package org.g4studio.core.mvc.xstruts.actions;
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.util.ModuleUtils;
/**
* <p>
* A standard <strong>Action</strong> that switches to a new module and then
* forwards control to a URI (specified in a number of possible ways) within the
* new module.
* </p>
*
* <p>
* Valid request parameters for this Action are:
* </p>
*
* <ul>
*
* <li><strong>page</strong> - Module-relative URI (beginning with "/") to which
* control should be forwarded after switching.</li>
*
* <li><strong>prefix</strong> - The module prefix (beginning with "/") of the
* module to which control should be switched. Use a zero-length string for the
* default module. The appropriate <code>ModuleConfig</code> object will be
* stored as a request attribute, so any subsequent logic will assume the new
* module.</li>
*
* </ul>
*
* @version $Rev: 376812 $ $Date: 2005-05-14 21:27:02 -0400 (Sat, 14 May 2005) $
* @since Struts 1.1
*/
public class SwitchAction extends BaseAction {
// ----------------------------------------------------- Instance Variables
/**
* Commons Logging instance.
*/
protected static Log log = LogFactory.getLog(SwitchAction.class);
/**
* 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 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
* @return 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.
* @throws Exception
* if an exception occurs
*/
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request,
HttpServletResponse response) throws Exception {
// Identify the request parameters controlling our actions
String page = request.getParameter("page");
String prefix = request.getParameter("prefix");
if ((page == null) || (prefix == null)) {
String message = messages.getMessage("switch.required");
log.error(message);
throw new ServletException(message);
}
// Switch to the requested module
ModuleUtils.getInstance().selectModule(prefix, request, getServlet().getServletContext());
if (request.getAttribute(Globals.MODULE_KEY) == null) {
String message = messages.getMessage("switch.prefix", prefix);
log.error(message);
throw new ServletException(message);
}
// Forward control to the specified module-relative URI
return (new ActionForward(page));
}
}