1 Team Skill 3 - Defining the System (Chapters of the requirements text) CSSE 371 Software Requirements and Specification Don Bagert, Rose-Hulman Institute of Technology September 20, 2005 Thanks to Mark Ardis and Steve Chenoweth for some of the slides included.

2 Outline  Use Cases  Organizing Requirements  Vision Document  Product Management

3 Use Cases

4 What is a Use Case?  Sequences of actions  Performed by system of interest  Observable result of value to a particular actor

5 Use Case Model - Development Steps 1. Identify the actors 2. Identify the use cases 3. Identify actor/use case relationships 4. Outline use cases 5. Refine use cases

6 1. Identify the Actors  Who uses the system?  Who gets/provides information from/to system?  Who supports the system?  What other systems interact with this system?

7 2. Identify the Use Cases  What are the intentions of each actor with respect to the system?  Give a descriptive name: Start with an action verb Describes goal or intent  Give a one-sentence description

8 3. Identify Actor/Use Case Relationships  Draw a diagram showing relationships between actors and use cases Eat foodBuy food Parent Child

9 4. Outline Use Cases  Describe sequence of events in basic flow (sunny day scenario)  Describe sequences of events in alternate flows (rainy day scenarios)

10 5. Refine Use Cases  Describe sequences of events for flows  Describe pre-conditions  Describe post-conditions  Fill in special requirements

11 Use Case Template A. Name B. Brief description C. Actors D. Basic flow E. Alternate flows F. Pre-conditions G. Post-conditions H. Special requirements

12 Microwave Example User Cook Food

13 Cook Food Use Case – Slide 1 of 4 A. Name: Cook Food B. Brief description: User places food in microwave and cooks it for desired period of time at desired power level. C. Actors: User

14 Cook Food Use Case – Slide 2 of 4 D. Basic flow: 1. User opens door and places food in unit 2. User enters time for cooking 3. User pushes start button 4. Unit cooks food 5. Unit beeps

15 Cook Food Use Case – Slide 3 of 4 E. Alternate flows 1. User cancels time before starting 2. User cancels cooking before finished 3. User selects reduced power level before pushing start button

16 Cook Food Use Case – Slide 4 of 4 F. Pre-conditions Unit is plugged in Unit is in ready state G. Post-conditions Food is cooked or user cancelled operation H. Special requirements Timer should display remaining time to finish while cooking Default power setting should be "high"

17 Organizing Requirements

18 Organization Techniques  Dividing requirements for complex systems into subsystems  Product Families A series of products with closely related requirements Product lines – a new way of viewing software products  Investing in infrastructure to build product families  Develop systematic approach to building flexible application generators  Commonality analysis – used to determine if use of a product line will be beneficial

19 Economics of Families Current Practice Number of Family Members Cumulative Cost Product Line Approach

20 Example Families  Toyota automobiles and trucks  IBM 360 computers  Software?

21 The Vision Document

22 Purpose  Every software project will benefit from having a Vision document.  The Vision document describes the application in general terms, including descriptions of the target market, the system users, and the application features.  The Vision document defines, at a high level of abstraction, both the problem and the solution.  It gives the development team “common goals and a common playbook.”

23 Vision Document Template 1. Introduction 2. User Description 3. Product Overview 4. Feature Attributes 5. Product Features 6. Exemplary Use Cases 7. Other Product Requirements 8. Documentation Requirements 9. Glossary

24 Product Management

25 Rationale  Every project needs an individual champion or a small champion team to advocate for the product.  In a software products company, the product manager plays the role of the champion.  The product manager drives the whole product solution: the application itself, support, user conveniences, documentation, and the relevant commercial factors.  The Product Manager does high-level tasks – Listens to all the stakeholders Negotiates amongst them Manages and funds project people Communicates features and releases to the outside world Advocates the product to everyone “Owns” the vision statement!

26 Product Manager in the Hierarchy Chart

27 Driving the Product Vision

28 A Product Manager’s Day  Plan scenarios in which products provide answers These pieces make the product manager’s vision!

29 Product Types from a Marketing POV  There are two major variations: A “custom” product for a particular customer or small group of customers – They often act directly as “external clients” A “general” product for a target market – An executive or the product manager is the “internal client” for these future customers