UML SEQUENCE DIAGRAM

Concepts & Notations

Acknowledgements The material in this tutorial is

based in part on:

The Unified Modeling Language Reference Manual, 2nd edition, by James Rumbaugh, Ivar Jacobson, and Grady Booch

UML Sequence Diagram

Interaction View Interaction Diagram Sequence Diagram Examples

Interaction View Objects interact to implement behavior

Two ways to describe interactionfocus on individual objects (state machine)focus on interactions of a collection of

cooperating objects (interaction view)

Provides a more holistic view of the behavior of a set of objects

Interaction Diagram Collaboration Diagram

Emphasizes structural relations between objects

Sequence DiagramIllustrates how objects interacts with each

otherEmphasizes time ordering of messages

Sequence Diagram

member:LibraryMember book:Book :Book

Copy

borrow(book)ok = mayBorrow()

[ok] borrow(member)setTaken(member)

Sequence Diagram

member:LibraryMember book:Book :Book

Copy

borrow(book)ok = mayBorrow()

[ok] borrow(member)setTaken(member)

X-Axis (roles)

Y-Axis (tim

e)

Sequence Diagram

member:LibraryMember book:Book :Book

Copy

borrow(book)ok = mayBorrow()

[ok] borrow(member)setTaken(member)

X-Axis (roles)

Y-Axis (tim

e)

head symbol

life line

Sequence Diagram

member:LibraryMember book:Book :Book

Copy

borrow(book)ok = mayBorrow()

[ok] borrow(member)setTaken(member)

X-Axis (roles)

Y-Axis (tim

e)

head symbol

life line

activation double line

Object Naming

syntax[instance Name]:[class Name]

Life linerepresents the object’s life during the

interaction

bDay:Date

Object Active Object

holds the root of a stack executionshas its own thread of control

Passive Objectobjects that are called by an active objectreceive control only when called

Object

pull

pull

: Queueactor1 : … actor2 : …

active object active objectpassive object

Message An interaction between two objects

operation callsignalingRPC

An arrow between the life lines of two objects

Labeled withnameargumentscontrol information

Message

pull

pull

: Queueactor1 : … actor2 : …

message

message

Synchronous Message The routine that handles the message is

completed before the caller resumes execution

:A :B

doYouUnderstand()Caller

Blocked

return (optional

)

yes

synchronous message

Creation Message An object may create another object via

a create() message

old:A

create() :B

Preferredcreate

message

Destruction Message An object may destroy another object

via a destroy() message

old:A new:B

destroy()

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Examples

print(doc,client)Client

:PrintServer :Queue :PrinterProxy

enqueue(job)

status

job=dequeue()

[job]print(job.doc)

[job] done(status)

Repeated forever with 1 min interludes

Review Time on y-axis, roles on x-axis Activation bars represent executions of

procedures Active objects have bars Solid arrowheads: synchronous Stick arrowheads: asynchronous Dashed message lines: return

:PrintServer