionMapping used to select this instance
      form - The optional ActionForm bean for this request (if any)
      request - The HTTP request we are processing
      response - The HTTP response we are creating
      Returns:
      Return an ActionForward instance describing where and how control should be forwarded, or null if the response has already been completed.
      Throws:
      Exception - if an exception occurs

    • getParameter

      protected String getParameter(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception

      Returns the parameter value.

      Overrides:
      getParameter in class DispatchAction
      Parameters:
      mapping - The ActionMapping used to select this instance
      form - The optional ActionForm bean for this request (if any)
      request - The HTTP request we are processing
      response - The HTTP response we are creating
      Returns:
      The ActionMapping parameter's value
      Throws:
      Exception - if the parameter is missing.

    • getMethodName

      protected String getMethodName(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response, String parameter) throws Exception
      Returns the method name, given a parameter's value.
      Overrides:
      getMethodName in class DispatchAction
      Parameters:
      mapping - The ActionMapping used to select this instance
      form - The optional ActionForm bean for this request (if any)
      request - The HTTP request we are processing
      response - The HTTP response we are creating
      parameter - The ActionMapping parameter's name
      Returns:
      The method's name.
      Throws:
      Exception - if an error occurs
      Since:
      Struts 1.2.0