org.apache.struts.chain.legacy: public class: DispatchAction

org.apache.struts.chain.legacy
public class: DispatchAction [javadoc | source]

java.lang.Object
   org.apache.struts.action.Action
      org.apache.struts.chain.legacy.DispatchAction

An Action implementation that delegates to a Chain (or Command) that is specified by a request parameter whose name is configured in the parameter attribute of the <action> element configuring this action. For example:

  <action path="/myaction"
          type="org.apache.struts.chain.legacy.DispatchAction"
          name="myform"
         scope="request"
         input="/mypage.jsp"
     parameter="name-of-request-parameter"

Prior to calling the specified chain (or command), this action sets up a Context object containing the relevant properties, along with the following additional attributes:

mapping - The ActionMapping passed to our execute() method
form - The ActionForm passed to our execute() method

After execution of the specified command or chain is completed, the following context attributes are examined (in this order) to determine how to proceed.

exception - If a java.lang.Exception is found here, it will be rethrown as the outcome of this action.
forward - If an org.apache.struts.action.ActionForward is found here, it will be returned as the outcome of this action. Otherwise, null will be returned.

Method from org.apache.struts.chain.legacy.DispatchAction Summary:
execute, getCatalog

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.apache.struts.chain.legacy.DispatchAction Detail:
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { // Set up a context for this request Context context = new ServletWebContext (getServlet().getServletContext(), request, response); context.put("mapping", mapping); context.put("form", form); // Delegate to the specified command String name = mapping.getParameter(); Command command = getCatalog().getCommand(request.getParameter(name)); command.execute(context); // Ignore return state // Return results as appropriate Exception exception = null; try { exception = (Exception) context.get("exception"); if (exception != null) { throw exception; } } catch (ClassCastException e) { ; // It is not an Exception } ActionForward forward = null; try { forward = (ActionForward) context.get("forward"); } catch (ClassCastException e) { forward = null; // It is not an ActionForward } return forward; } Delegate to the command chain specified in our configuration.
protected Catalog getCatalog() { if (catalog == null) { catalog = CatalogFactory.getInstance().getCatalog(); } return catalog; } Return the `Catalog` we will use to acquire the `Command` to be executed. NOTE: Any race condition calling this method is harmless, so do not bother to synchronize.

Method from org.apache.struts.chain.legacy.DispatchAction Detail:

 public ActionForward execute(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception {
        // Set up a context for this request
        Context context = new ServletWebContext
            (getServlet().getServletContext(), request, response);
        context.put("mapping", mapping);
        context.put("form", form);
        // Delegate to the specified command
        String name = mapping.getParameter();
        Command command = getCatalog().getCommand(request.getParameter(name));
        command.execute(context); // Ignore return state
        // Return results as appropriate
        Exception exception = null;
        try {
            exception = (Exception) context.get("exception");
            if (exception != null) {
                throw exception;
            }
        } catch (ClassCastException e) {
            ; // It is not an Exception
        }
        ActionForward forward = null;
        try {
            forward = (ActionForward) context.get("forward");
        } catch (ClassCastException e) {
            forward = null; // It is not an ActionForward
        }
        return forward;
}

Delegate to the command chain specified in our configuration.

 protected Catalog getCatalog() {
        if (catalog == null) {
            catalog = CatalogFactory.getInstance().getCatalog();
        }
        return catalog;
}

Return the Catalog we will use to acquire the Command to be executed. NOTE: Any race condition calling this method is harmless, so do not bother to synchronize.