Use Case Modelling

Question 1

What is the favoured technique in UML to capture functional requirements?

Answer 1

Use Case Modelling.

Question 2

What is a Use Case?

Answer 2

A Use Case describes how a user will use the proposed IT system to prvide some result of value to them in the context of their work.

Question 3

How should IT requirements be for a Use Case?

Answer 3

They should be user oriented, business goal focused, consistently specified.

Question 4

What are some facts in regards to Use Cases?

Answer 4

They are structured functional requirements, they are a description of the dialogue between the user and the system, they are expected to deliver value, the sum of the use cases is the system, they must be using a verb-noun phrase.

Question 5

What is the focus of Use Cases?

Answer 5

Always described from the actor’s POV, yeild a result of value for the actor, support activities in business processes, describe only interactions with the IT system, should not be confused with business processes.

Question 6

What is an Actor in a Use Case?

Answer 6

Representation of a named user role that interfaces with the system.

Question 7

What types of Actors exist in Use Cases?

Answer 7

Human and non-human actors.

Question 8

What are some charateristics of Use Case Actors?

Answer 8

They initiate the collaboration with the system and are external to the IT system.

Question 9

What are the three main symbols in a Use Case?

Answer 9

Actor, Use Case, and Association.

Question 10

What do Use Cases specify?

Answer 10

They specify the behaviour of the system, not how this is carried out (WHAT the system is meant to do).

Question 11

What are direction arrows used in Use Cases for?

Answer 11

To show an undirectional association, they improve the clarity of the diagram.

Question 12

What is a Primary Actor in a Use Case?

Answer 12

The actor triggering the use case and is seeking some benefit from the system.

Question 13

What is a Secondary Actor in a Use Case?

Answer 13

He doesn’t initiate the use case, he provides supporting information or confirmation, active collaboration will be required to further the goals of the primary actor.

Question 14

Why is a Use Case Description template used?

Answer 14

Once we have use cases described at a summary level and scope of the system agreed, descriptions can be written. They allow to have records.

Question 15

What are the component of the Use Case description template?

Answer 15

A unique reference, name (verb noun), brief description, triggers, actors, main flow.

Question 16

What is the Main Flow and what is an alternate flow in a use case?

Answer 16

The primary scenario will be the main flow and alternate flows will branf off and may-rejoin the main flow. Main flow needs to be understood to write an alternate flow.

Question 17

What is a Primary Scenario?

Answer 17

It describes the sequence of interatctions that take place between the primary actor and the system. It provides step by step, action generated, by the actor via the interface and the activities carried out by the system in response to those actions.

Question 18

What is a Main Flow UC Description?

Answer 18

A list of the activities order - Cockburn suggest this should be documented as a dialogue between the Primary Actor and the IT System.

Question 19

What happens once the primary scenarios for the Use Cases are understood?

Answer 19

Once understood and prioritised they can be analysed through the use of other UML techniques.