URGENT SUGGESTIONS- j2ee WEB FRAMEWORK

Question

Hi All,
As a part of our part time project me and my friends are exploring on development of a j2ee web framework. For this we are exploring the behaviours of some famous frameworks such as STRUTS.
We are looking at the normal Controller model, The automatic httprequest to Java bean bindings and other such features.
We would like to hear more suggestions as to what
1. What all should be the salient features of a j2ee Web Framework.
2. Any feature that isnt present in the existing web frameworks but wud be a real value add if present.
Any other general suggestion about design of such frameworks etc are also welcome.
It would be great if all you guys give us your genuis feedbacks..
Thanks
Karthik

Answer 1

Sorry, I used up all my genuis feedback advice for the week. However, here are some ideas.
Struts framework is/was very popular but is rapidly being replaced by the Spring framework.
I dont believe you can just read some on-line articles on these frameworks because there is a lot of information to learn.
I suggest you buy a book on either framework and go through it cover to cover. Similiarly I suggest you read a JSP book first (you can look through them at the bookstore, then buy them on amazon.com cheaper).
I few quick suggestions about building your own framework before messing with a framework:
Ideally, you should have a separation of concerns between the layers (Model View Controller):
View = this is the JSP pages. Those pages should read all the information necessary to populate itself from objects placed in request scope. They should not contain business logic (such as instansiating java objects) or database logic (such as sql statements to fetch data from the database).
Control= this usually is a single servlet responsible for taking in all url browser requests (say, a JSP button update click), verifying the user is logged in, then calling up business logic to obtain data to populate the JSP page. It puts the data provided by the business logic in request scope for the JSP page to read, then dispatches to the correct JSP page. The control does not genereate html tags to put on the JSP page. The user should never directly call up a JSP page. All requests should go through the servlet to ensure you have a single class that verifies the user's login (security).
Model: The model consists of business logic and database logic. Often, these are separated into thier own layers as follows:
1) business logic: The control calls the business logic and passes all the data from the JSP page to it. It then determines what data to pass back to the control so it can pass it back to the JSP page. The business logic does not deal with the request scope (request is a presentation object), it does not call sql statements to talk to the database. Instead it calls database logic to actually get the data.
2) database logic: fetches data from the database for the business logic to use. It has sql. It has no business logic or presentation logic.
Lastly, I normally create a form object to hold all the data I read from the JSP page. Example: You have a JSP page called MyJspPage..jsp:
class MyJspPageForm{
public MyJspPageForm(HttpRequest request){
//get all data from the request scope that the JSP page put there
//have a bunch of get/set functions for the business logic to access the data.
I suggest creating a project based on the above ideas before you mess with a framework such as struts or spring. a lot of work has gone into creating those frameworks and they abstract away a lot of the low level code that I discussed above.