CEN 4010 Class 5 0913 Introduction to Unified

CEN 4010 Class 5 – 09/13 Introduction to Unified Modeling Language (UML) cont • • • Project Review - Classes 4 Diagrams – – • • • statechart activity Modeling Concepts More on Diagrams Rational Rose Note: See example the course home page. CENuse 4010 case Class on 5 - 09/13

Overview of UML cont • There are four kinds of relationships in UML: 1. 2. 3. 4. • • Dependency Association Generalization Realization Dependency (between two things) – a change to one thing may affect the semantics of the other thing. Association – describes links i. e. , a connection among objects. CEN 4010 Class 5 - 09/13 2

Overview of UML cont • • Generalization (specialization/generalization) – objects of a specialized element (the child) are substitutable for object of the generalized element (the parent). Realization – a semantic relationship between classifiers, i. e. , a classifier (interface) specifies a contract to be carried out by another classifier (class). CEN 4010 Class 5 - 09/13 3

Example of Use Case Diagram Simple. Watch. User Read. Time Set. Time Watch. Repair. Person Use case diagram describing the functionality of a simple watch. Change. Battery CEN 4010 Class 5 - 09/13 4

Example of Class Diagram Simple. Watch 1 2 Push. Button Class Structure <class name> <attributes> <operations> 1 Display 1 1 1 2 1 Battery Time Details of the Time class CEN 4010 Class 5 - 09/13 5

Example of a Sequence Diagram Set_minutes use case CEN 4010 Class 5 - 09/13 6

UML Diagrams - Statechart • A statechart diagram shows a state machine that describes the behavior of an individual object. A state machine consists of states, transitions, events (things that trigger a transition), and activities (the response to a transition). • Statecharts focus on the external events that result in an object changing state. • Useful when modeling reactive systems. • Very useful when validating the specification of a system. CEN 4010 Class 5 - 09/13 7

Example of Statechart Diagram Statechart diagram for the Set. Time use case. CEN 4010 Class 5 - 09/13 8

UML Diagrams - Activity • An activity diagram is a special kind of statechart diagram that shows the flow from activity to activity within a system. • Used to model the functionality of the system w. r. t. the flow of control among objects. • Activities are states that represent the execution of a set of operations. CEN 4010 Class 5 - 09/13 9

Example of an Activity Diagram CEN 4010 Class 5 - 09/13 10

Modeling Concepts • System – an organized set of communicating parts designed for a specific purpose, or – a purposeful collection of components that work together to achieve some objective. • Subsystem – part of a system. Subsystems can usually operate as independent systems in their own right. • A component is a physical and replaceable part of a system that conforms to and provides the realization for a set of interfaces. CEN 4010 Class 5 - 09/13 11

Modeling Concepts cont • Modeling is a means for dealing with the complexity of systems and subsystems. • A rule of thumb is that each entity in a model should contain at most 7 +/- 2 parts. [Miller, 1959] • A view focuses on a subset of a model to make it understandable. • Logical view – used to visualize, specify, and document your decisions about the vocabulary of your domain and the structural and behavioral way things collaborate. CEN 4010 Class 5 - 09/13 12

Modeling Concepts cont • Physical view – used to construct the executable system. • Logical things live in the conceptual world, the physical things live in the world of bits i. e. , they can be executed on a machine. • Note, in UML several logical views are carried over to their physical counterparts. E. g. , an interface for a class (logical model) is carried over to the physical component that realizes it. CEN 4010 Class 5 - 09/13 13

Modeling Concepts cont • Terms: – – data type, abstract data type instance, object, class operations, attributes generalization, superclass, subclass, abstract class, • Falsification – Process of demonstrating that relevant details have been incorrectly represented or not represented at all. Contradiction! • Prototyping. CEN 4010 Class 5 - 09/13 14

More Use Case Diagrams • Recall: – Actors are external entities that interact with the system. E. g. , ATM user, bank teller, authentication server, central database. – Use cases describe the behavior of the system as seen from an actor’s point of view. • Use case characteristics: – describes a function provided by the system as a set of events that yields a visible result for the actors. – actors initiate a use case to access system functionality. CEN 4010 Class 5 - 09/13 15

More Use Case Diagrams cont • Use case characteristics cont: – use cases can initiate other use cases. – actors and use cases communicate i. e. , exchange information. • We will use the use case template provided on the web page. (Go through sections of template) • A scenario is an instance of a use case describing a concrete set of actions. • Use cases describe all possible cases. CEN 4010 Class 5 - 09/13 16

More Use Case Diagrams cont • A solid line in a use case diagram represents the communication between an actor and a use case. • In real applications some use cases are part of several other use cases. This is denoted by the <<include>> relationship. • A use can extend another use case by adding events. This is denoted by the <<extend>> relationship. • A use can specialize a more general one by adding more detail. CEN 4010 Class 5 - 09/13 17

More Use Case Diagrams cont Pages 47 -51 in text. Examples: <<extend>> Logon Update user info <<include>> Validate user Authenticate with. Password Track order General use case Authenticate with. Card Specialize use cases CEN 4010 Class 5 - 09/13 18

More Class Diagrams • Notation conventions: – Object names are underlined. – Class names start with an uppercase letter. – Object names are unique. • A link represents a connection between two objects. • An object diagram shows a set of objects and their relationships. (Requirements analysis) • A relationship is a connection among things. CEN 4010 Class 5 - 09/13 19

More Class Diagrams cont • A dependency is a using relationship that states a change in specification of one thing may affect another thing that uses it, but not necessarily the reverse. [Booch ’ 99] Department Dependency relationship name: string ssn. List: string Employee update(emp: Employee) print. List() CEN 4010 Class 5 - 09/13 20

More Class Diagrams cont • A generalization is a relationship between a general thing (superclass or parent) and a more specific kind of thing (subclass or child). A. k. a “is-a-kind-of” relationship. Note objects of the child maybe used anywhere the parent may appear, but not the reverse. [Booch ’ 99] • A child inherits the properties of it parents. • An operation of the child that has the same signature as an operation of the parent overrides the operation of the parent. CEN 4010 Class 5 - 09/13 21

More Class Diagrams cont Employee ssn: string name: string base class get. Name(): string get. SSN(): string Manager Clerk mang. ID: string get. Mang. ID(): string derived classes station: int get. Station(): int CEN 4010 Class 5 - 09/13 22