Final Notes on the UML

CS 123/231

UML Diagramming Techniques

Class DiagramsUse Case DiagramsInteraction Diagrams

Sequence diagramsCollaboration diagrams

State DiagramsOthers (e.g., Activity Diagrams,

Packages)

Activity Diagram

Represents sequence of activitiesDepicts condition, iteration, and

parallel activitiesWhen to use:

Analyzing use casesAlternate way of describing a use caseDepicting use case sequences/workflow

Describing method behavior

Activity Diagram Notation

Oval - activityStart and end buttonsLinks between ovals to depict

sequenceDiamond – conditional branch and

mergeBar – fork and join (concurrent

activities)

About Activity Diagrams

Helps in understanding system behavior, but …

It does not provide an object-oriented perspective!

Suggestion: just use as a tool to clarify complex sequential/parallel relationships between behavioral components

CRC Cards

Not really part of the UMLBut helps in construction of Class

Diagrams and Interaction DiagramsCRC: Class-Responsibility-

CollaborationRole-playing:

Team members represent classesEach member/class holds an index card

CRC Cards, continued

Team goes through each use case and role-play object interaction

Responsibilities (which end up being methods) are noted on the index card

Use of an index card is deliberateResponsibilities ought to be evenly distributed

across the classes that interactOverloaded classes become immediately

apparent

CRC Cards and UML Diagrams

Role-playing activity for each use case maps directly to interaction diagram construction

Each card provide class details (methods) for the class diagram

Package Diagrams

Recall: Architectural DesignDivide a system into subsystemsDepicted using a block diagram

OO alternative: Package DiagramsPackage <-> Subsystem

Package: group of classesDependencies between packages

Package Diagram Notation

Folder: PackageDotted arrow between folders:

dependency linkTwo variations

Abbreviated: name in folderDetailed: name on folder tab, rectangles

representing classes in folder area

Using the UML

Use the UML as a communication tool across the different stages of software engineering

Primarily a design tool but helpful in analysis as well

Important to note what stage or perspective you are in

Perspectives

Conceptual (analysis)Focus on domain and requirementsUse case diagram, high-level class

diagram, maybe some activity diagramsSpecification (design)

Focus on solution/programming detailsImplementation

Focus on code

Phases in theRational Unified Process

InceptionFeasibility StudyAnalysis

ElaborationAnalysisDesign

ConstructionImplementation and Testing