org.apache.struts.actions

Class 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 MapkeyMethodMap
Resource key to method name lookup.
protected MaplocaleMap
Reverse lookup map from resource value to resource key.
static LogLOG
Commons Logging instance.
Method Summary
ActionForwardexecute(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 MapgetKeyMethodMap()
Provides the mapping from resource key to method name.
protected StringgetLookupMapName(HttpServletRequest request, String keyName, ActionMapping mapping)
Lookup the method name corresponding to the client request's locale.
protected StringgetMethodName(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response, String parameter)
Returns the method name, given a parameter's value.
MapinitLookupMap(HttpServletRequest request, Locale userLocale)
This is the first time this Locale is used so build the reverse lookup Map.

Field Detail

keyMethodMap

protected Map keyMethodMap
Resource key to method name lookup.

localeMap

protected Map localeMap
Reverse lookup map from resource value to resource key.

LOG

private static final Log LOG
Commons Logging instance.

Method Detail

execute

public 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). Return an ActionForward instance describing where and how control should be forwarded, or null if the response has already been completed.

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)
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)
Returns the method name, given a parameter's value.

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.

Since: Struts 1.2.0

initLookupMap

private Map initLookupMap(HttpServletRequest request, Locale userLocale)
This is the first time this Locale is used so build the reverse lookup Map. Search for message keys in all configured MessageResources for the current module.
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