Integrating FRs and NFRs: A Use Case and Goal Driven Approach Presented by Chin-Yi Tsai

2 Outline Introduction Introduction A Review of UML Use Cases and the NFR Framework A Review of UML Use Cases and the NFR Framework The Goal – Oriented Analysis and Design Framework The Goal – Oriented Analysis and Design Framework The NFR Integration Process The NFR Integration Process Conclusion Conclusion

3 Introduction Function requirements using UML use cases as the main tool for requirement elicitation and modeling. Function requirements using UML use cases as the main tool for requirement elicitation and modeling. Propose a framework for integrating NFRs with FRs in the use cases model. Propose a framework for integrating NFRs with FRs in the use cases model. NFR framework (NFRs) NFR framework (NFRs) Use case (FRs) Use case (FRs) Association point Association point Actor, use case, actor-use case, and system boundary Actor, use case, actor-use case, and system boundary NFR scope propagation rules NFR scope propagation rules Define the scope of the NFR in the use case Define the scope of the NFR in the use case Integration Process Integration Process

4 A Review of UML Use Cases and the NFR Framework UML use cases UML use cases The NFR framework The NFR framework Goal-oriented approach for addressing NFRs Goal-oriented approach for addressing NFRs NFRs are represented as “ softgoal ” to be satisficed ”. NFRs are represented as “ softgoal ” to be satisficed ”. Softgoal Interdependency Graph (SIG) Softgoal Interdependency Graph (SIG)

Adopting the NFR Framework NFR Softgoal Name = Type[Topic] Goal Decomposition Operationalizaing Softgoal (design decision, strategy) Positive Contribution Negative Contribution Claim Architecture/design details UF of performing on-line transaction = UF of performing create service item, Approve price, submit price proposals Providing tech support greatly helps achieve user friendliness Implementing actual localization greatly hurts user friendliness. Why? Client-side scripting may be turned off, disabling localization feature.

6 The Goal – Oriented Analysis and Design Framework To provide precise context for NFRs To provide precise context for NFRs Propose that NFRs be integrated at certain points in the use case diagram call NFR Association Points. Propose that NFRs be integrated at certain points in the use case diagram call NFR Association Points. This framework specifies NFR scope propagation rules to ensure requirement completeness. This framework specifies NFR scope propagation rules to ensure requirement completeness.

7 With system E.g. Portability, Servicability, Maintainability NFR Association Points in the Use Case Model With actors E.g. Scalability: Actor system supports up to 10,000 concurrent requests; Actor is expert user. With use cases Ex. Performance, Reliability, Accuracy, Accountability With actor-use case associations E.g. Security, Confidentiality, User friendliness, Configurability, Adaptability

8 Propagation Rules: Actor-NFR Rules: An NFR associated with an actor is inherently associated with directly and indirectly specialized actors, in a more strict form Explicitly associated with A1 N2 (a more strict form of N1) propagated to directly specialized actor A2 N3 (a more strict form of N2) propagated to indirectly specialized actor A3 But not associated with generalized actor (A0) Example:

9 Propagation Rules: Use Case-NFR Rules: An NFR associated with a use case is inherently associated with directly and indirectly specialized and included use cases, in a more strict form. Explicitly associated with U1 N3 (a more strict form of N1) propagated to U3. N2(a more strict form than N1) propagated to U2. N8 (a more strict form than N2) propagated to U8 N9 (a more strict form of N3 propagated to U9

10 Explicitly associated with L1 Propagation Rules: Actor-Use Case Association NFR N2 (a more strict form of N1) propagated to L2 Rules: An NFR associated with an actor- use case association is inherently associated with the association between directly or indirectly specialized actors and use cases, in a more strict form. N3 (a more strict form of N2) propagated to L3

11 Propagation Rules: System - NFR Explicitly associated with system Rules: An NFR associated with the system inherently associated with all use cases, in a more strict form. N1 (a more strict form of N0) propagated to U1 N2 (a more strict form of N1) propagated to U2

12 FRs and NFRs Integration Process

Illustration using the Pricing System Identify Use Case Elements and Associated NFRs

Refine and Satisfice NFR and Operationalizing Softgoals