c:\documents and settings\student\desktop\swaroop uml

$: C:\documents and settings\student\desktop\swaroop uml$
Short Introduction into UML

Use Cases, State Charts and Activity Charts

2

Behavioral Elements

Model Management

Foundation

Use Cases State Machines Activity GraphsCollaborations

Common Behavior

UML Overview

3

Use Case Modeling

What is use case modeling? Core concepts Diagram tour When to model use cases Modeling tips Example: Online HR System

4

What is use case modeling?

use case model: a view of a system that emphasizes the behavior as it appears to outside users. A use case model partitions system functionality into transactions (‘use cases’) that are meaningful to users (‘actors’).

5

Use Case Modeling: Core Elements

Construct Description Syntax

use case A sequence of actions, including variants, that a system (or other entity) can perform, interacting with actors of the system.

actor A coherent set of roles that users of use cases play when interacting with these use cases.

system boundary

Represents the boundary between the physical system and the actors who interact with the physical system.

UseCaseNam e

ActorNam e

6


association The participation of an actor in a use case. i.e., instance of an actor and instances of a use case communicate with each other.

generalization A taxonomic relationship between a more general use case and a more specific use case.

extend A relationship from an extension use case to a base use case, specifying how the behavior for the extension use case can be inserted into the behavior defined for the base use case.

Use Case Modeling: Core Relationships

<<extend>>

7


include An relationship from a base use caseto an inclusion use case, specifyinghow the behavior for the inclusion usecase is inserted into the behaviordefined for the base use case.

Use Case Modeling: Core Relationships (cont’d)

<<include>>

8

Shows use cases, actor and their relationships

Use case internals can be specified by text and/or interaction diagrams

Kinds use case diagram use case description

Use Case Diagram Tour

9

Fig. 3-53, UML Notation Guide

Customer

Supervisor

SalespersonPlace

Establishcredit

Check

Telephone Catalog

F ill orde rs

Shipping Clerk

status

order

Use Case Diagram

10


Use Case Relationships

additional requests :

OrderProduct

SupplyArrange

«include»«include»«include»

RequestCatalog

«extend»Extension points

PaymentCustomer Data

after creation of the order

Place Order

1 * the salesperson asks forthe catalog

11


Actor Relationships

EstablishCredit

PlaceOrder

Salesperson

Supervisor

1 *

1 *

12

Use Case Description: Change Flight

Actors: traveler, client account db, airline reservation systemPreconditions:

Traveler has logged on to the system and selected ‘change flight itinerary’ option

Basic course System retrieves traveler’s account and flight itinerary from client account database System asks traveler to select itinerary segment she wants to change; traveler selects itinerary segment. System asks traveler for new departure and destination information; traveler provides information. If flights are available then … System displays transaction summary.

Alternative courses If no flights are available then …

13

When to model use cases Model user requirements with use

cases. Model test scenarios with use cases. If you are using a use-case driven

method start with use cases and derive your

structural and behavioral models from it.

If you are not using a use-case driven method make sure that your use cases are

consistent with your structural and behavioral models.

14

Use Case Modeling Tips

Make sure that each use case describes a significant chunk of system usage that is understandable by both domain experts and programmers

When defining use cases in text, use nouns and verbs accurately and consistently to help derive objects and messages for interaction diagrams

Factor out common usages that are required by multiple use cases

If the usage is required use <<include>> If the base use case is complete and the usage may be

optional, consider use <<extend>> A use case diagram should

contain only use cases at the same level of abstraction include only actors who are required

Large numbers of use cases should be organized into packages

15

Example: Online HR System

Online HR System

LocateEm ployees

UpdateEm ployee

Profile

Update Benefits

Access TravelSystem

Access PayRecords

Em ployee

M anager

Healthcare Plan System

{if currentMonth = Oct.}

{readOnly}

Insurance P lan System

16

Online HR System: Use Case Relationships

Update M edicalP lan

Update DentalP lan

Update Benefits______________Extension pointsbenefit options:

after required enrollm ents

UpdateInsurance P lan

Em ployee

<<include>> <<include>> <<include>>

ElectReim bursem entfor Healthcare

Elect StockPurchase

<<extend>>em ployee requestsstock purchase option

<<extend>>em ployee requestsreim bursem ent option

extensioncondition

extension pointname andlocation

17

Online HR System: Update Benefits Use

Case

Actors: employee, employee account db, healthcare plan system, insurance plan systemPreconditions:

Employee has logged on to the system and selected ‘update benefits’ option

Basic course System retrieves employee account from employee account db System asks employee to select medical plan type; include Update Medical Plan. System asks employee to select dental plan type; include Update Dental Plan. …

Alternative courses If health plan is not available in the employee’s area the employee is informed and asked to select another plan...

18

State Machines Overview

Basic State Machine Concepts Statecharts and Objects Advanced Modeling Concepts Wrap Up

19

ONONONON

Automata

A machine whose output behavior is not only a direct consequence of the current input, but of some past history of its inputs

Characterized by an internal state which represents this past experience

ONONONONONONONON ONONONON

OFFOFFOFFOFF

20

off

on

State Machine (Automaton) Diagram

Graphical rendering of automata behavior

Lamp OnLamp OnLamp OnLamp On

Lamp OffLamp OffLamp OffLamp Off

off

on

21

Outputs and Actions

As the automaton changes state it can generate outputs:

on

off

Lamp OnLamp Onprint(”on”)print(”on”)Lamp OnLamp Onprint(”on”)print(”on”)

Lamp Lamp OffOff

Lamp Lamp OffOff

off

on

Moore automaton

on

off

Lamp Lamp OnOn

Lamp Lamp OnOn

Lamp Lamp OffOff

Lamp Lamp OffOff

off

on/print(”on”)print(”on”)

Mealy automaton

22

Extended State Machines

Addition of variables (“extended state”)

off

on

Lamp OnLamp OnLamp OnLamp On

Lamp OffLamp OffLamp OffLamp Off

off

on/ctr := ctr + 1

ctr : Integerctr : Integerctr : Integerctr : Integer

23

A Bit of Theory

An extended (Mealy) state machine is defined by: a set of input signals (input alphabet) a set of output signals (output alphabet) a set of states a set of transitions

triggering signal action

a set of extended state variables an initial state designation a set of final states (if terminating

automaton)

24

top

Basic UML Statechart Diagram

ReadyReadyReadyReady

stop

/ctr := 0stop

StateStateStateState

TriggerTriggerTriggerTrigger

ActionActionActionAction

Initial Initial pseudostatepseudostate

Initial Initial pseudostatepseudostate

TransitionTransitionTransitionTransition

Final Final statestateFinal Final statestate

DoneDoneDoneDone

““top” statetop” state““top” statetop” state

25

What Kind of Behavior?

In general, state machines are suitable for describing event-driven, discrete behavior inappropriate for modeling continuous

behavior

timetime

thresholdthreshold

26

Event-Driven Behavior

Event = a type of observable occurrence interactions:

synchronous object operation invocation (call event) asynchronous signal reception (signal event)

occurrence of time instants (time event) interval expiry calendar/clock time

change in value of some entity (change event) Event Instance = an instance of an event

(type) occurs at a particular time instant and has no

duration

27

The Behavior of What?

In principle, anything that manifests event-driven behavior NB: there is no support currently in

UML for modeling continuous behavior In practice:

the behavior of individual objects object interactions

The dynamic semantics of UML state machines are currently mainly specified for the case of active objects

28

Basic State Machine Concepts

Statecharts and Objects

Advanced Modeling Concepts

Wrap Up

29

Object Behavior - General Model

Simple server model:

HandleHandleRequestRequest


InitializeInitializeObjectObject


TerminateTerminateObjectObject


Wait forWait forRequestRequest


void:offHook (); {busy = true; obj.reqDialtone(); … };

Handling depends on Handling depends on specific request typespecific request type

Handling depends on Handling depends on specific request typespecific request type

30

Object Behavior and State Machines

Direct mapping:

HandleHandleEventEvent



Wait forWait forEventEvent

on

off

Lamp Lamp OnOn

Lamp Lamp OnOn

Lamp Lamp OffOff

Lamp Lamp OffOff

off

on/print(”on”)

stop

31

















Object and Threads

•Passive objects: depend on external power (thread of execution)•Active objects: self-powered (own thread of execution)

32

Passive Objects: Dynamic Semantics

•Encapsulation does not protect the object from concurrency conflicts!•Explicit synchronization is still required









33

anActiveObjectanActiveObject

#currentEvent : Event#currentEvent : Event

+ start ( )+ start ( )+ poll ( )+ poll ( )+ stop ( )+ stop ( )

Active Objects and State Machines

Objects that encapsulate own thread of execution

created

ready

start/^master.ready()

poll/^master.ack()

stop/

poll/defer

ready

created

start start/^master.ready() ready

34

Active Objects: Dynamic Semantics

Run-to-completion model: •serialized event handling •eliminates internal concurrency•minimal context switching overhead

ActiveObject:

35

Active1Active1Active1Active1 Active2Active2Active2Active2

The Run-to-Completion Model

A high priority event for (another) active object will preempt an active object that is handling a low-priority event

hi

hi

lo

36




Wrap Up

37

State Entry and Exit Actions

A dynamic assertion mechanism

LampOnLampOnLampOnLampOn

entry/lamp.on();

exit/lamp.off();

e1e1

e2e2

38

Resulting action sequence:Resulting action sequence:printf(“exiting”);printf(“exiting”);printf(“to off”);printf(“to off”);lamp.off();lamp.off();

Resulting action sequence:Resulting action sequence:printf(“exiting”);printf(“exiting”);printf(“to off”);printf(“to off”);lamp.off();lamp.off();

Order of Actions: Simple Case

Exit actions prefix transition actions

Entry action postfix transition actions

printf(“exiting”);printf(“exiting”);printf(“needless”);printf(“needless”);lamp.off();lamp.off();

printf(“exiting”);printf(“exiting”);printf(“needless”);printf(“needless”);lamp.off();lamp.off();

off/printf(“needless”);off/printf(“needless”);

off/printf(“to off”);off/printf(“to off”);LampOffLampOffLampOffLampOff

entry/lamp.off();entry/lamp.off();

exit/printf(“exiting”);exit/printf(“exiting”);


entry/lamp.on();entry/lamp.on();


39

Internal Transitions

Self-transitions that bypass entry and exit actions

LampOffLampOffLampOffLampOff

entry/lamp.off();entry/lamp.off();


off/null;

Internal transitionInternal transitiontriggered by triggered by an “off” eventan “off” event

Internal transitionInternal transitiontriggered by triggered by an “off” eventan “off” event

40

ErrorErrorErrorError

entry/printf(“error!”)entry/printf(“error!”)

State (“Do”) Activities

Forks a concurrent thread that executes until: the action completes or the state is exited through an

outgoing transition

do/while (true) alarm.ring();

““do” activitydo” activity““do” activitydo” activity

41

Guards

Conditional execution of transitions guards (Boolean predicates) must be side-effect free

SellingSellingSellingSelling

UnhappyUnhappyUnhappyUnhappy

HappyHappyHappyHappy

bid bid [(value >= 100) & (value < 200)] /sell /sell

bid bid [value >= 200] /sell /sell

bid bid [value < 100] /reject /reject

42

Static Conditional Branching

Merely a graphical shortcut for convenient rendering of decision trees

[(value >= 100) & (value < 200)] /sell /sell

[value >= 200] /sell /sell

[value < 100] /reject /reject




bidbid

43

bid /gain := calculatePotentialGain(value)




Dynamic Conditional Branching

Choice pseudostate: guards are evaluated at the instant when the decision point is reached

[(gain >= 100) & (gain < 200)] /sell /sell

[gain >= 200] /sell /sell

[gain < 100] /reject /reject

DynamicDynamicchoicepointchoicepointDynamicDynamic

choicepointchoicepoint

44

Hierarchical State Machines

Graduated attack on complexity states decomposed into state

machinesLampFlashingLampFlashingLampFlashingLampFlashingflash/flash/

1sec/1sec/1sec/1sec/

FlashOffFlashOffFlashOffFlashOff

entry/lamp.off()entry/lamp.off()

FlashOnFlashOnFlashOnFlashOn

entry/lamp.on()entry/lamp.on()off/off/




entry/lamp.on()entry/lamp.on()

on/on/

on/on/on/on/

45

“Stub” Notation

Notational shortcut: no semantic significance

LampFlashingLampFlashingLampFlashingLampFlashingflash/flash/

on/on/

FlashOnFlashOn

FlashOffFlashOff

off/off/





on/on/ on/on/

46

LampFlashingLampFlashingLampFlashingLampFlashing

1sec/1sec/1sec/1sec/




entry/lamp.on()entry/lamp.on()off/off/





on/on/

Group Transitions

Higher-level transitions

flash/flash/

on/on/

Default transition toDefault transition tothe initial pseudostatethe initial pseudostateDefault transition toDefault transition to

the initial pseudostatethe initial pseudostate

Group transitionGroup transitionGroup transitionGroup transition

47

Completion Transitions

Triggered by a completion event generated automatically when an

immediately nested state machine terminates

CommittingCommittingCommittingCommitting

Phase1Phase1Phase1Phase1

Phase2Phase2Phase2Phase2CommitDoneCommitDoneCommitDoneCommitDone

completion completion transition (no trigger)transition (no trigger)

completion completion transition (no trigger)transition (no trigger)

48

LampFlashingLampFlashingLampFlashingLampFlashing

off/off/



Triggering Rules

Two or more transitions may have the same event trigger innermost transition takes precedence event is discarded whether or not it triggers

a transition

on/

on/

49

Deferred Events

Events can be retained if they do not trigger a transition

off/off/



on/on/



off/deferoff/defer

Deferred eventDeferred eventDeferred eventDeferred event

50

Order of Actions: Complex Case

Same approach as for the simple case

S1S1exit/exS1exit/exS1




S2S2entry/enS2entry/enS2




initS2initS2E/actEE/actE

Actions execution sequence:

exS11 exS1 actE enS2 initS2 enS21

51

suspend/suspend/

History

Return to a previously visited hierarchical state deep and shallow history options

DiagnosingDiagnosingDiagnosingDiagnosing

Diagnostic1Diagnostic1Diagnostic1Diagnostic1

Step11Step11Step11Step11


Diagnostic2Diagnostic2Diagnostic2Diagnostic2


Step22Step22Step22Step22resume/resume/H*H*H*H*

52

Orthogonality

Multiple simultaneous perspectives on the same entity

ChildChild

AdultAdult

RetireeRetiree

ageage

PoorPoor

RichRich

financialStatusfinancialStatus

53

Orthogonal Regions

Combine multiple simultaneous descriptions

ChildChild

AdultAdult

RetireeRetiree

ageage

PoorPoor

RichRich


PoorPoor

RichRich


ChildChild

AdultAdult

RetireeRetiree

ageage

54

OutlawOutlawOutlawOutlaw

LawAbidingLawAbidingLawAbidingLawAbiding PoorPoorPoorPoor

RichRichRichRich

financialStatusfinancialStatuslegalStatuslegalStatus

Orthogonal Regions - Semantics

All mutually orthogonal regions detect the same events and respond to them “simultaneously” usually reduces to interleaving of some kind

robBank/robBank/ robBank/robBank/

55

Catch22Catch22Catch22Catch22

sanityStatussanityStatus flightStatusflightStatus

Interactions Between Regions

Typically through shared variables or awareness of other regions’ state changes

(flying)/(flying)/

CrazyCrazyentry/sane := false;entry/sane := false;

CrazyCrazyentry/sane := false;entry/sane := false;

SaneSaneentry/sane := true;entry/sane := true;

SaneSaneentry/sane := true;entry/sane := true;

requestrequestGrounding/Grounding/

FlyingFlyingentry/flying := true;entry/flying := true;

FlyingFlyingentry/flying := true;entry/flying := true;

GroundedGroundedentry/flying := false;entry/flying := false;

GroundedGroundedentry/flying := false;entry/flying := false;

(sane)/(sane)/

(~sane)/(~sane)/

sane : Booleansane : Booleansane : Booleansane : Boolean

flying : Booleanflying : Booleanflying : Booleanflying : Boolean

56

Transition Forks and Joins

For transitions into/out of orthogonal regions:

StaffStaffMemberMember

StaffStaffMemberMember

employeeemployee

ChildChildChildChild AdultAdultAdultAdult RetireeRetireeRetireeRetiree

ageage

ManagerManagerManagerManager

57

Common Misuse of Orthogonality

Using regions to model independent objects

ChildChild

AdultAdult

RetireeRetiree

ChildChild

AdultAdult

RetireeRetiree

Person1Person1 Person2Person2

Person1Person1 Person2Person2

58




Wrap Up

59

Wrap Up: Statecharts

UML uses an object-oriented variant of Harel’s statecharts adjusted to software modeling needs

Used to model event-driven (reactive) behavior well-suited to the server model inherent in

the object paradigm Primary use for modeling the behavior

of active event-driven objects systems modeled as networks of

collaborating state machines run-to-completion paradigm significantly

simplifies concurrency management

60

Wrap Up: Statecharts (cont’d)

Includes a number of sophisticated features that realize common state-machine usage patterns: entry/exit actions state activities dynamic and static conditional branching

Also, provides hierarchical modeling for dealing with very complex systems hierarchical states hierarchical transitions orthogonality

61

Activity Diagram Applications

Intended for applications that need control flow or object/data flow models …

... rather than event-driven models like state machines.

For example: business process modeling and workflow.

The difference in the three models is how step in a process is initiated, especially with respect to how the step gets its inputs.

62

Activity Diagrams Based on State Machines

Currently activity graphs are modeled as a kind of state machine.

Modeler doesn't normally need to be aware of this sleight-of-hand ...

... but will notice that "state" is used in the element names.

Activity graphs will become independent of state machines in UML 2.0.

63

Just like their state machine counterparts (simple state and submachine state) except that ...

... transitions coming out of them are taken when the step is finished, rather than being triggered by a external event, ...

... and they support dynamic concurrency.

Kinds of Steps in Activity Diagrams

Action Action (State)

Subactivity Subactivity (State)

64

Action (State)

An action is used for anything that does not directly start another activity graph, like invoking an operation on an object, or running a user-specified action.

However, an action can invoke an operation that has another activity graph as a method (possible polymorphism).

Action

65

Subactivity (State)

A subactivity (state) starts another activity graph without using an operation.

Used for functional decomposition, non-polymorphic applications, like many workflow systems.

The invoked activity graph can be used by many subactivity states.

Subactivity

66

Example

POEmployee.sortMail Deliver Mail

POEmployee

sortMail() Check OutTruck

Put MailIn Boxes

Deliver Mail

67

POEmployee

sortMail()

Activity Graph as Method

Application is completely OO when all action states invoke operations

All activity graphs are methods for operations.

POEmployee.sortMail POEmployee.deliverMail

deliverMail()«realize»

Check OutTruck

Put MailIn Boxes

PO Employee Deliver Mail Method

68

Dynamic concurrency

Applies to actions and subactivities. Not inherited from state machines. Invokes an action or subactivity any number of times in

parallel, as determined by an expression evaluated at runtime. Expression also determines arguments.

Upper right-hand corner shows a multiplicity restricting the number of parallel invocations.

Outgoing transition triggered when all invocations are done.

Currently no standard notation for concurrency expression or how arguments are accessed by actions. Attach a note as workaround for expression. Issue for UML 2.0.

Action/Subactivity *

69

Object Flow (State)

A special sort of step (state) that represents the availability of a particular kind of object, perhaps in a particular state.

No action or subactivity is invoked and control passes immediately to the next step (state).

Places constraints on input and output parameters of steps before and after it.

Class[State]

70

Object Flow (State)

Take Order must have an output parameter giving an order, or one of its subtypes.

Fill Order must have an input parameter taking an order, or one of its supertypes.

Dashed lines used with object flow have the same semantics as any other state transition.

Order[Taken]

Take Order Fill Order

71

Coordinating Steps

Initial state

Final state

Fork and join

Inherited from state machines

72

Decision point and merge ( ) are inherited from state machines.

For modeling conventional flow chart decisions.

Coordinating Steps

CalculateCost

ChargeAccount

GetAuthorization

[cost < $50]

[cost >= $50]

73

Synch state ( ) is inherited from state machines but used mostly in activity graphs.

Provides communication capability between parallel processes.

Coordinating Steps

State machinenotation

InspectInstall

Foundation

BuildFrame

InstallElectricity

in Foundation

PutOn

Roof

InstallElectricityIn Frame

InstallElectricityOutside

InstallWalls

* *

74

Convenience Features (Synch State)

Forks and joins do not require composite states.

Synch states may be omitted for the common case (unlimited bound and one incoming and outgoing transition).

BuildFrame

InstallFoundation

InstallElectricity

in Foundation

PutOn

Roof

InstallElectricityIn Frame

InstallElectricityOutside

InstallWalls

Inspect

Activity diagramnotation

75

Convenience Features (Synch State)

Object flow states can be synch states

O bj[S2]

A11 A12 A13

A21 A22 A23

76

Convenience Features

Fork transitions can have guards.

RegisterBug

EvaluateImpact

FixBug

RevisePlan

ReleaseFix

TestFix

[ priority = 1]

RegisterBug

EvaluateImpact

FixBug

RevisePlan

ReleaseFix

TestFix

[ priority = 1]

[else]

Instead of doing this:

77


Partitions are a grouping mechanism. Swimlanes are the notation for partitions. They do not provide domain-specific

semantics. Tools can generate swimlane presentation

from domain-specific information without partitions.

RegisterBug

EvaluateImpact

FixBug

RevisePlan

ReleaseFix

TestFix

[ priority = 1]

Management

Support

Engineering

78


Signal send icon

Signal

CoffeePot

Wake Up

Get Cups

Turn on Coffee Pot

Coffee Done

Drink Coffee

Signal

… translates to a transition with a send action.

Signal receipt icon

… translates to a wait state (a state with no action and a signal trigger event).

79

Case

Stu

dy

partition

Submission Team Task Force Revision Task Force

Issue RFP

Evaluate initialsubmissions

Submitspecification

draft

Collaborate withcompetitivesubmitters

Developtechnology

specification

action state

RFP[issued]

[optional]

control flow

Finalizespecification

Specification[initial

proposal]

input value

Begin

object flow

initial state

join of control

conditionalfork

fork of control

Specification[final

proposal]

Ad

ap

ted

fro

mK

ob

ryn

, “U

ML

20

01

”C

om

mu

nic

atio

ns

of

the

AC

MO

cto

be

r 1

99

9

80

Case

Stu

dy

Ad

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fro

mK

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, “U

ML

20

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”C

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of

the

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be

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99

9

Evaluate initialsubmissions

Evaluate finalsubmissions

Vote torecommend

Enhancespecification

Implementspecification

Revisespecification

Finalizespecification

Specification[final

proposal]

Specification[adopted]

Recommendrevision

Specification[revised]

[NO][YES]

[else] [Enhanced]

decision

final state

guard

Collaborate withcompetitivesubmitters

81

When to Use Activity Diagrams

Use activity diagrams when the behavior you are modeling ... does not depend much on external

events. mostly has steps that run to completion,

rather than being interrupted by events. requires object/data flow between steps. is being constructed at a stage when

you are more concerned with which activities happen, rather than which objects are responsible for them (except partitions possibly).

82

Activity Diagram Modeling Tips

Control flow and object flow are not separate. Both are modeled with state transitions.

Dashed object flow lines are also control flow.

You can mix state machine and control/object flow constructs on the same diagram (though you probably do not want to).

83


RequestReturn

Get ReturnNumber

Ship Item

Item[returned]

ReceiveItem

RestockItem

CreditAccount

Item[available]

Customer Telesales WarehouseAccountingFrom UML User Guide:

84

Act

ivit

y M

odelin

g T

ips

RequestReturn

Get ReturnNumber

Ship Item

Item[returned]

ReceiveItem

RestockItem

CreditAccount Item

[available]

Customer Telesales WarehouseAccounting

85

Activity Diagram Modeling Tips Activity diagrams inherit from state machines

the requirement for well-structured nesting of composite states.

This means you should either model as if composite states were there by matching all forks/decisions with a correspond join/merges …

… or check that the diagram can be translated to one that is well-nested.

This insures that diagram is executable under state machine semantics.

86


Well-nested:

87

Not well-nested:


Apply structured coding principles. (Be careful with goto’s!)

88


Can be translated to well-nesteddiagram on earlier slide:

89

Wrap Up: Activity Diagrams

Use Activity Diagrams for applications that are primarily control and data-driven, like business modeling …

… rather than event-driven applications like embedded systems.

Activity diagrams are a kind of state machine until UML 2.0 …

… so control and object/data flow do not have separate semantics.

UML 1.3 has new features for business modeling that increase power and convenience. Check it out and give feedback!

c:\documents and settings\student\desktop\swaroop uml

Education

use case diagram

use case relationships

base use case

uml use cases

transactions use cases

multiple use cases

usecase driven method

large numbers of use