WebSphere Application Server - IBM Redbooks

Input Page
(View)
Display Page
(View)
Figure 2-7 Model 2 architecture application flow
2.3.3 MVC architectural pattern
1
Request
Response
5
Serlvets
(Control)
Display Page
JSP
(View)
Model 1 versus Model 2: It is not the intention of this publication to single out
any one model as being better than the other. For the purposes of WebSphere
Application Server - Express and the targeted market of WebSphere
Application Server - Express, the Model 1 architecture is better suited. As
mentioned earlier, Model 1 architecture lends itself towards small projects that
can be developed quickly or when development teams do not have strong
Java servlet skills. That said, it is important to note that using the Model 1
architecture will hinder future scalability of applications. Extending the
application using Model 1 architecture becomes difficult since the page
presentation is so tightly coupled to the business logic. If a project is planned
for future growth, then a Model 2 or MVC architecture is recommended and
encouraged. It may be beneficial to “pay now versus pay later” to gain the
flexibility provided by the MVC design pattern.
The model-view-controller architectural pattern was conceived in the mid-1980s
by developers of the Smalltalk-80 GUI library. It has since then been extensively
applied in most object-oriented user interface and application control toolkits. It
has also been generalized as a pattern for implementing the separation of
concerns among application layers in general, not only the three originally
proposed layers.
According to the MVC pattern, a software component (an application, a module,
and so forth) should separate its business logic (the model) from its presentation
(the view). There are many reasons for this requirement, among which are the
following.
28 IBM WebSphere Application Server - Express V5.0.2 Developer Handbook
3
Interactive
2
4
Application Server
JavaBean
(Model)
Database