package org.g4studio.core.mvc.xstruts.actions;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.g4studio.core.mvc.xstruts.Globals;
import org.g4studio.core.mvc.xstruts.action.ActionForm;
import org.g4studio.core.mvc.xstruts.action.ActionForward;
import org.g4studio.core.mvc.xstruts.action.ActionMapping;
import org.g4studio.core.mvc.xstruts.config.MessageResourcesConfig;
import org.g4studio.core.mvc.xstruts.config.ModuleConfig;
import org.g4studio.core.mvc.xstruts.util.MessageResources;
/**
* <p>
* An abstract <strong>Action</strong> that dispatches to the subclass mapped
* <code>execute</code> 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 <code>parameter</code> property of the corresponding ActionMapping. To
* configure the use of this action in your <code>struts-config.xml</code> file,
* create an entry like this:
* </p>
*
* <pre>
* <action path="/test"
* type="org.example.MyAction"
* name="MyForm"
* scope="request"
* input="/test.jsp"
* parameter="method"/>
* </pre>
* <p>
*
* 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:
* </p>
*
* <pre>
* button.add=Add Record
* button.delete=Delete Record
* </pre>
* <p>
*
* And your JSP would have the following format for submit buttons:
* </p>
*
* <pre>
* <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>
* </pre>
* <p>
*
* Your subclass must implement both getKeyMethodMap and the methods defined in
* the map. An example of such implementations are:
* </p>
*
* <pre>
* 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");
* }
* </pre>
* <p>
* <strong>Notes</strong> - 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
* <code>unspecified</code> to provide a custom handler. If the submit was
* cancelled (a <code>html:cancel</code> button was pressed), the custom handler
* <code>cancelled</code> 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 <code>ActionForward</code> instance describing where and how
* control should be forwarded, or <code>null</code> 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.
* @throws 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.
*
* @param request
* The HTTP request we are processing
* @param userLocale
* The locale for this request
* @return The reverse lookup map for the specified locale.
*/
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 <code>ActionMapping</code> parameter's name
* @return The method's name.
* @throws Exception
* if an error occurs
* @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;
}
}