Apple WebObjects 3.5 - Manual (Page 52)

Chapter 3 Common Methods
52
Invoking an Action
The second phase of the request-response loop involves
invokeActionForRequest:inContext: . WebObjects forwards this method from object to
object until it is handled by the dynamic element associated with the user action
(typically, a submit button, a hyperlink, and active image, or a form).
Use invokeActionForRequest:inContext: if you want to return a page other than the one
requested. This scenario might occur if the user requests a page that has a
dependency on another page that the user must fill out first. The user might, for
example, finish ordering items from a catalog application and want to go to a
fulfillment page but first have to supply credit card information.
The following example, implemented in Session.wos , returns a “CreditCard” page
if the user hasn’t supplied this information yet:
// WebScript example
- invokeActionForRequest:request inContext:context {
id creditPage;
id responsePage = [super invokeActionForRequest:request
inContext:context];
id nameOfNextPage = [responsePage name];
if ([self verified]==NO &&
[nameOfNextPage isEqual:@"Fulfillment"]) {
creditPage = [[self application]
pageWithName:@"CreditCard"];
[creditPage setNameOfNextPage:nameOfNextPage];
return creditPage;
}
return responsePage;
}
//Java example
public Element invokeActionForRequest(Request request, Context contenxt)
{
Component creditPage;
Component responsePage = super.invokeActionForRequest(request,
context);
String nameOfNextPage = responsePage.name();
if (verified()==false &&
(nameOfNextPage.compareTo("Fulfillment") == 0) {
creditPage = application().pageWithName("CreditCard");
creditPage.setNameOfNextPage(nameOfNextPage);
return creditPage;
}
return responsePage;
}
When the application receives a request for a new page (say, a fulfillment page),
the session object determines whether or not the user has supplied valid credit-
card data by checking the value of its
verified variable. If the value of verified is NO,
the session object returns the “CreditCard” component. As shown in the