Hi..
Hmmm.. I do not see why (in the code you came across) one should both
populate a form with the properties of the DTO + set the DTO as an attribute
on the request object?
It should be enough to populate the form with properties from the DTO.
I have seen other solutions where Views (JSPs) always contains a Form tag
(eg. form bean). When you populate the form bean from the action you do
something like this.
pseudo code, action:
// Form bean representing the view
myFormBean.setVO(myVO);
pseudo code, form
private MyVOClass myVO;
private void populate()
{
// Call methods to populate form
}
// Setter that get called from action
void setVO(MyVOClass myVO)
{
this.myVO = myVO;
populate();
}
The VO could also contain selections for listboxes, comboboxes, etc. So that
the VO is View (form) specific, and the DTO (the object/data you really want
to store) can be extracted from the VO.
You can say that with this approach you have two objects
DTO:
The object that "travels" across tiers and is persisted, maybe as entity
beans or whatever.
VO:
The view specific object that holds the DTO and what else is needed for
generating the view.
So the DTO is a subset of the VO.
I think is is a nice way to do things, but it introduces yet another object
representing the same data.
On the other hand it clean separates what data is needed for the generating
the view (VO) and what data is needed to be persisted or transferred to
antoher tier (DTO).
My few cents
Regards
Henrik
----- Original Message -----
From: "M. Onur Tokan" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, September 22, 2004 5:05 PM
Subject: Transfer Data Objects between Actions and Views
> Hi,
>
> I come across the following code. It uses
> "request.setAttribute("employee",employeeDTO);" for transfering
> employeeDTO. Is it the only practice for doing this?
>
> --
> Regards,
> M. Onur Tokan
>
> <code>
> package net.reumann;
>
> import org.apache.struts.action.Action;
> import org.apache.struts.action.ActionForward;
> import org.apache.struts.action.ActionMapping;
> import org.apache.struts.action.ActionForm;
> import org.apache.commons.beanutils.BeanUtils;
> import javax.servlet.http.HttpServletRequest;
> import javax.servlet.http.HttpServletResponse;
>
> public final class InsertEmployeeAction extends Action {
>
> public ActionForward execute(ActionMapping mapping,
> ActionForm form,
> HttpServletRequest request,
> HttpServletResponse response)
> throws Exception {
> EmployeeService service = new EmployeeService();
> EmployeeForm employeeForm = (EmployeeForm) form;
> EmployeeDTO employeeDTO = new EmployeeDTO();
> BeanUtils.copyProperties( employeeDTO, employeeForm );
> service.insertEmployee( employeeDTO );
> request.setAttribute("employee",employeeDTO);
> return (mapping.findForward("success"));
> }
> }
> </code>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
