UML and WSDL
for JISC e-Learning Projects
UML Details
Richard Hopkins
rph@nesc.ac.uk
NeSC Training Team Member
Goals
Goals –
To understand sufficient details of UML to be
able to use it as documentation for


user requirement
System (service) definition
To have an appreciation of other parts of
UML
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Overview
Overview –diagram types
Use Case –
Class Collaboration –
Object –
Sequence –
State –
Appreciation onlyActivity
Packages
Deployment
Summary
Exercise
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more detail
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Warning
Exactly what is and what is not UML?
Difficult question
No Full implementation to test a question
Different Author give conflicting views
The Formal Definition is obscure
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Simple Use Cases
Return Copy
BookBorrower
Notify lost
Copy
Use case diagram showing our first
attempt at two of the functionalities
Further consideration leads to -
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Use Case Relationships
Return Copy
Clerk
Book
Returner
<<extend>>
Notify lost
Copy
Return Overdue
<<include>> Copy
<<extend>>
– a variation of
the indicated base
case
<<include>>
Pay fine
<<extend>>
Defer fine
Note – Participant
Inheritance
BookReturner & CLerk
implicitly involved in
Return Overdue Copy
<<include>>
– allows common
sub-structure to
be factored out.
Pay fine by
credit card
Pay Fine needs to be
specific about
participants
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show clerk –
sometimes involved,
sometimes not
system might record
which clerk –
affects class diag.
Generalisation /Specialisation
(same arrow type as in class diag.)
– a special case of.
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Use Case Relationships
Specialisation vs Extension
Return Copy
Distinction not clear-cut
(some say UML should not have both)
<<extend>>
Return Overdue
<<include>> Copy
For extension base case can document the
conditions for the extension case
(“extension point”)
One possible decider -
Pay fine
<<extend>>
Defer fine
Generalisation is when user unilaterally
chooses a variant
Pay fine by
credit card
Extension is when system detects the
condition, or needs to check whether it is OK
– testing internal system state
.
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Use Case - Variants
Library
Book
Reserver
<<actor>
>Book
Reserver
Reserve book
personally
Clerk
Reserve
Book
electronically
Reserve
Book
Authenticate
User
Show system boundary
With system name
Particularly when
A sub-system of
A larger model
The actor can be another system (a class) –
In this case a library enquiry and reservation system
Which is modelled as a separate system
Electronic vs Personal reservation have different requirements
E.g. user authentication is inside vs outside the system
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Use Case Diagrams - Usage
Identification of Actors and functionalities
Requirements feed-back
To communicate to the clients what the providers have understood
a being the requirements
DANGER –
generalisations, extensions and inclusions
 make the diagrams too complex and technical for the clients to
understand properly
Test Case generation

Design Walk-throughs (sequence diagrams) of all Use Cases
Implementation tests for all Use Cases
To drive the system design (not a good use!)
Producing one module of code for each use case.
Leads to top down, function-oriented system
 Loses the maintainability and flexibility benefits of objectoriented design
Keep focus on requirements documentation

Include what is import for understanding system functionality
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Use Case Documentation
Each use case needs supporting by
documentation –
the name and diagram are not enough information
Generally, this would conform to some
organisation standard
An example
See
http://www.imsglbal.org/es/esv1p0/imes_usecasev1p0.html
for full examples using an extension this format
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Documentation - Essentials
Title:
Return Overdue Book
Brief Description
BookReturner hands book (copy) for return to Clerk
and the system detects that the book is overdue
Actors:
BookReturner: A user of the Library
Clerk: A library employee in the clerical role
Stakeholders (those benefiting from this
functionality)
Users: want their return of books recorded
Clerks: want to be seen to be doing their job properly
Administrators: Want to be able collect fines; want to
ensure records are up-to-date
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Documentation - Details
Triggers
The BookReturner spontaneously decides to return
the book, or has been prompted by a reminder
Basic Flow of events
BookReturner hands book to Clerk.
Clerk enters book return into system.
System informs clerk that is over-due and what the
fine is.
Clerk negotiates actual or deferred payment with
BookBorrower, and enters outcome to the system
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Documentation - Details
Pre-conditions
The period of loan terminated by this book return is
greater than that allowed for this type of user and
this type of book.
Post-conditions
The payment of a fine is recorded, or the clerk agrees
a deferred payment which is recorded.
Exception Handling
Related Use Cases:
Defer Fine
Pay Fine by Credit Card
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CLASS DIAGRAMS
Overview –diagram types
Use Case –
Class Object –
Collaboration –
Sequence –
State –
Activity Packages Deployment -
more details
more detail
new
new
more detail
new (appreciation only)
new (appreciation only)
new (appreciation only)
new (appreciation only)
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Class Relationships
User
Student
Item
Staff
Copy
Book
Journal
Generalisation (= Inheritance)
Class relationship –
Every instance of Staff is an instance of User
Every operation of User is an operation of Staff
Every Attribute of User is an attribute of Staff
Every association of User is an association of Staff
This is model, not implementation
Not necessarily “code re-use”
For a O-O language implementation –
might not be implemented as sub-class
(Implementation language might not be O-O)
Its for understanding structure –
although probably will drive implementation
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Article
Associations
User
Item
borrows
Student
Staff
Copy
Is copy
of
Book
Is part
of
Journal
contains
Article
borrows
Orders print-off
Associations – knows about
Instance oriented - A staff instance may order print-off of an
article
Often can only be understood by drawing instance example –
object diagram
Class diagram records the potential actual associations, and
defines some characteristics
Name is associated with a line-end –
 role name - what role the associated object plays for the other
object
 Usually name at most one end
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Associations
User
Item
borrows
Student
Staff
Copy
Is copy
of
Book
Is part
of
Journal
contains
Article
borrows
Orders print-off
Associations – knows about
Subsumes entity/relationship diagrams for showing data
structures
Subsumes inter-connection diagrams for showing which entities
communicate
Conceptual View (user communication)
there is an association if there is a relevant real-world association
– “a student can borrow a book”
Implementation View (design)
A (navigable) association implies a class has an attribute of the
associated type, and vice-versa
Don’t duplicate attributes and associations
 Copy does not need to show attribute – isCopyOf : Book
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Aggregation and Composition
Journal
Article
composition
Author
(other) aggregation
Special Associations
Aggregation – To model a collection of things
Journal has a collection of Articles
Article has a collection of Authors
Composition
A special case of aggregation – “ownership”
Part can only belong to one whole
The part cannot exist without the whole
Role name
Not given explicitly – implicit in the line end-point –
“is part of”
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Multiplicities
Student
Number of Copy objects that can
be associated with one student
object : At least 0; At most 6
0..1
0..6
borrows
Staff
Copy
1..*
0..12
0..1
0 or
1
1
Is copy
of
Exactly 1
Book
At least 1,no upper limit
Constrains the number of instance of one end
that can be associated with one instance
of the other end (in this association type, at any one time)
Either – single number (usually 0 or 1)
Or range X .. Y.
* for Y means no upper limit
Can also do set of ranges –
1..5 , 8..20
(hard to find an example!)
Composition (“owner”) implies 1
Note – “borrows” has become “has on loan” !!!!! –
structure rather than interaction
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Navigability
borrows
Copy
Is copy
of
borrows
Book
One-way
from copy to the
Book it is a copy of
Is copy
of
Copy
Book
Two-way
Also From a Book to any of its copies
Arrow-head means the association can be followed in
the direction shown
In implementation view, navigability requires attributes
to hold the link(s)to associated object(s)
How to show navigability and aggregation?
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Attribute / Operation Visibility
Item
Book
- Title : String
Journal
Visibility
+
public
#
~
-
protected
package
private
+ copiesOnShelf() : Integer
accessed by any client of the class –
default for operation
typically from same class or sub-class
typically anything in the same package
typically, from the same class default for attribute
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OBJECT DIAGRAMS
Overview –diagram types
Use Case –
Class Object –
Collaboration –
Sequence –
State –
Activity Packages Deployment -
more details
more detail
new
new
more detail
new (appreciation
new (appreciation
new (appreciation
new (appreciation
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only)
only)
only)
only)
Complex Class Structures
0..*
Book
by
0..*
1..*
Author
1..*
1
Division
1
by
0..*
Part
0..* contains
Chapter
The intended structure would be elucidated by
giving some examples !
Particularly if audience is not familiar with this
particular view on the possible structure of
book
So illustrate the class diagram by one or more
instance diagrams
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Object Diagram
0..*
1..*
Book
by
1
Class Diagram
0..*
0..* contains
Division
1
Author
by
1..*
0..*
Part
Chapter
B1: Book
Title: UML & WSDL
Object Diagram
A1: Author
Name: Richard
A2: Author
Name: Guy
C111: Chapter
Title: Classes
P11: Part
Title: UML
A2: Author
Name: David
P12: Part
Title: WSDL
C112: Chapter
Title: Use Cases
Object Diagram does not show full range of possibilities
The lines are “links” – instances of associations
Can annotate links with navigability and role if useful
Special case of collaboration Diag.
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COLLABORATION DIAGRAMS
Overview –diagram types
Use Case –
Class Object –
Collaboration –
Sequence –
State –
Activity Packages Deployment -
more details
more detail
new
new
more detail
new (appreciation
new (appreciation
new (appreciation
new (appreciation
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only)
only)
only)
only)
Collaboration Diagrams
Book
Borrower
theUser: User
suspended: No
theCopy: Copy
theBook: Book
To show an example of message passing interaction between
objects
Links - instances of class associations
Actors/Objects –
Show name and type
Can show values for objects where useful
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Collaboration Diagrams
1: borrow (theCopy)
Book
Borrower
theUser: User
suspended: No
1.2: borrow ()
theCopy: Copy
1.2.1: borrowed()
1.3: borrowStatus
1.1: okToBorrow
theBook: Book
Messages – actual messages passed,
Can show operation invoked at destination
Use self-messages to indicate internal
condition testing
Use structured sequence numbering scheme
1.1 – first message produced as a result of
receiving message 1
1.2 - second message produced as a result of
receiving message 1
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Collaboration Diagrams
1: borrow (theCopy)
Book
Borrower
theUser: User
suspended: No
1.2: borrow ()
theCopy: Copy
1.2.1: borrowed()
1.3: borrowStatus
1.1: okToBorrow
theBook: Book
Shows same kind of information as sequence diagram
But with emphasis on object structure, rather than time
sequence
Both are interaction diagrams
Sequence diagrams also have attribute values, if useful
Same Structured sequence numbering
Generally, Sequence diagrams more useful for understanding
system behaviour – shows the time sequence more clearly
Use collaboration diagrams without specific messages, to
exemplify system interconnection structure
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SEQUENCE DIAGRAMS
Overview –diagram types
Use Case –
Class Object –
Collaboration –
Sequence –
State –
Activity Packages Deployment -
more details
more detail
new
new
more detail
new (appreciation
new (appreciation
new (appreciation
new (appreciation
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only)
only)
only)
only)
Simple Sequence Diagram
Book
Borrower
theUser: User
1: borrow(theCopy)
theCopy: Copy
theBook: Book
t
i
m
e
1.1: okToBorrow
1.2: borrow()
1.2.1: borrowed()
borrowStatus
Sending a message
Object existence lifeline
Period of activation
The reply
Shows all replies ; Uses structured sequence numbering
1
BookBorrower invokes the use case -activates corresponding theUser object
1.1 theUser checks whether this is OK – self message
1.2 theUser tells theCopy object that it is now borrowed – it changes its state
1.2.1. theCopy tells theBook that it has been borrowed –
it reduces its count of available copies
Reply - theUser confirms success to BookBorrower
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Creation and deletion
Librarian
CreationLifeline starts
As a result
of message
theCatalogue:Catalogue
registerBook(theBook)
createBook(theBook)
theBook: Book
Librarian
theCatalogue:Catalogue
theBook: Book
Deletion Lifeline ends
Marked by a cross
removeBook(theBook)
destroy()
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So Far – Synchronous Messages
Librarian
theAccounts:Accounts
mailer: MailingLIst
loseUser
owesMoney
loseUser
Synchronous – the sender suspends until receives reply
So no need for reply to be explicit
Explicit reply to a synchronous message
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Asynchronous
Librarian
theAccounts:Accounts
mailer: MailingLIst
loseUser
loseUser
owesMoney
Asynchronous – the sender retains control and can
send and receive further messages
other versions of arrow heads are also used
Unspecified (simple) – could be synchronous or
asynchronous
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STATE DIAGRAMS
Overview –diagram types
Use Case –
Class Object –
Collaboration –
Sequence –
State –
Activity Packages Deployment -
more details
more detail
new
new
more detail
new
(appreciation only)
new (appreciation only)
new (appreciation only)
new (appreciation only)
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Basic State(chart) Diagrams
In Wings
On Loan
On Shelf
In Bindery
Reserved on Shelf
Reserved In Bindery
Statechart
For Copy
Class
Based on finite state machine concept
Identifying all the different states a discrete-state system can be in
Identify all the possible transitions between states
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Basic State(chart) Diagrams
In Wings
Catalogue()
On Shelf
Rebind()
Reserved()
Borrow()
In Bindery
Statechart
For Copy
Class
Reserved()
Return()
On Loan
Reserved on Shelf
Rebind()
Reserved In Bindery
UML Statecharts
Generic life history of objects of a particular class
Named states; Transition arrows
Can associate a “trigger” with a transition ; e.g. receive particular
message
Dummy states
 Start State
 Final states
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Basic State(chart) Diagrams
In Wings
Catalogue()
On Shelf
Rebind()
Reserved()
Borrow()
In Bindery
Statechart
For Copy
Class
Reserved()
Return()
On Loan
Reserved on Shelf
Rebind()
Reserved In Bindery
Conveys a lot of information
E.g. Can’t remove a copy till its been catalogued –
right?; Some problems?
A basic state diag. is easy to read
Therefore a good vehicle for requirements clarification
Important to choose level of abstraction
Actual book implementation will have more states
Whether to show trigger
Note – it’s a book, not a copy that gets reserved!! –
this was just to make a more interesting example
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Statecharts
Full capabilities give programming language expressivity
Most useful are –
Guards – express conditions
Compound states - abstraction
Guard
identify (internal) condition on
transition being possible
Trigger [guard]
On Shelf
Reserved() [not shortTermCopy]
Reserved on Shelf
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Compound States - Abstraction
In Wings
Catalogue()
On Shelf
Rebind()
In Bindery
Reserved()
Borrow()
Reserved()
Return()
On Loan
Rebind()
Reserved on Shelf
On Shelf +
Rebind()
Reserved In Bindery
In Bindery
Reserved()
Borrow()
Reserved()
Return()
On Loan
Reserved
Give separate statechart for Reserved and On Shelf +
And / or show them in-place as compound state
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FURTHER DIAG. TYPES
Overview –diagram types
Use Case –
more details
Class more detail
Object –
new
Collaboration –
new
Sequence –
more detail
State –
new
Appreciation only



Activity
Package
Deployment
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Activity
A flow-chart
Used to develop implementation of object
Also used for business level modelling
Just give a business level example
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Business Activity Diagram
user
librarian
[borrower] Find Book
on shelf
[returner]
Wait in
queue
[returning]
[borrowing]
Record
return
Record
return
Put book back
On shelf
finalise
decision
[guard]
transition
description
activity
Start / stop
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Synchronisation bar –
Start/collect concurrent activities
“concurrent” = non-sequenced
Any order or parallel
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Packages
User
Item
borrows
Student
Staff
Copy
Is copy
of
Book
Is part
of
Journal
contains
Article
borrows
Orders print-off
User
To do with items
items
Student
Dependency on
something in
the package
Staff
Group any collection of elements and into a named package
which can be included in diagrams which depend on the
package
Any collection of components
Used in any type of diagram
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Packages
Possible reasons for use
Just to hide irrelevant detail
To reflect implementation team structure
Factor the design process
Create different namespaces


Names must be unique within package
Full name is package-name::element-name
Control visibility –
and thus reduce dependencies
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Deployment and Components
Component (here) –
“a distributable piece of an implementation
of a system, including S/W code , but also
including business documents etc. in a
human system”
A WSDL definition could usefully viewed as
a component
Deployment Diagram shows –
Hardware items and physical communication
links
Location of components on H/W items
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Deployment/Component Example
User’s:PC
B:Browser
<<Internet>>
Univ:Server
Clerk’s:PC
<<LAN>>
P:Portal
L:Library
System
Shows Hardware Structure
Shows an example of intended deployment
Shows component dependencies –
Design/Implementation of Portal depends onCharacteristics of expected user browers
Interface to Library System
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Summary
Requirements
Use Case Diag.
Document requirements
Structured with extension/inclusion/specialisation
Provides a handle for the supporting documentation,
which is essential –
use-case diag. itself can be fairly vacuuous
Structure
Class Diag.
Develop structure of objects in system
Classes of objects provide the basis for subsequent
diagrams
Central step in firming up the system
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Summary
Behaviour – Draws out detail
1. Track one example through multiple participants
Show how different participants interact in one case
Sequence Diag.
Walk-through of particular use-case
To show details of behaviour and interactions
Important clarifications
Collaboration Diag.
Same role as sequence diagrams, but 
Emphasises Object linking structure

Sequence of events less clear

Less useful than Sequence Diagram
Special case is Object diagram (really structure)

For providing examples to elucidate complex class
structures
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Summary
Behaviour – Draws out detail
1. Track one example through multiple participants
Show how different participants interact in one case
2. Tracks one participant through all alternative
interactions –
Shows how different cases interact for one participant
the orthogonal perspective
State(chart) Diag.
States and transitions between them
Triggers and guards
Activity Diagram
Flow chart
Can show concurrency and multiple participants
Most useful is for modelling overall enterprise
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Summary
Supplementary
Packaging
Cut the model up into manageable pieces
Component Deployment
Show how the model elements manifest in
the real world
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An Overall Development Process
Partially articulated
requirements
Capture
Requirements
REQUIREMENTS
Use Case Diag.
Construct
Model of
Overall
system
Class Diag.
Sequence Diag.
Collaboration Diag
Single case
multi-participant interaction
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Deployment Diag..
STRUCTURE
BEHAVIOIUR
State Diag.
Activity Diag.
Single participant
multi-case interaction
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END
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Practical Work
Use of the Poseidon Tool (Community
version)
Examples of inputting given diagram
Putting in some diagrams you have invented
Requires some UML diagram creation,
to do manually beforehand –
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1. Class Diagram Exercise
Define a Class Diagram
For a Journal series – probably mythical
Such that the it can support the
requirements –
Users being able to do searches on:



author,
keyword,
….. (anything else you think appropriate)
Staff being able to find out the status –



On-the-shelf
Being-bound
… (anything else you think appropriate)
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2. Remote Borrowing Example
We add to the Library System the requirement that
 a member of staff can electronically submit a request to
borrow an item
if successful, the request results in
 the item being posted to them in the internal University
snail-mail system.
the use case(s) for this must include verifying the
staff members identity
Do (at least)
a sequence diagram for this remote-borrowing case
A use-case diagram that combines
 The remote borrowing case
 The normal case – user physically going to the library
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