Requirements Validation with Enactable Models of State-based Use Cases

Chin-Yi Tsai

2

Outline

• Introduction• Dependencies in Use Case Specification-a case study• Experiences from the Study• Conclusions

3

Introduction• UML use case for requirements specification.

Authoring guideline for use case

• Different writing styles??? common writing scheme is important

• This paper To enhance use cases for the specification of interdependencies between stakeholder requireme

nts

• To enhance the explicit consideration of dependencies amongst use case events as a mechanism for validation.

• The traditional way of specifying interactions in systems is the use of a process algebra

• Constructing state-based business process models using the process modelling language RolEnact

• Producing enactable business process models depicting role interactions, this approach was found to bridge the communication gap between process modellers and business stakeholders, hence enhancing shared understanding.

4

Dependencies in Use Case Specification-a case study

• Use case description of the client-server connection process1. Client looks-up the Domain Naming Service

2. Client creates a connection Socket

3. Client connects to server

4. Server requests login data

5. Client sends login data

6. Server authenticates login data

• Most authors of use case specification seldom consider dependencies The presumption normally is that events follow a time-order dependency

• However, most control system are complex

5

Dependencies in Use Case Specification-a case study (Cont’d)

• Augmentation of use case events with pre and post conditions to explicitly determine whether the sequence of events in the use case is correct, and provide a mechanism for revising to correct any flaws

• DependenciesAmong eventsAcross multiple use case

6

Dependencies among Events

7

8

• A client’s network setup must be initialized by the Scheduler to ensure that any previous network activity by client does not hamper connectivity to different server application.

9

Dependencies Across Multiple Use Cases

• Association between actors in a use case or across use cases are not allowed

10

Conclusions

• Highlighting the implication for the lack of explicit consideration of dependencies in use case specification.Dependencies among eventsDependencies across multiple use cases

• Investigation of dependencies issues provides greater comprehension of both the problem domain and the behaviorVital to requirements validation

• Enactable approach that provides rigour in specification, and enhances communication during enaction.