Chapter 5

1. How are activity diagrams used in describing the context of use of a system?

a. Activity diagrams, may be used to describe the business processes in which the system is used and the other systems which are also used in these processes.

1. What UML diagram types may be used to represent the essential features of a system?

a. Activity diagrams, which show the activities involved in a process or in data processing. b. Use case diagrams, which show the interactions between a system and its environment. c. Sequence diagrams, which show interactions between actors and the system and between system components. d. Class diagrams, which show the object classes in the system and the associations between these classes. e. State diagrams, which show how the system reacts to internal and external events.

1. What are the claimed benefits of model-driven engineering?

a. Allows systems to be considered at higher levels of abstraction b. Generating code automatically means that it is cheaper to adapt systems to new platforms.

1. What perspectives may be used for system modelling?

a. An external perspective, where you model the context or environment of the system. b. An interaction perspective, where you model the interactions between a system and its environment, or between the components of a system. c. A structural perspective, where you model the organization of a system or the structure of the data that is processed by the system. d. A behavioral perspective, where you model the dynamic behavior of the system and how it responds to events.

1. What are the three types of abstract system model that are recommended by the MDA method?

a. Domain models that identify the principal concerns in a system. They are defined using UML class diagrams and include objects, attributes and associations. b. Class models in which classes are defined, along with their attributes and operations. c. State models in which a state diagram is associated with each class and is used to describe the life cycle of the class.

What is the basic assumption that underlies event-driven modelling?

a. It is based on the assumption that a system has a finite number of states and that events (stimuli) may cause a transition from one state to another.

1. How is generalization used to simplify the models of a system with many similar objects?

a. Often useful to examine the classes in a system to see if there is scope for generalization. If changes are proposed, then you do not have to look at all classes in the system to see if they are affected by the change.

1. What is illustrated in a UML sequence diagram?

a. Show interactions between actors and the system and between system components.

1. What are the principal components of a textual use-case description?

a. The actors involved b. A description of interactions c. The data that is exchanges d. The stimulus that triggers the use case e. The response of the system f. Comments and other information

1. What is described in a context model?

a. The immediate external environment of the system defining the systems context and dependencies that a system has on its environment.