org.apache.struts.actions
Class LookupDispatchAction

java.lang.Object
  org.apache.struts.action.Action
      org.apache.struts.actions.BaseAction
          org.apache.struts.actions.DispatchAction
              org.apache.struts.actions.LookupDispatchAction

public abstract class LookupDispatchAction
extends DispatchAction

An abstract Action that dispatches to the subclass mapped execute method. This is useful in cases where an HTML form has multiple submit buttons with the same name. The button name is specified by the parameter property of the corresponding ActionMapping. To configure the use of this action in your struts-config.xml file, create an entry like this:

   <action path="/test"
           type="org.example.MyAction"
           name="MyForm"
          scope="request"
          input="/test.jsp"
      parameter="method"/>
 

which will use the value of the request parameter named "method" to locate the corresponding key in ApplicationResources. For example, you might have the following ApplicationResources.properties:

    button.add=Add Record
    button.delete=Delete Record
  

And your JSP would have the following format for submit buttons:

   <html:form action="/test">
    <html:submit property="method">
      <bean:message key="button.add"/>
    </html:submit>
    <html:submit property="method">
      <bean:message key="button.delete"/>
    </html:submit>
  </html:form>
  

Your subclass must implement both getKeyMethodMap and the methods defined in the map. An example of such implementations are:

  protected Map getKeyMethodMap() {
      Map map = new HashMap();
      map.put("button.add", "add");
      map.put("button.delete", "delete");
      return map;
  }

  public ActionForward add(ActionMapping mapping,
          ActionForm form,
          HttpServletRequest request,
          HttpServletResponse response)
          throws IOException, ServletException {
      // do add
      return mapping.findForward("success");
  }

  public ActionForward delete(ActionMapping mapping,
          ActionForm form,
          HttpServletRequest request,
          HttpServletResponse response)
          throws IOException, ServletException {
      // do delete
      return mapping.findForward("success");
  }
 

Notes - If duplicate values exist for the keys returned by getKeys, only the first one found will be returned. If no corresponding key is found then an exception will be thrown. You can override the method unspecified to provide a custom handler. If the submit was cancelled (a html:cancel button was pressed), the custom handler cancelled will be used instead.

Field Summary

protected Map	keyMethodMap Resource key to method name lookup.
protected Map	localeMap Reverse lookup map from resource value to resource key.

Fields inherited from class org.apache.struts.actions.DispatchAction

clazz, log, methods, types

Fields inherited from class org.apache.struts.actions.BaseAction

messages

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

servlet

Constructor Summary

LookupDispatchAction()

Method Summary

ActionForward	execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) Process the specified HTTP request, and create the corresponding HTTP response (or forward to another web component that will create it).
protected abstract Map	getKeyMethodMap() Provides the mapping from resource key to method name.
protected String	getLookupMapName(HttpServletRequest request, String keyName, ActionMapping mapping) Lookup the method name corresponding to the client request's locale.
protected String	getMethodName(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response, String parameter) Returns the method name, given a parameter's value.

Methods inherited from class org.apache.struts.actions.DispatchAction

cancelled, dispatchMethod, getMethod, getParameter, unspecified

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

addErrors, addMessages, execute, generateToken, getErrors, getLocale, getMessages, getResources, getResources, getServlet, isCancelled, isTokenValid, isTokenValid, resetToken, 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

Field Detail

localeMap

protected Map localeMap

Reverse lookup map from resource value to resource key.

keyMethodMap

protected Map keyMethodMap

Resource key to method name lookup.

Constructor Detail

LookupDispatchAction

public LookupDispatchAction()

Method Detail

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.

Overrides:

execute in class DispatchAction

Parameters:

mapping - The ActionMapping used to select this instance

request - The HTTP request we are processing

response - The HTTP response we are creating

form - The optional ActionForm bean for this request (if any)

Returns:

Describes where and how control should be forwarded.

Throws:

Exception - if an error occurs

getKeyMethodMap

protected abstract Map getKeyMethodMap()

Provides the mapping from resource key to method name.

Returns:

Resource key / method name map.

getLookupMapName

protected String getLookupMapName(HttpServletRequest request,
                                  String keyName,
                                  ActionMapping mapping)
                           throws ServletException

Lookup the method name corresponding to the client request's locale.

Parameters:

request - The HTTP request we are processing

keyName - The parameter name to use as the properties key

mapping - The ActionMapping used to select this instance

Returns:

The method's localized name.

Throws:

ServletException - if keyName cannot be resolved

Since:

Struts 1.2.0

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