10-UseCaseDescriptions.pdf

ACS2913 Software Requirements Analysis and Design Instructor: David Tenjo EXTENDED REQUIREMENTS MODELING THE UNIVERSITY OF WINNIPEG - ACS 2913 - FALL 2023 1 Chapter Outline Use Case Descriptions Activity Diagrams for Use Cases The System Sequence Diagram—Identifying Inputs and Outputs SSD Notati...

ACS2913 Software Requirements Analysis and Design Instructor: David Tenjo EXTENDED REQUIREMENTS MODELING THE UNIVERSITY OF WINNIPEG - ACS 2913 - FALL 2023 1 Chapter Outline Use Case Descriptions Activity Diagrams for Use Cases The System Sequence Diagram—Identifying Inputs and Outputs SSD Notation Use Cases and CRUD Integrating Requirements Models SYSTEMS ANALYSIS AND DESIGN IN A CHANGING WORLD, 7TH EDITION – CHAPTER 5 ©2016. CENGAGE LEARNING. ALL RIGHTS RESERVED. 2 Previous chapters identified and modeled the two primary aspects of functional requirements: use cases and domain classes This chapter focuses on detail modelling for use cases to document the internal steps within a use case Overview actors, Fully developed use case descriptions provide information about each use case, including: stakeholders, preconditions, post conditions, the flow of activities and exceptions conditions Activity diagrams can also be used to show the flow of activities for a use case Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved. 3 Brief Use Case Descriptions A brief description can be used for very simple use cases, system to be developed is a small, wellunderstood application A simple use case would normally have a single scenario and very few—if any—exception conditions. A brief description does not document the internal processing since for simple use cases there are few steps. THE UNIVERSITY OF WINNIPEG - ACS 2913 - FALL 2017 4 Use Case Descriptions A brief description as shown in Chapter 3 for most use cases. Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved. Use For: •Simple Projects: Use brief use case descriptions for smaller, straightforward projects or features where a detailed breakdown may be overkill. •Quick Overview: When stakeholders, including developers, need a highlevel understanding of the feature's functionality, brief descriptions are more efficient. •Agile Development: In Agile development methodologies, where flexibility and adaptability are key, brief descriptions may be favored as they are less rigid. •Prototyping: During the initial stages of a project or when creating prototypes, brief use cases can help provide a quick overview of 5 functionality. •Fully developed use case descriptions are detailed documents for software features. •They provide a step-by-step view of user interactions with the system. •Descriptions include user actions, system responses, and special conditions. •They help developers understand and implement user requirements. •Valuable for design and development to meet user needs and expectations. Fully Develop Use Case Descriptions •Used For: • Complex Projects: Use fully developed use case descriptions for complex projects or features where a high level of detail is essential. This is particularly useful when dealing with intricate workflows and interactions. • Large Teams: In projects with large development teams or where the development process needs extensive documentation for clear communication, fully developed use cases are valuable. • Detailed Testing: When comprehensive testing and validation are critical, fully developed descriptions help testers understand the expected behavior indepth. • Regulatory Compliance: In industries with strict regulatory requirements (e.g., healthcare, finance), fully developed use cases are often necessary to demonstrate compliance. THE UNIVERSITY OF WINNIPEG - ACS 2913 - FALL 2016 6 Fully developed Use Case Descriptions Write a use case description for more complex use cases Typical use case description templates include: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Use case name Scenario (if needed) Triggering event Brief description Actors Related use cases (<<includes>>) Stakeholders Preconditions Postconditions Flow of activities Exception conditions Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved. 7 Fully Developed Use Case Description Use case: Create customer account SYSTEMS ANALYSIS AND DESIGN IN A CHANGING WORLD, 7TH EDITION – CHAPTER 5 RIGHTS RESERVED. 8 Use case name • Verb-noun Scenario (if needed) Use Case Description Details • A use case can have more than one scenario (special case or more specific path) Triggering event • Based on event decomposition technique Brief description • Written previously when use case was identified Actors • One or more users from use case diagrams Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved. 9 Related use cases <<includes>> • If one use case invokes or includes another Stakeholders • Anyone with an interest in the use case Use Case Description Details Preconditions • What must be true before the use case begins Post conditions • What must be true when the use case is completed • Use for planning test case expected results Flow of activities • The activities that go on between actor and the system • Usually the flow of activities is the most difficult part to develop, but also assists the analyst and the user to understand the requirements more deeply. Exception conditions • Where and what can go wrong Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved. 10 Another Fully Developed Use Case Description Example Use case Ship items SYSTEMS ANALYSIS AND DESIGN IN A CHANGING WORLD, 7TH EDITION – CHAPTER 5 ©2016. CENGAGE LEARNING. ALL RIGHTS RESERVED. 11 Activity Diagrams for Use Cases Activity diagrams were introduced earlier as a technique for documenting user workflows. They are easily understood diagram to document the workflows of the business processes. • Here we will used them to model processing as well. Activity diagrams are also an effective technique to document the flow of activities within a use case • They are are helpful when the flow of activities for a use case is complex THE UNIVERSITY OF WINNIPEG - ACS 2913 - FALL 2017 12 UML Activity Diagram for Use Case Create Customer Account Note: this shows flow of activities only SYSTEMS ANALYSIS AND DESIGN IN A CHANGING WORLD, 7TH EDITION – CHAPTER 5 ©2016. CENGAGE LEARNING. ALL RIGHTS RESERVED. 13 Activity Diagram for Ship Items Use Case Note: ◦ Synchronization bar for loop ◦ Decision diamond SYSTEMS ANALYSIS AND DESIGN IN A CHANGING WORLD, 7TH EDITION – CHAPTER 5 ©2016. CENGAGE LEARNING. ALL RIGHTS RESERVED. 14 UML Activity Diagram for Use Case Fill shopping cart Note: this shows use case with <<includes>> relationship SYSTEMS ANALYSIS AND DESIGN IN A CHANGING WORLD, 7TH EDITION – CHAPTER 5 ©2016. CENGAGE LEARNING. ALL RIGHTS RESERVED. 15 This chapter focuses on models to provide details of use cases Summary Fully developed use case descriptions provide information about each use case, including actors, stakeholders, preconditions, post conditions, the flow of activities and exceptions conditions Activity diagrams (first shown in Chapter 2) can also be used to show the flow of activities for a use case Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved. 16