* 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.
*
*/
public abstract class LookupDispatchAction extends DispatchAction {
/**
* Commons Logging instance.
*/
private static final Log LOG = LogFactory.getLog(LookupDispatchAction.class);
/**
* Reverse lookup map from resource value to resource key.
*/
protected Map localeMap = new HashMap();
/**
* Resource key to method name lookup.
*/
protected Map keyMethodMap = null;
// ---------------------------------------------------------- Public Methods
/**
* 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.
*
* @param mapping The ActionMapping used to select this instance
* @param request The HTTP request we are processing
* @param response The HTTP response we are creating
* @param form The optional ActionForm bean for this request (if any)
* @return Describes where and how control should be forwarded.
* @exception Exception if an error occurs
*/
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception {
return super.execute(mapping, form, request, response);
}
/**
* 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.
*/
private Map initLookupMap(HttpServletRequest request, Locale userLocale) {
Map lookupMap = new HashMap();
this.keyMethodMap = this.getKeyMethodMap();
ModuleConfig moduleConfig =
(ModuleConfig) request.getAttribute(Globals.MODULE_KEY);
MessageResourcesConfig[] mrc = moduleConfig.findMessageResourcesConfigs();
// Look through all module's MessageResources
for (int i = 0; i < mrc.length; i++) {
MessageResources resources = this.getResources(request, mrc[i].getKey());
// Look for key in MessageResources
Iterator iter = this.keyMethodMap.keySet().iterator();
while (iter.hasNext()) {
String key = (String) iter.next();
String text = resources.getMessage(userLocale, key);
// Found key and haven't added to Map yet, so add the text
if ((text != null) && !lookupMap.containsKey(text)) {
lookupMap.put(text, key);
}
}
}
return lookupMap;
}
/**
* Provides the mapping from resource key to method name.
*
* @return Resource key / method name map.
*/
protected abstract Map getKeyMethodMap();
/**
* Lookup the method name corresponding to the client request's locale.
*
* @param request The HTTP request we are processing
* @param keyName The parameter name to use as the properties key
* @param mapping The ActionMapping used to select this instance
*
* @return The method's localized name.
* @throws ServletException if keyName cannot be resolved
* @since Struts 1.2.0
*/
protected String getLookupMapName(
HttpServletRequest request,
String keyName,
ActionMapping mapping)
throws ServletException {
// Based on this request's Locale get the lookupMap
Map lookupMap = null;
synchronized(localeMap) {
Locale userLocale = this.getLocale(request);
lookupMap = (Map) this.localeMap.get(userLocale);
if (lookupMap == null) {
lookupMap = this.initLookupMap(request, userLocale);
this.localeMap.put(userLocale, lookupMap);
}
}
// Find the key for the resource
String key = (String) lookupMap.get(keyName);
if (key == null) {
String message =
messages.getMessage("dispatch.resource", mapping.getPath());
LOG.error(message + " '" + keyName + "'");
throw new ServletException(message);
}
// Find the method name
String methodName = (String) keyMethodMap.get(key);
if (methodName == null) {
String message = messages.getMessage(
"dispatch.lookup", mapping.getPath(), key);
throw new ServletException(message);
}
return methodName;
}
/**
* Returns the method name, given a parameter's value.
*
* @param mapping The ActionMapping used to select this instance
* @param form The optional ActionForm bean for this request (if any)
* @param request The HTTP request we are processing
* @param response The HTTP response we are creating
* @param parameter The ActionMapping parameter's name
*
* @return The method's name.
* @since Struts 1.2.0
*/
protected String getMethodName(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response,
String parameter)
throws Exception {
// Identify the method name to be dispatched to.
// dispatchMethod() will call unspecified() if name is null
String keyName = request.getParameter(parameter);
if (keyName == null || keyName.length() == 0) {
return null;
}
String methodName = getLookupMapName(request, keyName, mapping);
return methodName;
}
}