Chapter 5

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

Rather than learn the detailed characteristics of every entity that we experience, we place these entities in more general classes and learn the characteristics of these classes. Helps to infer characteristics.

What is described in a context model?

Context models show what lies outside the system boundaries.

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

That most systems have a finite number of states and events (stimuli) cause a transition from one state to another.

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

They show the activities that make up a system process and the flow of control from one activity to another.

What is illustrated in a UML sequence diagram?

Used to model the interactions between the actors and the objects within a system (between actors/objects in a system and interactions between the objects themselves)

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

•A computation independent model (CIM) •A platform independent model (PIM) •Platform specific models (PSM)

What UML diagram types do you need to represent the essential features of a system?

•Activity diagrams show processing activities. •Use case diagrams show interactions between a system and its environment. •Sequence diagrams show interactions between actors and the system and between system components. •Class diagrams shows the object classes and relationships between these classes. •State diagrams show how the system reacts to internal and external events.

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

•Actors •Description •Data •Stimulus •Response •Comments

What perspectives should be used for developing models of a software system?

•External perspective, models the system context or environment. •Interaction perspective, models the interactions between a system and its environment, and between system components. •Structural perspective, models the system organization and the structure of the system data. •Behavioral perspective, models the dynamic, event-driven, behavior of the system. •Eternal perspective, models the meaning and relevance of the system.

What are the claimed benefits of model-driven engineering?

•Generating code automatically means that it is cheaper to adapt systems to new platforms. •Raises the level of abstraction in software engineering so that engineers no longer have to be concerned with programming language details or the specifics of execution platforms.