WA1105 Requirements Management and Use Cases Training and Courseware Course Outline 1. Introduction Topics What is a requirement? Types of requirements Important requirement concepts Requirement levels Requirement Categories What is requirements management? The cost of requirement errors The game plan towards building quality software Development Process The Rational Unified Process Inception Phase Example of Functional Requirements Example of Non-Functional Requirements Elaboration Phase Example of a Use Case Diagram Construction Phase Software Development Life Cycle with the RUP Requirement Gathering Roadmap The roadmap Step 1 – Analyze the problem Step 2 – Understand User Needs Step 3 – Define the system Step 4 – Manage the scope Step 5 – Refine the system definition Step 6 – Manage changing requirements 2. Problem Analysis and Understanding User Needs Topics What we plan to accomplish Problem Analysis Steps Analysis Steps Analysis Steps Stakeholders Definition of Actors Bring out the requirements Interviewing Step A: Interview every stakeholder Step B: Requirements Workshop Requirements Workshop Organizing requirement workshop Brainstorming Brainstorming- Idea reduction Storyboarding Use Cases Prototyping Step C: Identify Constraints Example - Given scenario Example (cont’d) Registration system – Problem statement Registration system – Problem statement(cont’d) List the stakeholders and users in the scenario List the actors Identify the constraints in the scenario Creating a constraint list 3. Vision Document & Managing scope Topics Topics - cont’d Vision document - Objectives Vision document - Scope Vision document - References Vision document - Positioning Vision document - Positioning (cont’d) Vision document - User Description Vision document - Product Overview Vision document - Feature Attributes Vision document - Product Features Vision document - Constraints Vision document - Quality Ranges Vision document - Precedence and Priority Vision document - Other Product Requirements Vision document - Documentation Requirements Example of Vision document Managing Scope Define a baseline Example of itemizing list of features requirements Setting priorities Example - Setting priorities Assessing effort Example - Assessing effort Adding the risk element Example - risk element Get customer agreement on scope Use iterative development process Plan Change Request (PCR) 4. Use Case Concepts Topics Use-Case Modeling Use case modeling steps What are Use Cases? Benefits of Use Cases Use Cases An Example requirement Identifying the actors involved in this requirement Write the use case for the above scenario Use case for the above scenario (contd) Classifying Use Cases A business use case Example of business use case (contn’d) Levels of use cases Examples of Summary level use cases Example of User goal level use cases Examples of Sub function use cases For use case modeling Use cases are only one part The Problem with Requirements Specifications Relationship Between Use Cases and Requirements Who are interested in use cases? An use case is a collection of scenarios To Use Case or not to … General Principles Scenarios Primary Scenarios Example of ATM use case Use Case interactions Finding Actors Finding Actors - continued Documenting Actors Where are the actors documented? Example - Actor profile table The Actor-Profile table for the course registration system: Actor-profile table – contd 5. Use Case Modeling – Use cases and supporting documents Topics Basic building blocks Basic Building Blocks of an Use Case Supporting documents Conceptual model Domain Model Supplementary Specification Goal List More use cases Documenting use cases Use Case Diagrams Scope The scenario we have been working on Identify the requirements that must be addressed by the system: Identify the use cases : Example - use case model Example - use case model Example - use case model for Registration system Lists used to manage scope – In/out list for the above example Lists used to manage scope – Actor/goal list for the above example Example - Use Case Specification Example - Use Case Specification (Contn’d) 6. Writing Use Cases Topics Actor Personalities Goal Levels Preconditions and Triggers Example of Preconditions Guidelines for writing main success scenario Extensions Use case linkages Sub Use Cases Example - Sub use cases with include & extend relations Quality Measures for Use Cases More Quality Measures Who should write use cases? Fully Described Use Cases How much detail? Completeness & Complexity 7. Use Case Formats Topics Formats to choose from Brief Description Format Bulleted Outline Format Conversational Format When to choose a format Tools CASE tools Reviewing Use Cases Style Style Guides “Do's and don'ts" to consider when describing an use case “Do's and don'ts" to consider when describing an use case 8. Miscellaneous Topics Topics Describing UI Wizards Make sure that the system is included Make sure that the user is included Wrong goal levels Make the use case easy to read Collect multiple pieces of data Do not forget the failure scenarios Stay away from internal system details Preconditions should be established by the system Check the following regarding conditions and preconditions CRUD Use Cases Contain the explosion Example - CRUD Use Case Specification Example - CRUD Use Case Specification (cont’d) 9. Supplementary Specifications Topics What is supplementary specifications Example of supplementary specifications Example of supplementary specifications (cont’d) Brief outline Functionality List Functional requirements: Non-functional requirements List of non-functional requirements Usability Usability Reliability List Reliability requirements: Performance Performance Supportability Design Constraints Practical Example of supplementary specifications Purpose Scope References Functionality - Course Registration System Usability - Course Registration System Reliability - Course Registration System Performance - Course Registration System Performance (cont’d) Supportability - Course Registration System Supportability (cont’d) Design Constraints Design Constraint - Course Registration System Design Constraint (cont’d)