UML Diagrams: Class Diagrams The Static Analysis Model Instructor: Dr. Hany H. Ammar Dept. of...

UML Diagrams: Class Diagrams

The Static Analysis Model

Instructor: Dr. Hany H. Ammar

Dept. of Computer Science and Electrical Engineering, WVU

outline

The Requirements Model and the Analysis model The Static Analysis Model – The Analysis Process

The Conceptual Level - Identifying the Classes of Objects (Step 6 Requirements Elicitation Process: Identify Initial Analysis Objects)

The Analysis Level – Identifying Class relationships, class attributes, and class operations

Examples

UML Development - Overview

PROGRAM

ACTORS

ANALYSISSpecify Domain Objects

Detailed DESIGN

IMPLEMENTATION

DATA

DICTION

ARY

TimeUSE CASES

ANALYSISCLASS DIAGRAM(S)

IMPLEMENTATIONActivity DIAGRAMS

System/ObjectSEQUENCEDIAGRAMS

OPERATION CONTRACTS

StateChart DIAGRAMs

DEPLOYMENT DIAGRAMSUBSYSTEM CLASS/OR COMPONENT

DIAGRAMS

Architectural DesignIncludeDesign Objects

ObjectDesign

SCENARIOS

REQUIREMENTSELICITATION

DESIGN DIAGRAMS

IMPLEMENTATIONCHOICES

DESIGN SEQUENCE DIAG.

RequirementsEngineering

The Requirements Model and the Analysis Model

Static Analysis Dynamic Analysis

Functional/ NonfunctionalRequirements

Use Case Diagrams/Sequence Diagrams(the system level)

- Class Diagrams- State Diagrams/Refined Sequence Diagrams (The object level)

Requirements ElicitationProcess

The AnalysisProcess

Static ModelingClass DiagramsA Class is defined as

–Real world entity type about which information is stored–Represents a collection of identical objects (instances)–

Described by means of attributes (data items)–Has operations to access data maintained by objects–Each object instance can be uniquely identified

Relationships between classes–Associations–Composition / Aggregation–Generalization / Specialization

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The Static Model

Defines the static structure of the logical model

Represents classes, class hierarchies using packages, classes, and their relationships,

Evolve in three phases the conceptual phase, the analysis phase, and the design phase.

The conceptual Level

At the conceptual phase, classes are defined based on the classes found in the problem domain descriptions (based on the objects identified in step 6 in the Requirements Elicitation Process)

A context class diagram is defined first, where the system under development is represented by one package and external classes representing the actors

Context Class DiagramDefines the Boundary of the system

<<external>>Input Devices

System under development

<<external>>Output Devices

Specify the classes of the external input/output devices and other actors (users, other systems, etc.) and the system classes

<<external>>Other Actors


The system package is defined by a diagram representing the main classes and interface classes to external classes

Each subsystem is represented by a class diagram defining the classes of objects needed to realize the use cases defined in the use case diagrams

The stereotype words <<external>> or <<actor>> are used to specify external classes or packages

Names of external packages should reflective of the classes defined in the package


Identify the system classes as Interface objects, Monitors objects, controllers objects,

Monitors

<<Interface>>Input_devices

or actors Controllers

<<Interface>>Output_devices

or actors

Example of System packages

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The Analysis Level

At the analysis level, class diagrams are refined by adding relationships between classes, attributes and methods depicting how objects of the static view are used to realize use cases in sequence diagrams

Emphasis is placed on distributing behavior, resolving software interfaces, and identifying generalization relationships that will maximize the effectiveness of the object model

The Class Diagram Notation Identify classes, attributes of each class, and

operations of each class Classes, their attributes and methods are specified

based on the objects needed to realized use case and interfaces to external entities

DetailedAttributes,Data types,And operations Are defined/refinedDuring design

Identify Class relationships

PilotCommands

AircraftControl

Association

Aggregate/Whole

Aggregated/Part

Aggregation (hollow diamond)/Composition (solid diamond)

Child

Parent

Generalization

Associations Between Classes

Associations between classes are generally shown as solid lines connecting the associated classes.

A notable exceptions to the solid line rule are the use of dashed lines to depict dependencies as special case of association,

Associations

Association is –static, structural relationship between classes

–E.g, Employee works in Department – Multiplicity of Associations

Specifies how many instances of one class may relate to a single association, Company hasPresident

– 1-to-many association, Bank managesAccount– Optional association (0, 1, or many) –Customer

ownsCredit Card instance of another class– 1-to-1 – Many-to-Many association –Course has Student, and

Student attends Course

Dependency: A Special Case of AssociationDependency

RequestHandler ResponseHandlerTimerEvent

CommandManager

CommandManager (Client class) depends on services provided by the other three server classes

Client

Aggregation Relation

Aggregation – A hollow diamond is attached to the end of the path to indicate aggregation. The diamond is attached to the class that is the aggregate. Aggregation provides a definitive conceptual whole part relationship

Aggregation Example

Composition: A Special Case of Aggregation

Composition is shown as a solid filled diamond, with the diamond attached to the class that is the composite. Composition is a form of aggregation that requires coincident lifetime of the part with the whole and singular ownership; i.e. the part is owned by only one whole and is deleted when the whole is deleted

+ sendPacket(pk: const cmd_pktCToCHeader*)

MQSendPacketMQWrite

Composition example

Aggregation vs Composition

Generalization/Specialization Relation Generalization is shown as a solid-line

arrow from the child (the more specific element) to the parent (the more general element) this type of relationship is also called inheritance.

Should be used to define class hierarchies based on abstraction

Generalization/Specialization Relation

Multiplicity of Relationships

Multiplicities

Meaning

0..1zero or one instance. The notation n . . m

indicates n to m instances.

0..* or *no limit on the number of instances

(including none).

1 exactly one instance (the default)

1..* at least one instance

Example of identifying Class Multiplicities,Attributes and operations

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Examples

Recall the Digital Sound Recorder Case Study Requirements Model

The Sound RecorderAnalysis Level Class Diagram

Emergency Monitoring System

The ATM Banking System

Example of Software Architecture Using UML2

SATELLITE CONTROL SYSTEM Architecture

A Simple Example of Software Architecture Using UML2

SATELLITE CONTROL SYSTEM Architecture

Example: Auto Cruise Controland Monitoring (The Cruise Cont. Subsys)

Example: Auto Cruise Controland Monitoring (The Monitoring Subsys)

Example of a Design Level Class Diagramhttp://www.codeproject.com/library/WinSNMPWrapper.asp?df=100&forumid=216441&exp=0&select=1259211

UML Diagrams: Class Diagrams The Static Analysis Model Instructor: Dr. Hany H. Ammar Dept. of...

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