Hi all , Just thought i send a acknowledgement all the comments so far have been very interesting thus i have a folder full of MCV prints . I find that reading the MVC material as well as other documentation has made getting the grips of Struts Implemetation of MVC easier to comprehend. Keep up the good work. Cheers Chuck Rodney Smith wrote: >Hi All, > >That was an interesting response from Ghoot, as I have several >documentations from the web including jakarta.apache had useful information, but I >feel >they fail in a detailed explanation, even though the MVC is the same, it very >daunting to me at the moment as I am writing documentation out for this and >there is such a wide range of response for Struts and MVC. >If Anyone on this list that can state the correct information MVC and Struts >frame work with details explanations for new persons like my self that just >want correct detailed information so a person off the street could read and >understand Struts. That is the secret i do beleive. > >Kind Regards >Rodney Smith > >>Does this confusion not stem from trying to describe Struts in an MVC >>context ? >> >>There are parallels between Struts and MVC, but Struts is not an MVC >>implementation ! MVC does not map exactly to Web/Layered Applications ! >>This is something there is so much misinformation around about, it's no >>wonder people get confused. >> >>Struts uses many Patterns and shares some principles with MVC, but thats >>where the similarities end. It is good to have a general understanding >>of the principles behind MVC, but it is easy to become confused when you >>try to force a fit. >> >>There is much more to the Struts Patterns than simply Model View and >>Controller. Unfortunately there is a plethora of articles around the >>web, discussing Model 2 style frameworks and implying an MVC >>implementation. While 'comparison' between the two is useful, in my >>experience, it leads to people not really understanding what MVC is - >>and therefore - finding their own implementation more difficult. >>Ultimately it also limits their real appreciation of something like >>Struts. >> >>This is not meant to be a criticism of any individual on this list ! >>Just my observations on an issue that is a hot topic in our >>organisation. >> >>It's time there was a good explanation of the differences between MVC >>and Frameworks like Struts, in a language suitable for the new breed of >>Web Application Developers ! >> >>I have avoided specific examples of the differences, because it can open >>a can of worms, and i certainly dont want to initiate a war of words. >> >>I would recomend that anyone unclear on the differences, posts to this >>list, and perhaps we can collectively produce a suitable explanation >>[something I am already working on internally]. >> >>Just to avoid confusion - I have nothing against MVC - it is a Framework >>Pattern with many strengths. It simply isnt an exact match for Web >>Aplpications - nor was it ever intended to be. Historically [last couple >>of years], it has been touted as an explanation for emerging Web >>Application Frameworks - but this has only led to untold confusion. >> >>Hope this doesnt offend anyone, maybe rather just initiates a wider - >>much over due discussion. >> >>Thanks >> >>Ghoot Emaho >> >>>-----Original Message----- >>>From: Rodney Smith [mailto:[EMAIL PROTECTED]] >>>Sent: 10 August 2001 14:07 >>>To: [EMAIL PROTECTED] >>>Subject: Re: MVC ..... Model... >>> >>> >>>Hi Ted, >>> >>>Thanks for the information, but that still leaves many >>>options or a lot of >>>grey areas with my understanding, firstly is it possible to >>>show three e.g. of >>>architects with 3 / 5 / 7 of application layers please, text >>>or diagrams so >>>I know what you are referring two. >>> >>>>The MVC paradigm has been around for a while, and the >>>> >>>meaning of "model" >>> >>>>can be a little fuzzy. >>>> >>>>Right now, architects tend to see applications, and especially Web >>>>applications, as being in several layers. Sometimes 3, >>>> >>>sometimes 5 or >>> >>>>more. >>>> >>>The Container??? are you referring to the MVC as the container? >>>This needs to be explained a little better in basic terms as >>>'using some JSP >>>rendering engine' is something out in space to me. Are you >>>referring to view >>>'JSP'or is there a middle man inbetween all this. I have to >>>admit that all >>>the diagrams an information that I have read till this day >>>has always referred >>>to the request going to the ActionServlet'controller' for >>>delegation, but it >>>is important for me to know the structural side of Struts and >>>to be able to >>>answer questions with in my firm, on why and where this goes from the >>>request. >>> >>>>A request for logon.jsp would not actually go to the >>>> >>>ActionServlet. The >>> >>>>container the application runs within would handle that >>>> >>>directly, using >>> >>>>some JSP rendering engine. >>>> >>>OK, in a MVC is the actionform located in the view 'jsp' >>>section of the MVC? >>>If a request was going to be sent, it must go to the MVC so >>>when it arrives >>>it must hit a destination or does this hit the web.xml which >>>then shoot the >>>request to the actionservlet controller? >>> >>>>The ActionForm bean is an adapter between HTTP and the rest of your >>>>application. It is really part of the presentation layer, or view. >>>> >>>I understand that the validation needs to close to the client >>>side, so the >>>secret is, is that done by the web.xml before going into the MVC? >>> >>>>Whether the validation belongs to the presentation layer, >>>> >>>or elsewhere, >>> >>>>can be debated. As a practical matter it should be done as >>>> >>>close to the >>> >>>>client as possible. A good approach is to use the new >>>> >>>Validator servlet, >>> >>>>which can be programmed from a configuration file, and >>>> >>>avoids embedding >>> >>>>model concepts in the view. >>>> >>>>The "model-state" validations, like whether a username and password >>>>match, would take place in the Action, and would usually >>>> >>>need to access >>> >>>>the model. Here the Action is an "interface layer", between >>>> >>>the view and >>> >>>>the model. If this secondary validation fails, the Action >>>> >>>can return the >>> >>>>ActionForm bean to the view. >>>> >>>After the form bean has been validated at the start????, Does >>>this mean that >>>formbean and the action is located inbetween the view and the >>>model and when >>>the validation is complete by the action it will get the >>>information from >>>the model, which holds the EJB and DB2 and then the action >>>after receiving the >>>data, then forwardmapping to the actionservlet controller, >>>then to the view >>>'JSP' then back to the brower 'client' >>> >>>Ted if you can simplify these request it would be good, >>>Thanks for your time and effert. >>> >>>Kind Regards >>>Rodney Smith. >>> >>>>Once validation is complete, the properties of the >>>> >>>ActionForm should be >>> >>>>transferred to another object, that would definitely belong to the >>>>model. >>>> >>>>-- Ted Husted, Husted dot Com, Fairport NY USA. >>>>-- Custom Software ~ Technical Services. >>>>-- Tel +1 716 737-3463 >>>>-- http://www.husted.com/about/struts/ >>>> >>>> >>>>Rodney Smith wrote: >>>> >>>>>Hi All, >>>>> >>>>>Firstly, thanks Fiona for the feed back on your >>>>> >>>experiences with your >>> >>>>>project..... it is really good to read of the problems >>>>> >>>that has occured >>> >>>>and how you >>>> >>>>>over come them and especially how you learnt from that >>>>> >>>project...and >>> >>>>>especially your opinon on how to approach a web application. >>>>> >>>>>I would like to know when a request 'logon.jsp'goes to >>>>> >>>the actionservlet >>> >>>>and >>>> >>>>>this is delegated to a form bean to be instantiate, is >>>>> >>>this form bean >>> >>>>part >>>> >>>>>of the controller 'actionservlet' or is the form bean a >>>>> >>>part of the >>> >>>>'model'? >>>> >>>>>The question is, is the form bean and action,both stored >>>>> >>>in the model?? >>> >>>>and >>>> >>>>>if the logon is validated correctly. The'Model'with the >>>>> >>>form bean and >>> >>>>action >>>> >>>>>within could get information from e.g. DB2 or EJBs etc >>>>> >>>which is outside >>> >>>>of >>>> >>>>>the MVC. >>>>>Is there 3 sections to web application.... >>>>> >>>browser/MVC/EJB & DB2 etc.. >>> >>>>is >>>> >>>>>that correct? >>>>> >>>>>Thanks for your time and have a great day. >>>>> >>>>>Kind Regards >>>>>Rodney Smith >>>>> >>>>>-- >>>>>Sent through GMX FreeMail - http://www.gmx.net >>>>> >>>-- >>>Sent through GMX FreeMail - http://www.gmx.net >>> >
