Business logic flaw in pet store?

Question

I am not sure if I understood correctly. In the requestmappings.xml file, we have a section like:
<url-mapping url="/validatenewaccount" screen="ACCOUNT_CREATED" useRequestHandler="true" useFlowHandler="true">
<request-handler-class>com.sun.j2ee.blueprints.petstore.control.web.handlers.AccountHandler</request-handler-class>
<flow-handler class="com.sun.j2ee.blueprints.petstore.control.web.handlers.AccountFlowHandler">
<handler-result result="1" screen="ACCOUNT_CREATED"/>
<handler-result result="2" screen="ACCOUNT_CREATED"/>
<handler-result result="3" screen="MISSING_FORM_DATA"/>
</flow-handler>
</url-mapping>
One question is both handler classes are executed BEFORE the web page displayed. But generally we need to perform some actions AFTER the page load but before going to next page. There is no logic to perfrom this kind of action in the pet store design.
One example, suppose we are adding a customer. We have two pages -- customer_add displays some input fields, customer_view display the customer info after the adding. We have the following steps:
1) Display the customer_add page;
2) When user fills the form and click submit, we must do the input validation BEFORE saving the info to db. So we use a FlowHandler class to validate the user input. If fails, we need redisplay customer_add page;
But if validation successful, we must save the info to db BEFORE displaying customer_view page. But we cannot do it here, as the RequestProcessor (supposed to do sth against db through EJB) must be executed BEFORE the page load and BEFORE the FlowHandler.
Someone may argue why don't we save the into to db at the beginning of displaying customer_view page. Remember, the customer_view page is nothing related to the customer_add page. The customer_view page could be called from somewhere else, such as search customers, view customers, edit customers.
The customer adding logic should really follow the customer_add page.
I am not sure if it is a design flaw or I just understand wrong.
Thanks,

Answer 1

Hmm, seems like you did not understood correctly.
The validation of data posted by the user form should be done in the AccountHandler class (in your example, that means in a RequestHandler class), not in the AccountFlowHandler. If the data is not valid, throw an exception or set some value in the session, than the flow handler will use the value to decide what page to display ( back to the input page or success page, etc).
If the data is valid, the AccountHandler generates an event that goes to the EJB layer and updates the DB.
Regards,
Cristian