NJIT Requirements To Design--Iteratively Chapter 12 Applying UML and Patterns Craig Larman Presented By :Satish Khanna

Objectives Motivate the transition to design activities. Contrast the importance of object design skill versus UML notation knowledge.

Introduction Following the UP guidelines, perhaps 10% of the requirements were investigated in inception, and a slightly deeper investigation was started in this first iteration of elaboration. Now we shift our emphasis toward designing a solution for this iteration in terms of collaborating software objects.

Iteratively Do the Right Thing, Do the Thing Right  The requirements and object-oriented analysis has focused on learning to do the right thing; that is, understanding some of the outstanding goals for the Next-Gen POS, and related rules and constraints.  In iterative development, a transition from primarily a requirements focus to primarily a design and implementation focus will occur in each iteration.

Didn’t That Take Weeks To Do? No, Not exactly. When one is comfortable with the skills of use case writing, domain modeling, and so forth, the duration to do all the actual modeling that has been explored so far is realistically just a few days. However that does not mean that only a few days have passed since the start of project. Many other activities such as proof-of-concept programming finding resources (people,software ….) planning,setting up the environment could consume a few weeks of preparations.

On to Object Design During object design, a logical solution based on the object-oriented paradigm is developed. The heart of this solution is the creation of interaction diagrams which illustrates how objects collaborate to fulfill the requirements. After-or in parallel with-drawing interaction diagrams,( design) class diagram can be drawn.

On to Object Design In practice,the creation of interaction and class diagram happens in parallel and synergistically, but their introduction is linear in this case study for simplicity and clarity.

Importance of Object Design Skill vs UML Notation skill  Drawing UML interaction diagrams is the reflection of making decisions about the object design.  The object design skills are what really matter, rather than knowing how to draw UML diagrams. Fundamental object design requires knowledge of :  Principles of responsibility assignment  Design patterns