i've doubt in the implementation pattern. according to the pet store application architecture in j2ee blueprints,jsp,javabeans and custom tags are the core of the view.From what i understand EJB tier comprises of the model.if in an application if we have a single controller servlet what exactly will it do. my understanding is it will accept client forwarded from jsp, instantiates the respective bean according to the kind of request and gives its context along with the model's state to the javabean. the model state can be presented to the user through the use of usebean tags is jsp. can anybody tell me whether this is correct or am i missing any crucial point. please respond to this as i need to know this urgently. thanks in advance.
Joined: Feb 07, 2001
please somebody reply to this. i need this. thanks in advance
Joined: Mar 09, 2000
Hi For additional information you should look up the "Model-2" architecture. In the mean time I'll explain. The JSP/HTML (View) layers send a request to a servlet which can dynamically instantiate an object depending on the request. (We'll call them Action classes). The action class is processed (Controller) by calling a method defined in your Action Class Interface. This process could be to lookup EJB Obects, or get information from a database (the Model) the controller then can continue performing more Functional Specifications (More Controller). The resulting information is then added to the 'HttpRequest" object and is dispatched back to another JSP (View). This shows a very circular pattern that is quite powerful and easily to manage and add functions to. You may also want to lookup the 'struts' product at jakarta.apache.org. This is a great example of a proper MVC architecture. (In my opinion that is) Hope this helps. ------------------ SOURCE CODE should be SURROUNDED by "code" tags. Click here for an example [This message has been edited by John Bateman (edited July 06, 2001).]
Actually, yes, you ARE missing an important point. The "useBean" tag doesn't grok EJBs - it's for traditional JavaBeans. EJBs require a naming context in order to be located/instantiated, and useBean doesn't support this.
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