3 Unified Modeling Language - Mississippi State...

Software Architecture - Unified Modeling Language 1

Chapter 3 The Unified Modeling Language


Process Phase Affected by This Chapter

Requirements Analysis

Design

Implementation

Architecture Framework Detailed Design

Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.


Classes at Detailed Design

Responsibilities: -- describes each canister undergoing fabrication

+ display() - getNumOpenSlots() + setStatus()

+ numCanisters: int - numWafers: int - size: float

Canister Class name

Attribute: type

Operations

Place for comments

+:Visible from without

wafer

canister



Key Concept: à Representing a Class in UML ß

UML represents a class with a rectangle containing the class name. We display additional information within the rectangle as needed: Variables, methods, etc.



package of classes

abstract class

package MyPackage; abstract class MyAbstractClass . . . . package MyPackage; class MyDerivedClass extends MyAbstractClass { int att; . . . . . void myFunction( ReferencedClass r ) { . .. } }

MyDerivedClass att: int myFunction()

UML Notation … and … Typical Implementation

MyPackage

attribute operation

inheritance

MyAbstractClass



interface interface MyAbstractClass . . . . class MyClass implements MyInterface { . . . . . }

MyClass myMethod()

Interfaces UML Notation …… Typical Java Implementation

realization

MyInterface myMethod()



Key Concept: à Representing Inheritance in UML ß

UML represents inheritance and interface realization with an open triangle.



class MyClass { MyAggregatedClass ac; int att; . . . . . }

MyClass att: int myFunction()

MyAggregatedClass ac aggregation

Aggregation : UML Notation and Typical Implementation

1

ac composition Composed object exists only in

the scope of owner object



Key Concept: à Representing Aggregation in UML ß

Class A aggregates class B if A objects require B objects in a structural sense – typically with an instance variable. UML symbol is an open diamond.



class MyDependentClass { . . . . . void myFunction1( MyReferencedClass r ) { . .. } MyReferencedClass myFunction2( … ) { . .. } void myFunction3( … ) { MyReferencedClass m … } }

MyDependentClass att: int myFunction()

MyReferencedClass

Dependence : UML Notation … and …Typical Implementation

dependence (reference to a class)

parameter

or return type

or local variable type



Key Concept: à Representing Dependency ß

Class A depends on class B if A objects require B objects for their definition. In practice, this means that B appears in at least one method of A. UML representation: a dotted arrow.



class Employer { Employee[ ] employees; . . . . . } class Employee { Employer[ ] employers; . . . . . }

Employer Employee A

ssoc

iatio

n : U

ML

Not

atio

n an

d Ty

pica

l Im

plem

enta

tion

1..n 1..3 employs

is employed by



Customer Mail Application

CustomerMailApplication generateMail()

getCustomerTypeFromUser() main()

Customer createMail()

DelinquentCustomer createMail()

MountainCustomer createMail()

RegularCustomer createMail()

customer 1



Key Concept: à Use Cases ß

-- a sequence of actions taken by an application and its user.

The user takes one role.



Use Cases For Video Store Application

clerk

Check in

Check out

1. . . . .

Activate

1.  Actor hits any key. 2.  Application displays main

menu. …

stocker

Add video

1. … . . . . . . . . .

Precondition: Application has been activated

1.  Actor clicks “check out.” 2.  Actor swipes bar code. 3.  Application prompts for

rental duration. 4.  Actor enters duration. 5.  Application stores record. 6.  Application prints

customer’s account status.



Dispatcher

Warehouse worker

Use Case Generalization

& Usage

A. Application displays main options B. User selects icon

ControlApplication

Perform warehouse transaction

Modify Stock

«extends»

«uses»

A. Application displays main options 1. User moves cursor to stock icon B. User selects icon 2. Application displays stock window

(i). Application displays logo (ii). “Perform warehouse Transaction” use case. (iii) Application displays farewell screen (iv) Application shuts down



Beginning of Sequence Diagram for Check Out Use Case

Clerk :BarCodeReader

:Checkout

initiate() show()

:CheckoutOptionDisplay

} Step 2 of use case

Note 1

order

Note 3

doCheckout()

:MainScreen

read()

Note 2

{Step 3 of use case

Note 0



4. store()

2.3 show()

3. setDuration()

1. read()

Beginning of Sequence Diagram for Check Out Use Case User :BarCodeReader

doCheckout()

:MainScreen

Use case: 1. User swipes bar code 2. Application prompts for rental duration 3. User enters duration 4. Application stores record 5. Application prints customer’s account status

:Checkout 2.1 initiate()

:CheckoutOptionDisplay

:Account

2.2 create()

5. print()



Building a Sequence Diagram 1

1. Identify the use case whose sequence diagram you will build (if applicable).

2. Identify which entity initiates the use case –  the user, or –  an object of a class

•  name the class •  name the object

3. Draw a rectangle to represent this object at left top –  use UML object:Class notation

4. Draw an elongated rectangle beneath this to represent the execution of an operation

5. Draw an arrow pointing right from its top

myObject :MyClass



Building a Sequence Diagram 2

6. Identify which entity handles the operation initiated –  an object of a class

•  name the class •  name the object

7. Label the arrow with the name of the operation

8. Show a process beginning, using an elongated rectangle

9…… Continue with each new statement of the use case.

myObject :MyClass

myObject1 :MyClass1

operation()



Key Concept: à Sequence Diagrams ß

A sequence diagram shows the order in which methods of various objects execute.



States for OnlineShopper Class

Browsing ItemsChosen

CreditUnderValidation

CheckingOut

CreditDenied Complete

Incomplete



Conditions on Events

CreditUnderValidation Incomplete Hit Submit button

[credit card data incomplete]

[credit card data complete]



Hit checkout button

CheckingOut

State/Transition Diagram for OnlineShopper Class

Browsing ItemsChosen

CreditUnderValidation

CreditDenied Complete

Incomplete hit Submit button

[credit card data incomplete]

[credit card data complete]

put back last item

select item

hit OK validation received

denial received

hit OK

hit Quit

select item



Key Concept: à State Diagrams ß

Some applications or parts thereof are conveniently thought of as being in one of several possible states. UML state diagrams help us visualize these, and the events that cause transitions among them.



Activity Chart Notation Do Something

Do Something More

Do A Task Do Another Task

Do Even More

else [condition true]

} In parallel



A Class Model for Chaining

Rule addRule()

proveAntecedents() forwardChain()

Fact content

addFact() proveBack()

consequent

antecedents

static factList static ruleBase

Set Fact.factList to the known facts and a Rule.ruleBase to the known rules. Create Fact object soughtFact Execute soughtFact.proveBack( ruleBase );

1

1..n



Flowchart for soughtFact.proveBack()

Apply R.proveAntecedents()*

Report TRUE

Report FALSE

else

Another rule R exists with soughtFact as its consequent else

else

soughtFact in factList

Fact Rule

* Prove that every antecedent fact is true

proof succeeded



Specifications for Figure Drawing

q  Facilitate drawing stick figures

q  Drag to vicinity to auto-complete

q  Feet can be rectangles or ellipses

q  (Rest to be specified)

Releasing dragged figure anywhere in this area causes it to appear in position at end of left leg



Bad Attempt: “A Foot is Either an Ellipse or a Rectangle”

Foot

Ellipse Rectangle



Better Attempt: “A Foot is Either an Ellipse or a Rectangle”

RectangleFoot

Foot Rectangle Ellipse

EllipseFoot



Another Attempt: “A Foot is Either an Ellipse or a Rectangle”

Foot FootShape

Ellipse Rectangle



Best Attempt So Far: “A Foot is Either an Ellipse or a Rectangle”

Foot draw()

FootShape drawAsEllipse()

drawAsRectangle()

Ellipse draw()

Rectangle draw()



Class Model Showing All Dependencies

Foot draw()

FootShape drawAsEllipse()

drawAsRectangle()

Ellipse draw()

Rectangle draw()

GeometricFigure Area releaseCursor()

Leg

Position



Sequence Diagram for Figure Drawing Application

:FootShape :Foot

releaseCursor

drawAsEllipse*

:Ellipse

draw( aPosition )

:Area

draw ( GeometricFigure aGeometricFigure )

( Position aPosition )

( Leg aLeg, aGeometricFigure )

* or drawAsRectangle() …



Lesson Summary

q  Use Cases o  Actor / application

interactions q  Sequence Diagrams

o  Objects o  Sequence of methods

§  calling methods among objects

q  Class Models q  Activity Diagrams

o  Flow of control q  State Diagrams

o  States o  Transitions among states

§  caused by events

q  Dependency o  member method mentions

another class q  Association

o  structural o  e.g., sale / receipt o  Aggregation

§  common kind of association §  e.g. airplane / wing §  one-way §  “has-a”

q  Inheritance o  “is-a”

UML Models Relationships between Classes

3 Unified Modeling Language - Mississippi State...

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