Details of UML and Unified Process Koichiro OCHIMIZU School of Information Science JAIST

Details of UML and Unified Process

Koichiro OCHIMIZU

School of Information Science

JAIST

Use-Case View

Use-CaseView

ConcurrencyView

LogicalView

DeploymentView

ComponentView

H.E. Eriksson and M. Penker, “UML Toolkit” John Wiley & Sons, Inc.

Use Case Model

Use Case Model : A use case model represents the functional requirements and consists of actors and use cases. A use case model helps the customer, users, and developers agree on how to use the system.

Actor: An actor is someone or something that interacts with system.

System: Black box provided with use cases

Use Case: A use case specifies a sequence of actions 　that the system can perform and that yields an observable result of value to a particular actor.

I. Jacobson, G.Booch, J.Rumbaugh,”The Unified Software Development Process”, Addison Wesley, 1999.

Development of Use Case Model

• Defining the System• Finding Actors and Uses Cases• Use Case Descriptions• Defining Relationships between Use

Cases• Verify and Validate the Model


What is an Actor ?• An actor is someone or something that Interacts

with the system.• The actor is a type ( a class), not an instance.• The actor represents a role, not an individual user

of the system.• Actors can be ranked. A primary actor is one that

uses the primary functions of the system. A secondary actor is one that uses secondary functions of the system, those functions that maintain the system, such as managing data bases, communication, backups, and other administration tasks.


Finding Actors• Who will use the main functionality of the system ?• Who will need support from the system to do their

daily tasks ?• Who will need to maintain, administrate, and keep

the system working (secondary actor) ?• Which hardware devices does the system need to

handle ?• With which system does the system need to interact ?• Who or what has an interest in the result (the value)

that the system produce ?


What is a Use Case ?• A use case represents a complete functionality as

perceived by an actor.• A use case is always initiated by an actor.• A use case provides values to an actor.• A use case is complete.• Use cases are connected to actors through

associations (communication association).• A use case is a class, not an instance. A

instantiation of a use case is called a scenario.– Signing Insurance (Use Case)

– John Doe contacts the system by telephone and signs for car insurance for the Toyota Corolla he just bought. (scenario)


Finding Use Cases

• Which functions does the actor require from the system ? What does the actor need to do ?

• Does the actor need to read, create, destroy, modify, or store some kind of information in the system ?

• Does the actor have to be notified about events in the system, or does the actor need to notify the system about something ? What do those events represent In terms of functionality ?

• Could the actor’s daily work be simplified or made more efficient through new functions in the system ?


Logical View

Use-CaseView

ConcurrencyView

LogicalView

DeploymentView

ComponentView


A Simple model of an insurance business

Insurancecompany

Insurancecontract

Customer1 0..* 0..* 1..*


Finding Classes• Do we have information that should be stored or analyzed? 　

If there is any information that has to be stored, transformed, analyzed, or handled in some other way, then it is a possible candidate for a class. 　 The information might be concepts that must be always be registered in the system or events or transactions that occur at a specific moment.

• Do we have external system ? If so, they are normally of interest when we model.

• Do we have any patterns, class library, components ? If we have them from earlier projects, colleagues, or manufacturers, they normally contain class candidates.

• Are there devices that system must handle ?• Do we have organizational parts ?• Which roles do actors in the business play ? There roles can be

seen as classes; for example, user, system operator, customer, and so on.


Visibility

• + public referenced from classes other than the one in which they are defined– It violates Information hiding principle

• - private cannot access it from other classes• # protected can access it from sub classes

Invoice

+ amount : Real+ date : Date+ customer : String+ specification : String- administration : String


Default values

• Assigned at the same time an object of the class is created

Invoice

+ amount : Real+ date : Date = Current date+ customer : String+ specification : String- administration : String = “Unspecified”


A class-scope attribute or a class variable

• A class variable (underlined) is shared by all objects of the class

Invoice

+ amount : Real+ date : Date = Current date+ customer : String+ specification : String- administration : String = “Unspecified”- number of invoices : Integer


Property string

• Property string show the possible values explicitly

Invoice

+ amount : Real+ date : Date = Current date+ customer : String+ specification : String- administration : String = “Unspecified”- number of invoices : Integer+ status : Status = { unpaid, paid}


Java implementation

public class Invoice{ public double amount; public Date date = new Date(); public String customer; static private int number_of_invoices = 0;

// Constructor, called every time an object is created public Invoice() { // Other initialization number_of_invoices++; Increment the class attribute } // Other methods go here};


Signature

• Signature: a return-type, a name, zero or more parameters

Car

+ registration number : String- data : CarData+ speed : Integer+ direction : Direction- administration : String

+ drive(speed: Integer, direction: Direction)+ getData(): CarData


Class-scope operation

• Access class-scope attributes• Creation of objects

Figure

size : Sizepos : Positionfigcounter : Integer

draw() getCounter(): Integer


Visibility of Operation 　

Figure

size : Sizepos : Position

+ draw()+ scaleFigure(percent: Integer = 25)+ returnPos(): Position


Default values of parameter

• figure.resize(10,10) percentX=10, percentY=10

• figure.resize(37) percentX=37, percentY=25

• figure.resize() percentX=25, percentY=25

Figure

size : Sizepos : Position

+ draw()+ resize(percentX: Integer = 25, percentY: Integer = 25)+ returnPos(): Position


Java implementation

Figure

- x: Integer = 0- y: Integer = 0

+ draw()

Figure fig1 = new Figure();Figure fig2 = new Figure();fig1.draw();fig2.draw();

public class Figure{ private int x = 0; private int y = 0;

public void draw() { // Java code for drawing the figure }};


UML notationsRepresentation of Relationships between Classes

Dependency

Navigable Association

Association

Generalization

Aggregation: whole-part association

Composition: the same life span

G.Booch, J.Rumbaugh, I. Jacobson , ”The Unified Modeling Language User Guide”, Addison Wesley, 1999.

Multiplicity

Person Car0..*1..*

Person Car0..*owns

owned by

owns


A class diagram describing an Insurance business

Customer

1..*

Insurance Policy

0.. １

Insurance contract

InsuranceCompany

1

1

0..*

0..*


Computername: String

memory: Integer

0..* 1..*Authorname: Stringage: Integer

Use

Bob’s PC: Computer

name = “ Dell466”memory = 64

Bob:Author

name = “Bob J”age = 32

Object Diagram


Recursive Association

Node

Connects

*

*

Person

married to

wife

husband


Component

Operation()Add(Component)

Remove(Component)GetChild(int)

Composite

Client*

Leaf

Operation()

E.Gamma, R.Helm, R.Johnson, J.Vlissides,”Design Patterns”, ADDISON-WESLEY, 1995.

Clients use the Component class interface to interact with objects in the composite structure. If the recipient is a Leaf, then the request Is handled directly. If the recipient is a Composite, then it usually forwards requests to its child components, possibly performing additional operations before and/or after forwarding.

CompositeOperation()

Add(Component)Remove(Component)

GetChild(int)

forall g in children

g.Operation()

children

Object Diagram

aComposite

aCompositeaLeafaLeaf

aLeafaLeafaLeaf

aLeaf

E.Gamma, R.Helm, R.Johnson, J.Vlissides,”Design Patterns”, ADDISON-WESLEY, 1995.

Java Implementation

// Insurance_company.java filepublic class Insurance_company{ /* Methods */// Insurance_companyVector is a specialization of the // Vector class ensuring hard typing. Vector is a standard// Java class for dynamic arrays. private Insurance_contractVector contracts;};

// Insurance_contract.java filepublic class Insurance_contract { /* Methods */ private Insurance_company refer_to};

InsuranceContract

InsuranceCompany

1 0..*

refers to

contracts


Qualifier

Figure*Canvas

FigureCanvasfigure ID

“one to many” to “one to one


OR-association

Person Company

0..*Insurancecontract

Insurance company

1

0..

0..*

1..*1..*

Person Company

0..*Insurance contract

Insurancecompany

1

0..

0..*

1..*1..*

{or}

An insurance contract cannot have associations to both company and person at the same time


Ordered Association

Insurance contract

0..*

1..*

{ ordered }


Customer

Association Class

ElevatorControl

Button

Elevator

Queue

*

3

A class can be attached to an association


The association class is not connected at any of the ends of the association

Ternary Association

Person

Insurancepolicy

Insurancecontract

Insurance company

1 0..*

1..*

0.. １

0..*

policyholder


What is an Aggregation ?

• Aggregation is a special case of association• “whole-part”, “is-part-of”• Special kinds of aggregation

– aggregation

– Shared Aggregation

– Composition Aggregation

Aggregation

Composition: The part has the same life span with the whole


Aggregation

Warship*Navy

This example is not so good.

Contains


Shared Aggregation

PersonTeam

A team is composed of team members.

One person could be a member of many teams.

Members

**


Composition Aggregation

Window

*

*

*

Text

Listbox

Button

Menu

*


Another Expression of Aggregation

Window

*

*

*

*

Text

Listbox

Button

Menu

Text

Listbox

Button

Menu

Window

*

*

*

*


Generalization

• Associations and Aggregation describe structure of the problem domain which we are interested in.

• Generalizations describe concepts which are common to several problem domains.

Property

(reusability)

Problem Fitness

Vehicle

Car Boat

Generalization and Association

stockproblem domain2

class drawer{ }

class stock{ }This yearApril

drawer

purse drawer money stock

A BProblemdomain3

class Ａ extend{ }

class B extend{ }Next year

purse moneyproblem domain1

class purse{ }

class money{ }Last yearMay

container content

A B

Inheritance

• Class inheritance

• Interface Inheritance

Combination of Inheritance and Aggregation

Figure{abstract}

position: Posdraw(){abstract}

Canvas

Circle

draw()

Line

draw()

Group

draw()

Polygon

draw()

consists of

*

consists of *

consists of *


Java Implementation

Figure{abstract}

position: Posdraw(){abstract}

Group

draw()

Polygon

draw()

*

abstract public class Figure{ abstract public void draw(); protected Pos position;};

public class Polygon extends Figure{ public void draw(); { /* draw polygon code */ }};


Constrained Generalization

Class A

Class B Class C

{constraint1, constraint2, … ,}


Overlapping

Disjoint

Complete

Incomplete

Overlapping and Disjoint

Vehicle

Car Boat

Amphibian

{overlapping}


Complete and Incomplete

Person

Man Woman

{Complete}


Refinement relationship

AnalysisClass

Design Class

• A refinement is a relationship between two descriptions of the same thing, but at different levels of abstraction.

• It can be also used to model different implementations of the same thing.

• Support Configuration Management.

• Support traceability In the model.


Derivation

Car hirecompany

• can be computed from other associations and attributes.

• The VIP customers are a derived association when company makes contracts with many customers.

Hire contract

Customer

0..*

1

1

0..*

*

/ VIP customer


Derived Attribute

Article

cost pricesales price

/profit

{ profit = sales price – cost price }


Subset Constraint

Politician Party

1..* 1

1 1

Member of

Party leader of

(subset}


Navigation Expression

• set.Attribute　• set.role• ｓｅｔ ._~role• set{　　boolean　expression　}　• set.[　qualifier　value　}


Template

Array<Car,100>Array

T, n:integer

Color Array

<<bind>><Color,50>


Parameterized class

Dynamic Model

• State Diagram– Describe which states an object can have during its life cycle

• Sequence Diagram– Describe how objects interact and communicate with each other

– The primary focus in sequence diagrams is time

• Collaboration Diagram– Describe how objects interact

– But the focus in a collaboration diagram is space

• Activity Diagram– Describe how objects interact

– But the focus in an activity diagram is work


Object Interaction( Message )

• Synchronous– procedure call or other nested flow of control

• Return– return from a procedure call

• Simple– Flat flow of control

• Asynchronous– Asynchronous flow of control.


Defining behavior of the system by a state diagram

Process Control System

Ochimizu, Higashida, ”Object Modeling”, Addison-Wesley Publishers Japan

What is a State ? on 　　　 init 　　 help ! timeout

time

Frozen Frozen Frozen Frozen Frozen Period 1 Period 2 Period 3 Period 4 Period 5

Not inOperation

Poweron

Monitoring ControllingAlarm

on

on/Action init/Action 　　 help/Action timeout/Action

Success of control/action

Ochimizu, Higashida, ”Object Modeling”,

Addison-Wesley Publishers Japan

State Model

• Represent the behavior of an object by a state transition diagram.

Defining the behavior of philosopher and fork

Each philosopher must use right next fork and left next one not used

right-next

left-next

philosopher forkuse

0..20..1

Ochimizu, Higashida,”Object Modeling”, Addison-Wesley Publishers Japan

Behavior of a Philosopher

thinking

eating

thinking end/

takes forks

eating end/

put down forks


State transition depends on the state of forks both side

State 1 State 2

Event [guard] / action


Detailed behavior of a philosopher

having a forkat left hand

having a forkat right hand

[left-next fork is not used]/take a fork at left hand


[right-next fork is not used]/take a fork at right hand


[forks at both side are not used]/take forks at both hands

/put down forks

waiting

thinking

eating

having two forks



Passive Object and Active Object

• Passive Object– It is activated when it receives a message from other

object ( work when being hit)

• Active Object– It can change its state by itself and send a message to

other object if necessary

• In the case of philosopher– Philosopher’s state of hunger changes autonomously

during thinking and eating.


Simplified behavior

eating

thinking

having a forkat left hand

having a forkat right hand






[forks at both side are not used]/take forks at both hands

/put down forks

Defining the behavior of a fork

not used

used

take ／ takenput down ／ put down


Class Diagram

left-next

philosophername

right handleft hand

take at right handtake at left hand

take at both handput down both

forkname

state of useput

taken

use

right-next

0..20..1


Execution

p2

p3

p4

p5

p1 f1

f2

f3

f4

f5

right-next

right-next

right-next

right-next

right-next

left-next

left-next

left-next

left-next

left-next

use

use



Initial State and Final State

Unpaid Paidpaying

Invoice created


Invoice destroyed

A state diagram for an elevator

On first floor

idle

Moving up

time-outgo down

arrived

go up

go up

Moving down

Moving to first floor

arrivedarrived


State Transition

State 1do ： activity1

State 2event-signature [guard]/action ^send-clause

event-signature: event-name (parameter list)

draw (f: Figure, C: color)

draw()send-clause: destination-expression . Destination-event-name (argument list)

message sent during transition

[timer=time-out] ^ self.go down ( first floor )

destination-expression: object or a series of objects


Guard

Ｊ .Rumbaugh,”Object-Oriented Modeling and Design”, PrenticeHall,199.

East/westmay turn right

time-outtime-out

Time-out [cars in N/S right lanes] North/south

may turn rightNorth/southmay go strait

Time-out [no cars in N/S right lanes]

Time-out [cars in E/W right lanes]

East/westmay go strait

Time-out [no cars in E/W right lanes]

State Generalization

ThirdSecond

Reverse

First

Neutral

push F

push N

push R

push N

stop upshift upshift

downshiftdownshift

Automatic transmission

Forward


Automatic Transition

idleCollecting money

coins in (amount)/add to balance

do: test item and compute change

do: dispense item do: make change

coins in (amount)/set balance

cancel/refund coins

select (item)[item empty] [change<0]

[change>0][change=0]


Sub diagram

Do: move armto correct row

do: move armto correct column

do: push item off shelf

arm ready

arm ready

dispense item



On first floor

idletimer = 0

do: increase timer

Moving updo:moving to floor

[timer=time-out]go down (floor)

arrived

go up (floor)

go up

Moving downdo: moving to floor


arrivedarrived


Events in the state diagram correspond with operations within the class

Displaydo/ display

current time

Set hoursdo/ display

hours

Set minutesdo/ display

minutes

mode~button

mode~button mode~button

inc/minutes:=minutes+1 modulo 60

inc/hours:=hours+1 modulo 24

Digital~watch

mode-button() inc()


Four types of events• Guard (Condition) becomes true.• Receipt of an explicit signal from another

object– The signal itself an object– This type of event is called a message

• Receipt a call on an operation by another object (or by the object itself).– This type of event is also called a message

• Passage of a designated period of time.– This is shown as a time-expression on state transitions.


An event is an object too

<<signal>>Input

{abstract}device: Device

time: Time

<<signal>>Right Mouse

Button

<<signal>>Voice Recognition

commando : String

<<signal>>Keyboard

character:Charup: Boolean

down: Boolean

<<signal>>Mouse

{abstract}up: Boolean

down: BooleanxPos: intyPos: int

<<signal>>Left Mouse

Button

IdleSend

do / send(input)to corresponding

class

input


A state diagram for digital watch

Displaydo/ display

current time

Set hoursdo/ display

hours

Set minutesdo/ display

minutes

mode~button

mode~button mode~button

inc/minutes:=minutes+1 modulo 60

inc/hours:=hours+1 modulo 24


Java program for digital watch (1/2)

public class State{ public final int Display = 1; public final int Set_hours = 2; public final int Set_minutes = 3; public int value;};

public class Watch{ private State state = new State(); private DigitalDisplay LCD = new DigitalDisplay(); public Watch() { state.value = State.Display; LCD.display_time(); }


public void mode_button() { switch ( state.value) { case State.Display: LCD.display_time(): state.value = State.Set_hours; break; case State.Set_hours: LCD.display_hours(): state.value = State.Set_minutes; break; case State.Set_minutes: LCD.display_minutes(): state.value = State.Display; break; } }

public void inc() { switch ( state.value) { case State.Display: : break; case State.Set_hours: LCD.inc_hours(): break; case State.Set_minutes: LCD.inc_minutes(): break; } }}


Java program for digital watch (2/2)

Message passing between two state diagram

On/Play

Play ()

Stop ()

Off() / Stop ()

Off On/Stop

On ()

Off ()

Off On

Off ()

CD Player

Remote ControlOn ()

On () Off ()

Play ()

Play ()

Stop ()

Stop ()


Or-substate and And-substate

Or-substate

And-substate

Running

Running

Forward Backward

Low speed High speed

Forward Backward


History Indicator

• is used to memorize internal state• Support roll-back• If a transition to the indicator fires, the object

resumes the state it had last within that region• Shown as a circle with an H

Ｈ


Sequence Diagram• Sequence diagrams illustrate how objects

interact with each other.• They focus on message sequences, that is, how

messages are sent and received between a number of objects.

• Sequence diagrams have two axes: the vertical axis shows time and the horizontal axis shows a set of objects.

• The Instance form describes a specific scenario in detail

• The Generic form describes all possible alternatives in a scenario, therefore branches, conditions, and loops may be included.:


： Computer： Printer

Server： Printer

The Concepts used In a sequence diagram

Print( ps-file)

Print( ps-file) [no queue] Print( ps-file)

Simple message

Activation

Lifeline

Synchronous message

Object

Guard



Server

Sequence diagram with BranchPrint( ps-file)

Print( ps-file)

： Printer ： Queue

[no queue] Print( ps-file)

[printer busy] Store( file)



Server

Timing Constraint

Print( ps-file)

Print( ps-file)

： Printer

Print( ps-file){ b - a < 5 sec}

{ b’- b < 1 sec }

a

b

b’


C1 ： C D1:D

Iteration

D2:D

send message op2 until ...

op1 ()

op2 ()

op3 ()


： CustomerWindow

D1:D

Creating Object

NewCustomer(Data)

Customer (Data)


： CustomerWindow D1:D

Destroying Object

RemoveCustomer()

DeleteCustomer ()


object name

: class

Recursion

oper()

oper()


Collaboration Diagram

• Collaboration diagrams focus on the interaction and the links between a set of collaborating objects. The sequence diagram focuses on time but the collaboration diagram focuses on space.

[printer free] 1.1: Print(ps-file)

1 ： Print(ps-file)

Print(ps-file)

An example of a collaboration diagram

:Computer

:PrinterServer :Printer


Message Labelpredecessor guard-condition sequence-expression return-value := signature

sequence-number , … /

The predecessor is an expression for synchronization of threads or paths, meaning that the messages connected to specified sequence-number must be performed and handled before the current message is sent.[ integer | name | recurrence] ･ integer a sequence-number specifying the message order 1.2.1 ･ name concurrent thread of control 1.2a 1.2b ･ recurrence * [ iteration-clause] [ condition-clause]

a conditional or iterative exrcution

１ : display() [mode = display] 1.2.3.7: redraw() 2 　＊ [n:=1..z]: prime:=nextPrim(prim)3.1 [ x < 0 ] : foo()3.2 [ x => 0 ] : bar()1.1a, 1.1b/ 1.2: continue()H.E. Eriksson and M. Penker, “UML Toolkit” John Wiley & Sons, Inc.

1 ＊ [ z = 1..n ]: prim:=nextPrim(prim)

CalcPrim (n)

Iteration in a collaboration diagram

:Calculator

:Prim module


Elevator Control

： Button

： Elevator control

： Queue

： Order{new}

： Elevator

Push()

1.1 *[all queues]:len=Length(){broadcast}

1.3: invoke(job)

1.2: Create()

job1:GetElevator(floorid)

2:nextjob=GetJob()

{parameter}job

{local}nextjob


Constraints for link role• Global: specify that the corresponding

instance is visible because it ‘s in a global scope• Local: specify that the corresponding instance

is visible because it’s a local variable in an operation.

• Parameter: specify that the corresponding instance is visible because it’s a parameter in an operation.

• Self: specify that an object can send messages to itself

J. Rumbaugh, I. Jacobson, G. Booch, The Unified Modeling Language Reference Manual, Addison-Wesley


On first floor

idletimer = 0

do: increase timer

Moving updo:moving to floor

[timer=time-out]go down (floor)

arrived

go up (floor)

go up (floor)

Moving downdo: moving to floor


arrivedarrived


Customer Window creation

： CustomerWindow {transient}

： Mainwindow ： Customer{new}

Newcustomer()

3.1: Update(data)

2: Create()

3:Show(customer)

[free memory] 1:Create()

{parameter}


1: Show()

1.1: Create()

3:Show(customer)

1.2 *[while any lines left]: GetResultLine()

1.1.1 *[for all salespersons]: ordersum = GetTotalOrderSum() 1.1.2 *[for all salespersons]: budget = Getbudget()

： SalesPerson

： StatisticsSummary

{new}

： Sales StatisticsWindow

： Order

： Budget Sales

1.1.1.1 *[for all orders]: GetOrderAmount()

1.1.2.1 : GetBudgetAmount()

Summarizing sales results


Exercise

1: ｆ１ ( )

1.1: f2 ( )1.2: f3 ( )

1.1.1: f4 ( ) 1.1.2: f5 ( )

： C3： C2： C1

： C5

： C4

1.1.1.1: f7 ( )

1.1.2.1 : f6 ( )

Answerｆ１( )

f2 ( )

f3 ( )

f7 ( )

f6 ( )

： C1 ： C2 ： C3 ： C4 ： C5

f4 ( )

f5 ( )

call

return

UML Ver.1.3

1 1.1 1.1.1 1.1.1.1 1.1.2 1.1.2.1 1.2

Activity 　 Diagram

• An activity diagram is essentially a flowchart, showing flow of control from activity to activity

Actions and Transitions

Show messageBox

“Printing” onscreen

CustomerWindow.PrintAllCustomer()

Create postscriptfile

Send postscriptfile to printer

RemoveMessageBox


Transition with send-clause

Show messageBox




RemoveMessageBox

^Printer.Print(file)


Transitions are protected by guarded-conditions



RemoveMessageBox

^Printer.Print(file)

[disk full]

Show messageBox

“Disk full” onscreen

Show messageBox

“Printingl” onscreen


Parallel Actions

.Sampler.Run(channel,frequency)

Initiate

Updatingdisplay

Measuring


Swim lanes


Initiate

Updatingdisplay

Measuring

Displayer Sampler


Object Flow


Initiate

Updatingdisplay

Measuring

Displayer Sampler

Measuredvalue


Sending/receiving signals.Sampler.Run(channel,frequency)

ShowMessageBox


RemoveMessageBox

Print file

aPrinter: Printer


Print

Print(file)


Concurrency View

Use-CaseView

ConcurrencyView

LogicalView

DeploymentView

ComponentView


Specific Features of Real-time Systems

• Timeliness is important. The system performs its function within specified time limits.

• Reactive. The system is continuously responding to events from the external environment that “drives” the execution of the system.

• Concurrently executing threads of control, where different parts of the software run in parallel.

• Very high requirements on most of the nonfunctional requirements such as reliability, fault tolerance, and performance.

• Not deterministic


Basic Concepts for real-time system modeling

• time requirement• asynchronous event handling• communication• concurrency

– process, thread

• synchronization


Concurrency　in　Object-Orientation

• Explicit concurrency model– Explicit concurrency model describes concurrency separately from the objects by

defining processes at an early stage of analysis, and then treating processes and objects as separate modeling entities. The system is decomposed into a number of processes, and each process is internally modeled as an object-oriented system to design the internal structure.

• Implicit concurrency model– Implicit concurrency model delay the design of concurrency. The system is modeled

as objects, where in an early analysis, all objects are considered to have their own execution threads; that is, be active objects. Gradually, through architecture and detailed design, the ideal analysis models are mapped onto an implementation with the support of services from the underlying real-time operating system.

• UML can support both – It has better support for the implicit concurrency model. Active classes,

asynchronous communication, and synchronization can be modeled in early phases and gradually be translated into the services and capabilities of the implementation environment.


Active Class and Object

An active class is a one that owns an execution thread and can initiate control activity

Active Class Active Object

<<Active Class>Communication

Supervisor

aninstance :Communication

Supervisor


An active object with its internal structure

:Communication Supervisor

:CommManager

Port1:Communication

Port

Input:MessageBuffert

Output:MessageBuffer


Thread of Control

• Thread: Thread of control– A sequence of control transfer in a program

• Multi Threads– Multiple threads exist together in a program

and they can run concurrently

S. Oaks, H. Wong, “Java Threads”, O’REILLY, 1997.

• public class OurClass {• public void run() {• for(int i = 0; i < 100; i++) {• System.out.println(“Hello”);• }• }• }Import java.applet.Applet;public class OurApplet extends Applet{ public void init() { ourClass oc = new OurClass(); oc.run(); }}

The run() method that writes a string 100 times to standard output is defined in OurClass

This example simply shows a method invocation as shown in the left figure.Execution of Applet thread

Applet executes init()

Applet executes run()

t

Thread using Thread class

Applet thread works by executing run() method in Applet 　


Execute run() method of OurClass concurrently with init() or the other

Applet methods • public class OurClass extends Thread{• public void run() {• for(int i = 0; i < 100; i++) {• System.out.println(“Hello”);• 　　　　　　　｝｝｝

Import java.applet.Applet;public class OurApplet extends Applet{ public void init() { ourClass oc = new OurClass(); oc.start(); }}

Implementation of start() method is in a Thread class or its super class

start() method invokes run() method directly or indirectly.

start() method creates the new thread of control


Methods of the Thread class

• Thread() ： creates a thread object using default values for all option

• void run() : the method that is executed by the newly created thread. It can be considered as a main() of the newly created thread. This method should be over-ridded by the code that is executed by the new thread.

• void start() : creates a new thread and executes run() method that is defined in this thread class

new creation of an instance

sleep sleep

start enqueue it to the thread queue

run public void run() { if (target != null) { target.run(); }}

Default run() method of a Thread object


States of an active object

Ready WaitingRunningSchedule Making Call

TerminateCreate

Running time > 50 msec

Result of call


Run-time environment view of threads

channel

main memory

CPU

pc

channel

register

run() {

}

thread 1

thread 2

createrestore

Running

Readysave

Waiting or Ready

Ready

restore

Waiting or Ready

Running

restoreRunning

Waiting or Ready

t

Applet thread executes the other task

Applet executes init() method

Applet executes internal task thread

Applet executes the start() method

Applet executes its run() method

stop


Execute run() method of OurClass concurrently with init() or the

other Applet methods

• public interface Runnable{• public abstract void run();• }• public class OurClass implements Runnable{• public void run() {• for(int i = 0; i < 100; i++) {• System.out.println(“Hellow”);• } }}


Thread using Runnable Interface

Runnable interface only have a run() method

Import java.applet.Applet;public class OurApplet extends Applet{ public void init() { Runnable ot = new OurClass(); Thread th = new Thread(ot); th.start(); }}

Communication among active objects• Operation call

– An ordinary call of an operation. A caller waits for the operation to finish and return

• Mailboxes/Message queues– This technique allows for asynchronous message

• Shared memory– Two or more active objects can write and read information from/to a block

of memory reserved for communication. The block has to be guarded by some kind of synchronization mechanisms.

• Rendezvous– Specific points in the execution of two threads are defined. The first thread

to reach Its rendezvous point stops and waits for the other thread to reach its corresponding rendezvous point. When both threads are at the rendezvous point, they exchange information and then start to execute concurrently again.

• Remote procedure calls (RPCs)– RPCs handle distribution of the concurrent threads to separate computers in

a network.


Events

• In a real-time system, events are drivers of system activity• An event is something that occurs in the system or in the

environment.• All events that can occur must be defined; furthermore,

the behavior of the system when the event happens must be defined.

• In UML, there are four different categories for events:– A condition (guard) become true– The receipt of an explicit signal object– The receipt of an operation call– A passage of time


Signals

• Signals are defined in UML as “a named event that can be raised

<<signal>>MouseMove

<<signal>>Key

Pressed

<<signal>>ObjectDrop

<<signal>>Perform

Command

<<signal>>Signal

{abstract}

<<signal>>Physical

{abstract}

<<signal>>Logical

{abstract}

<<signal>>Synchronization

{abstract}


Synchronization

• Concurrent processes interact with each other– to exchange data– to share resources, referring variables that show the status of the resource

• It cause the occurrence of time-dependent errors• Synchronization mechanisms are required to avoid errors.

– Mutual exclusion: operation A and operation B should be executed exclusively

– Message buffer: A producer of data can not send data more than the finite capacity of a buffer. A consumer of data can not receive data before it is produced.

– Exchange of timing signals: semaphore invariance– 0 <= r(v) <= s(v) + c(v) <= r(v) ＋ max(integer)– s(v): number of signals sent, r(v): number of signals received, c(v): initial

value of signals, max: maximum countable number of a counter

Problems without synchronization

• The problems that can occur if synchronization is not properly handled– incorrect shared access: use mutual exclusion between

the thread– inefficient resource usage: avoid busy-wait– dead locks: detection, protection, resolution– starvation: thread scheduling


Message Buffer

The position to be written next

The position to be read next

empty

full

synchronization rule

(1) A consumer can not receive the message before the message is sent

0 <= r < s

(2) A producer can not put the new message into the position before the message In the position is read

0 <= s - r < max

The pointer P can not pass the pointer C and the pointer C can not pass the pointer

Ｐ (a producer)Ｃ ( a consumer)

Synchronization Supports in UML

• sequential– The class/operation is intended only for use in a single thread of

control

• guarded– The class/operation will work in the presence of multiple threads

of control. The threads normally have to lock the object/operation before using it, and unlock it afterward.

• synchronized– The class/operation will work in the presence of multiple threads

of control; the class itself handles this. Operation can be declared as synchronized.


Scheduling

• Scheduling is the process of deciding which thread should run next in a situation where several threads are conceivable

• Scheduling is done by the operating system, which allocates the processor to a thread using some predefined algorithm (e.g. round-robin)

• In a complex situation where detailed control is needed of the scheduling, a supervisor thread can be designed.

• In UML, the priority of an active object is most suitably noted as a tagged value of the active class


Implementation of Concurrency and Synchronization in Java

class DemoThread extends Thread{ public void run() { try{ for ( ; ; ) {// Do forever // Synchronous message to System.out object system.out.println(“Hello”); // Asynchronous message placed in Global_mailbox // Needs definition of class Signal and Mailbox // elsewhere. Signal s = new Signal(“Asynch Hello”); Global_mailbox.Put(s); Sleep(10); // Waits for 10 milliSeconds. } } catch ( InterruptedException e) { } } public static void main(String[ ] arg) { // Create an instance of the active class (thread) DemoThread t1 = new DemoThread(); t1.start(); // Start execution // Create another instance of the active class DemoThread t2 = new DemoThread(); t2.start(); // Start execution }}


Basic Mechanisms for Modeling Real-time Systems in UML

- house alarm system -

• Time: time specifications and c ｏｎｓｔｒａｉｎｔｓ are best defined in sequence diagrams

• Concurrency: is described as active classes• Asynchronous event: asynchronous message• Synchronization: c ａｎ be described either as properties of

classes or operations( concurrency properties) or as classes/stereotypes that define mechanism such as a semaphore, monitor, or critical region.

• Distribution: Thread deployed in a distributed system are described in a deployment diagram.


Sensors

<< ＡｃｔｉｖｅＣｌａｓｓ >>Ｓｅｎｓｏｒ

{abstract}＋ id : Address

SelfTest()Activate()

DeActivate()

Photo CellSensor

DevicSpecificConfiguration

parametersSelfTest()Activate()

Deactivate()

HeatSensor



Deactivate()

SoundSensor



Deactivate()

Messages sentfrom a sensordevice is ACKor NAK or an alarm signal


Alarms

<< ＡｃｔｉｖｅＣｌａｓｓ >>Ａｌａｒｍ

＋ id : AddressSelfTest()

Ｔｒｉｇｇｅｒ ()TurnOff()

PhoneAlarm


parametersSelfTest()


LightAlarm




SoundAlarm




Messages sentfrom an alarmdevice is ACK

or NAK


A hierarchy of signal classes

<<signal>>Signal

{abstract}timeSent: Time

sender: ObjectID

<<signal>>Trigger

<<signal>>ACK

<<signal>>NAK

<<signal>>Alarm

<<signal>>Turnoff

<<signal>>General Signals

{abstract}

<<signal>>Sensor Signals

{abstract}

<<signal>>Alarm Signals

{abstract}

<<signal>>Error

<<signal>>Activate

<<signal>>Deactivate

<<signal>>Heartbeat

<<signal>>SelfTest


Class diagram

Supervisor

SoundAlarm

Log

LCD DisplayWrapper

KeyboardHandlerWrapper

System Handler

Cell Handler

Sensor

Alarm

1..*

1..*

<<persistent>>Cell

ConfigurationInformation

<<persistent>>System


1

11

1

1 1

1..*

1..*


Collaboration diagram

： Supervisor

： SoundAlarm

： Log

： System Handler

:Cell Handler

:Photo Cell Sensor

1. Alarm

:PhoneAlarm

:SoundAlarm

2a. Trigger2b. Trigger

2c. Alarm2c.1 Store (Date, Time, Cell, Sensor)

2c.2 Trigger


Sequence diagram

:SystemHandler

:CellHandler

:Sensor :Alarm :Cell


Read Configuration

Config info returned

Activate

Activate

SelfTest

SelfTest

ACK

ACK

ACKACK

A

B

B - A < 5 sec

Repeat for each installed alarm and sensor


State diagramActivation Phase

PerformingAlarm

SelfTest

PerformingSensor

SelfTest

Activatingsensordevice

Creatingdevice list

InitiatingThread loop

SystemActivated

ActivationFailure

/ send ACK

/ send ACK

SelfTest

SelfTest

Activate Command /Send ACK

createList built

success

NAK NAK

NAK

Alarms

Sensors

Cell Handler


Control flows are divided into concurrent threads that run in parallel and later become synchronized again

ActivatingSensors

ActivatingAlarms

InitiatingCell Handler

SystemInactive

SystemActivated

ActivationFailure

“Activate System” command

/ Green light on


The run operation defined for the active Cell Handler class

Waiting forSignal

Documentedin separate

activitydiagrams

Report to System

Alarm(to system handler)

Heartbeat( to system handler)

TriggerAlarm

Order time-out signal from real-time OS

Alarm Activate Deactivate Time-out

ActivateMessageHandling

DeactivateMessageHandling

Time-outMessageHandling

TriggerAlarm A

TriggerAlarm B

TriggerAlarm X

H.E. Eriksson and M. Penker,

“UML Toolkit” John Wiley & Sons, Inc.

The deployment diagram for the house alarm system

<<Thread>>Cell

Handler

<<Thread>>Alarm

<<Thread>>Sensor

<<Thread>>AlarmSystem

Handler

User Panel

Alarm

1 11

1

1..*

1..*

Sensor


The UML definition of architecture

• Architecture is the organizational structure of a system

• An architecture can be recursively decomposed into – parts that interact through interfaces– relationships that connect parts– constraints for assembling parts


Logical Architecture and Physical Architecture

• Logical Architecture– The logical architecture deals with the functionality of the system,

allocating functionality to different parts of the system and specifying in detail how the solution work.

– In UML, the diagram used to describe the logical architecture are usecase, class, state, activity, collaboration, and sequence.

• Physical Architecture– The physical architecture deals with a detailed description of the system,

in terms of the hardware and software that the system contains. It reveals the structure of the hardware, including different nodes and how these nodes are connected to each other. It also illustrates the physical structure and dependencies of the code modules that implement the concepts defined in the logical architecture; and distribution of the run-time software in terms of processes, programs, and other components.

– In UML, the diagram used to describe the physical architecture are component and deployment


Allocating Components to Nodes• Class and collaborations as defined in the logical design are allocated to

components in which they are implemented. The allocation is driven by the programming language used. Java implements a class in just one file.

• The processes are allocated to the components in which they execute.• Components are allocated to nodes.• A component instance executes on at least one node instance.• There are a number of aspects to consider when allocating components to

nodes.– Resource Usage of the hardware– Geographical location– Access to devices– Security– Performance– Extensibility and portability


Deployment View

Use-CaseView

ConcurrencyView

LogicalView

DeploymentView

ComponentView


UML notations

Package: Subsystem, Framework

Interface

realization (simple form)

realization (expanded form)


Interface

Class A Class B

Storable

Runnable

<<interface>>Runnable{abstract}

run(){ abstract}

<<interface>>Storeble

{abstract}

load(){ abstract}save(){ abstract}


Java Implementation

interface Storable{ public void save(); public void load();};

public class Person implements Storable{ public void save(); { /* Implementation of save operation for Person */ } public void save(); { /* Implementation of load operation for Person */ }};H.E. Eriksson and M. Penker, “UML Toolkit” John Wiley & Sons, Inc.

Package

A pakage is a grouping mechnism, whereby all kinds of model elements can be linked

Subsystem A

Subsystem B

Subsystem D

Subsystem C

Subsystem E


UML notation

NodeA physical element that exists at run time and that represents a computational resource, generally having at least some memory and, often times, processing capability

ATMData

Server


Node

Bill’s Machine:Dell

Pentium 466MMX

node type an instance

DellPentium 466

MMX

<<Printer>>HP LaserJet

5MP

<<CarController>>SAAB 9-5Navigator

<<Router>>Cisco Router

X2000

Device nodes and possible stereotype


Communication Association between nodes

ClientB:Compaq Pro PC

ClientA:Compaq Pro PC

ApplicationServer:

Silicon GraphicsO2

DatabaseServer:VAX

“TCP/IP”

“TCP/IP”

<<DecNet>>


Component Allocation

<<library>>Transaction

ClientLibrary

ＵＮＩＸTransaction

ServerProgram

SiliconGraphics

O2

<<support>>

Bill’s Machine: Dell Pentium MMX PC

Executable component instances may be contained within node instance symbols, showing that they reside and execute on the node instance

A node type supporting a run-time component type, and a run-time component instance executing in a node instance

ClientProgram


Use the services of another component

Allocation of Object

Microwave Oven System: Microwave Oven Controller

A passive object ( of ThermometerController ) within an active process object ( of active class SuperVisor ) that lives within a component instance ( of type guard.exe ), which is allocated to the node Microwave Oven System ( of type Microwave Oven Controller ).

guard.exe

<<process>> SuperVisor

ThermometerController


Object AllocationObjects are allocated to nodes. The transobj object that originally exists in the Main Server node can be distributed to the Dell PC node shown with the stereotype <<becomes>>

Main Server: Quad Pentium PCBill’s Machine:

Dell Pentium MMX PC Transaction Server Program

transobj dlbobj callobj

t1:updatethread

Client Program

transobj

<<become>>


Complex Modeling

Client PC

NetDrv

ApplClient

Window95

Admin PC

AdminPgm

BackupStation

Server

1backupMedium1

1..* 1..2

connected To


Component View

Use-CaseView

ConcurrencyView

LogicalView

DeploymentView

ComponentView


UML notation

ComponentA component is a physical and replaceable part of a system that conforms to and provides the realization of a set of Interfaces. Graphically, a component is rendered as a rectangle with tabs.

<<executable>>

client.exe


An example of a component diagram

WindowHandler

(whnd.obj)

MainClass

(main.cpp)

MainClass

(main.obj)

Graphiclib

(graphic.dll)

CommHandler

(comhnd.obj) ClientProgram

(client.exe)

WindowHandler

(whnd.cpp)

CommHandler

(comhnd.cpp)


Three kinds of components

• Source component

• Binary component

• Executable component


Interfaces and Dependencies

Runnableupdatethread.java

display.java


Compile-time Component

<<file>>animlogo.java

<<file>>animator.java

<<document>>animlogo.doc

<<document>>animator.doc

<<file>> a file containing source code

<<page>> a Web page

<<document>> a document

<<page>>home.html


Run-time Components

<<library>>graphics.dII

<<library>>dbhandler.dII

<<library>>commhandler.dII

<<application>>umlviewer.exe


Use of UML• Information system

– Handle large amounts of data with complex relationships, which are stored in relational or object databases

• Technical system– Handle control technical equipment such as telecommunications, military systems,

or industrial processes. They must handle the special interfaces of the equipment and have less standard software than Information system. The are often real-time system.

• Embedded real-time systems– Execute on simple hardware embedded in some other equipment such as a mobile

phone, car, household appliance, etc.• Distributed systems

– Distributed on a number of machines where data Is transferred easily from one machine to another. They require synchronized communication mechanisms to ensure data integrity and are often built upon object mechanisms such as CORBA, COM/DCOM, or Java Beans/RMI

• System software– Define the technical infrastructure that other software uses. Operating system.

Databases.• Business system

– Describe the goals, the resources (human, computers), the rules (laws, business strategies, policies), and the actual work in the business


Documents

Details of UML and Unified Process Koichiro OCHIMIZU School of Information Science JAIST