Ooops. My bad. I'm still screwing up the terminology and thanks Chuck for the clarification. My point of contention is with the view or view helpers containing the logic which actually interacts with the business layer therefore circumventing the controller. That is, I wanted to make the point that the controller is responsible for interacting with the business layer and subsequentially making the model info (DTOs) accessible to the view.
robert > -----Original Message----- > From: Chuck Cavaness [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, May 15, 2002 2:37 PM > To: Struts Users Mailing List > Subject: RE: Application State == View or Business Logic > > > My thinking is that the data transfer objects (also referred to as value > objects) are still part of the model. The view components do access these > as JavaBeans to help render the dynamic data. Here's a linke from the > Struts user guide: > > http://jakarta.apache.org/struts/userGuide/building_model.html#sys > tem_state > > The business interface can be accessed from the action class, this way > exceptions can be dealt with gracefully and forwarded to the proper > location. The business interface typically returns dto that are placed in > an ActionForm, a DynaForm, or some other shared resource like session > scope. The view components, JSP pages, tags, etc... can use these > immutable > snapshots of the model to render the view for the client. > > That's how I see it working. > > Chuck > > At 03:21 PM 5/15/2002 -0300, you wrote: > >The diagram comes from section 1.4 of the J2EE Blueprints: > Introduction to > >the Blueprints at Sun. > > > >http://java.sun.com/blueprints/guidelines/designing_enterprise_ap plications/introduction/summary/index.html#1035154 > > > > > >Steven Banks > >368-0566 > > > > >>> "Robert Taylor" <[EMAIL PROTECTED]> 05/15/02 02:47PM >>> > >The problem with accessing the model directly from the view is > that if for > >some reason an error were to occur while accessing the model, > then there is > >no mechanism to notify the user with a meaningful message. > > > >For example: > > > >If I had a custom select tag which retrieved a list of companies > where the > >list was retrieved from the database and it was unable to > retrieve the list, > >then there is no intuitive way for the user to know what went > wrong besides > >an empty drop down box. > > > >Where as if your Action (controller) were responsible for retrieving the > >list and placing it in the appropriate scope for the view to > access and an > >error occurred, then the user could be forwarded/redirected to the > >appropriate view which contained meaningful information about the error. > > > >Although I have not yet seen it, I would have to believe the > diagram meant > >the view _indirectly_ accesses the model via the controller. > > > >robert > > > > > -----Original Message----- > > > From: Dan Cancro [mailto:[EMAIL PROTECTED]] > > > Sent: Wednesday, May 15, 2002 1:28 PM > > > To: 'Struts Users Mailing List' > > > Subject: RE: Application State == View or Business Logic > > > > > > > > > I thought that a view could access a model directly to > display the model's > > > state. There used to be a MVC2 diagram on the Struts site > that had a line > > > connecting the view directly to the model. Does Struts work > differently > > > now? That was a good diagram. I wish it was easier to find. > > > > > > Thanks, > > > Dan > > > > > > > -----Original Message----- > > > > From: Ted Husted [mailto:[EMAIL PROTECTED]] > > > > Sent: Wednesday, May 15, 2002 9:44 AM > > > > To: Struts Users Mailing List > > > > Subject: Re: Application State == View or Business Logic > > > > > > > > > > > > In remote applications, including Web applications, MVC is usually > > > > moderated by the Layers pattern, so that the View and the Controller > > > > interact and the Controller and Model interact, but the > View and Model > > > > do not interact. > > > > > > > > V <-> C <-> M <-> (persistent store) > > > > > > > > > > > > -- Ted Husted, Husted dot Com, Fairport NY US > > > > -- Developing Java Web Applications with Struts > > > > -- Tel: +1 585 737-3463 > > > > -- Web: http://husted.com/about/services > > > > > > > > > > -- > > > To unsubscribe, e-mail: > > > <mailto:[EMAIL PROTECTED]> > > > For additional commands, e-mail: > > > <mailto:[EMAIL PROTECTED]> > > > > > > > > >-- > >To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> >For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > > > >-- >To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> >For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
