protected ActionForward cancelled(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception 
{
        return null;
}

Method which is dispatched to when the request is a cancel button submit. Subclasses of DispatchAction should override this method if they wish to provide default behavior different than returning null.

 protected ActionForward dispatchMethod(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response,
    String name) throws Exception 
{
        // Make sure we have a valid method name to call.
        // This may be null if the user hacks the query string.
        if (name == null) {
            return this.unspecified(mapping, form, request, response);
        }
        // Identify the method object to be dispatched to
        Method method = null;
        try {
            method = getMethod(name);
        } catch(NoSuchMethodException e) {
            String message =
                    messages.getMessage("dispatch.method", mapping.getPath(), name);
            log.error(message, e);
            String userMsg =
                messages.getMessage("dispatch.method.user", mapping.getPath());
            throw new NoSuchMethodException(userMsg);
        }
        ActionForward forward = null;
        try {
            Object args[] = {mapping, form, request, response};
            forward = (ActionForward) method.invoke(this, args);
        } catch(ClassCastException e) {
            String message =
                    messages.getMessage("dispatch.return", mapping.getPath(), name);
            log.error(message, e);
            throw e;
        } catch(IllegalAccessException e) {
            String message =
                    messages.getMessage("dispatch.error", mapping.getPath(), name);
            log.error(message, e);
            throw e;
        } catch(InvocationTargetException e) {
            // Rethrow the target exception if possible so that the
            // exception handling machinery can deal with it
            Throwable t = e.getTargetException();
            if (t instanceof Exception) {
                throw ((Exception) t);
            } else {
                String message =
                        messages.getMessage("dispatch.error", mapping.getPath(), name);
                log.error(message, e);
                throw new ServletException(t);
            }
        }
        // Return the returned ActionForward instance
        return (forward);
}

Dispatch to the specified method.

 public ActionForward execute(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception 
{
        if (isCancelled(request)) {
            ActionForward af = cancelled(mapping, form, request, response);
            if (af != null) {
                return af;
            }
        }
        // Get the parameter. This could be overridden in subclasses.
        String parameter = getParameter(mapping, form, request, response);
        // Get the method's name. This could be overridden in subclasses.
        String name = getMethodName(mapping, form, request, response, parameter);
	// Prevent recursive calls
	if ("execute".equals(name) || "perform".equals(name)){
		String message =
			messages.getMessage("dispatch.recursive", mapping.getPath());
		log.error(message);
		throw new ServletException(message);
	}
        // Invoke the named method, and return the result
        return dispatchMethod(mapping, form, request, response, name);
}

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.

 protected Method getMethod(String name) throws NoSuchMethodException 
{
        synchronized(methods) {
            Method method = (Method) methods.get(name);
            if (method == null) {
                method = clazz.getMethod(name, types);
                methods.put(name, method);
            }
            return (method);
        }
}

Introspect the current class to identify a method of the specified name that accepts the same parameter types as the execute method does.

 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
        return request.getParameter(parameter);
}

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

 protected String getParameter(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception 
{
        // Identify the request parameter containing the method name
        String parameter = mapping.getParameter();
        if (parameter == null) {
            String message =
                messages.getMessage("dispatch.handler", mapping.getPath());
            log.error(message);
            throw new ServletException(message);
        }
        return parameter;
}

Returns the parameter value.

 protected ActionForward unspecified(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception 
{
        String message =
                messages.getMessage(
                        "dispatch.parameter",
                        mapping.getPath(),
                        mapping.getParameter());
        log.error(message);
        throw new ServletException(message);
}

Method which is dispatched to when there is no value for specified request parameter included in the request. Subclasses of DispatchAction should override this method if they wish to provide default behavior different than throwing a ServletException.