The 4+1 View Model

For this blog entry we read about the 4+1 view model and before I start talking about what it is and how it is used I need to make a little comparison with something which I have been taught since I got into this career, this is UML Diagrams, as I stated before we learn this in our first courses of our career and the idea behind them is that they give you an overview of how your code is connected, which functions deal with which other, which ones could be improved with classes and while this is a great tool which we have used a lot, there can be improvements and the 4+1 view model improves into the idea of the UML Diagrams using a different approach which I will explain now.

As we know from the reading software consists of 3 parts (main parts):

-       the first one is the structural elements of our codes and interfaces

-       The second one is the collaboration between all the structural elements

-       The third is how this structural element are composed and used into larger systems.

The 4+1 view model is designed to organize an application into what each person needs to see, what is important for them and most important, what they does not need to see and in an example a security engineer would only see the parts relevant to his work, an administrator would see other parts, a project manager would see other things and this is the beauty of this view model.

The views that the model has are the Logical View, the Process View, the Implementation View, the Deployment View and the use Case view and this views working together make a great way to see software and a different way of understanding it, I think it would be interesting to try this.

I started off by watching a short video titled The Six Blind Men, this short video shows that anyone can have a different opinion, and this opinion can be right, but if there is no moderator or intermediate then no one can join their ideas in order to take a correct conclusion. Afterward I read an article titled The Elephant and the Blind Programmers and this basically is based on the Six Bind Men story but now associated with the software area, and this is where 4+1 model takes importance because this model will be the intermediate so everyone can understand the concept/system and can make a better conclusion.

Basically, the model consists of 5 important areas/views:

• Logical View. It shows what sort of objects/classes we are going to be building for the product. 
• Implementation/Development View. It shows to the developer how the system is organized during the development.
• Process View. Describes the concurrency and synchronized aspects of the process and software.
• Physical View.  It shows how software and hardware are related. Architecture diagrams
• Use-Case View. This is the +1, also called scenarios, which describe is how the system interacts with users.

Let's go a bit more in depth with examples. It starts off on taking notes of requirements. What you're actually doing here is building user stories and use cases diagrams (scenario view). Then, you need to do the software analysis and models using tools of the UML so you can cover the areas of logical view and implementation view. Finally, you need to create a diagram or something that shows the architecture where the software is going to be stored. Having these on our documentation is going to be useful and having it easily and clearly specified will help understanding it in a glimpse.