Introduction to UML
Prashanth Aedunuthula
Fall, 2004
Acknowledgements
► All
the lecture slides were adopted from the
slides of Mr. Shiyuan Jin’s UML class, EEL
5881, Fall 2003.
Overview
► What
is UML?
► A brief history of UML and its origins.
► Understanding the basics of UML.
► UML diagrams
► UML Modeling tools
What is UML?
►
The Unified Modeling Language (UML) is a
industry-standard graphical language for
specifying, visualizing, constructing, and
documenting the artifacts of software systems,
as well as for business modeling.
►
The UML uses mostly graphical notations to
express the OO analysis and design of software
projects.
►
Simplifies the complex process of software
design
Why UML for Modeling
►
Use graphical notation to communicate more clearly
than natural language (imprecise) and code(too
detailed).
►
Help acquire an overall view of a system.
►
UML is not dependent on any one language or
technology.
►
UML moves us from fragmentation to
standardization.
History
Time
Year Version
2003:
UML 2.0
2001:
UML 1.4
1999:
1997:
UML 1.3
UML 1.0, 1.1
1996:
UML 0.9 & 0.91
1995:
Unified Method 0.8
Booch ‘93
OMT - 2
Other methods
Booch ‘91
OMT - 1
Types of UML Diagrams
Use Case Diagram:
Displays the relationship among actors and use
cases.
Class Diagram:
Describe the types of objects in the system and various kinds
of static relationship that exist among them.
Sequence Diagram:
Displays the time sequence of the objects
participating in the interaction.
Types of UML Diagrams
Collaboration Diagram
Displays an interaction organized around the
objects and their links to one another.
State Diagram
Displays the sequences of states that an object
of an interaction goes through during its life in
response to received stimuli, together with its
responses and actions.
Use Case Diagram(core components)
Actors: A role that a user plays with respect to the
system,including human users and other systems.
e.g.,inanimate physical objects (e.g. robot); an external
system that needs some information from the current system.
Use case: A set of scenarios that describing an
interaction between a user and a system.
System boundary: rectangle diagram representing the
boundary between the actors and the system.
Use Case Diagram(core relationship)
Association: communication between an actor and
a use case; Represented by a solid line.
Generalization: relationship between one general
use case and one specific use case.
Represented by a line with a triangular arrow head
toward the parent use case.
Use Case Diagram(core relationship)
Include: a dotted line labeled <<include>> beginning at base
use case and ending with an arrows pointing to the include use
case. The include relationship occurs when a chunk of
behavior is similar across more than one use case. Use
“include” in stead of copying the description of that behavior.
<<include>>
Extend: a dotted line labeled <<extend>> with an arrow
toward the base case. The extending use case may add behavior to
the base use case. The base class declares “extension points”.
<<extend>>
Use Case Diagrams
Boundary
Use Case
Actor
Library System
Borrow
Employee
Client
Order Title
Fine Remittance
Supervisor
• A generalized description of how a system will be used.
• Provides an overview of the intended functionality of the system
Use Case Diagrams(cont.)
(TogetherSoft, Inc)
Use Case Diagrams(cont.)
•Pay Bill is a parent use case and Bill Insurance is the
child use case. (generalization)
•Both Make Appointment and Request Medication
include Check Patient Record as a subtask.(include)
•The extension point is written inside the base case
Pay bill; the extending class Defer payment adds the
behavior of this extension point. (extend)
Class
►
Each class is represented by a rectangle subdivided into three
compartments
 Name
 Attributes
 Operations
►
Modifiers are used to indicate visibility of attributes and operations.
 ‘+’ is used to denote Public visibility (everyone)
 ‘#’ is used to denote Protected visibility (friends and derived)
 ‘-’ is used to denote Private visibility (no one)
►
►
By default, attributes are hidden and operations are visible.
The last two compartments may be omitted to simplify the class
diagrams
An example of Class
Account_Name
- Custom_Name
- Balance
+AddFunds( )
+WithDraw( )
+Transfer( )
Name
Attributes
Operations
Multiplicity and Roles
student
1
*
University
Person
0..1
employer
Multiplicity
Symbol
Meaning
1
One and only one
0..1
Zero or one
M..N
From M to N (natural language)
*
From zero to any positive integer
0..*
From zero to any positive integer
1..*
From one to any positive integer
*
teacher
Role
Role
“A given university groups many people;
some act as students, others as teachers.
A given student belongs to a single
university; a given teacher may or may not
be working for the university at a particular
time.”
Class Diagram
Name
Order
Attributes
Operations
-dateReceived
-isPrepaid
-number :String
-price : Money
*
Association
-name
-address
+creditRating() : String()
{if Order.customer.creditRating is
"poor", then Order.isPrepaid must
be true }
(inside braces{}}
Generalization
Corporate Customer
Personal Customer
-contactName
-creditRating
-creditLimit
-creditCard#
Constraint
Multiplicity:
Many value
Customer
1
+dispatch()
+close()
1
class
Multiplicity: mandatory
+remind()
+billForMonth(Integer)
*
Multiplicity:
optional
0..1
Employee
*
OrderLine
-quantity: Integer
-price: Money
-isSatisfied: Boolean
*
[from UML Distilled
1
Product
Third Edition]
OO Relationships: Generalization
Supertype
Example:
Customer
Regular
Customer
Subtype1
Loyalty
Customer
Subtype2
or:
Generalization expresses a
relationship among related classes.
It is a class that includes its
subclasses.
Customer
Regular
Customer
Loyalty
Customer
OO Relationships: Composition
COMPOSITION
Whole Class
Composition: expresses a relationship among instances
of related classes. It is a specific kind of Whole-Part
relationship.
Class W
It expresses a relationship where an instance of the
Whole-class has the responsibility to create and initialize
instances of each Part-class.
Class P1
Class P2
Part Classes
Composition should also be used to express relationship where
instances of the Whole-class have exclusive access to and
control of instances of the Part-classes.
Example
Automobile
Engine
It may also be used to express a relationship where instances
of the Part-classes have privileged access or visibility to
certain attributes and/or behaviors defined by the
Whole-class.
Composition should be used to express a relationship where
the behavior of Part instances is undefined without being
related to an instance of the Whole. And, conversely, the
behavior of the Whole is ill-defined or incomplete if one or
more of the Part instances are undefined.
Transmission
[From Dr.David A. Workman]
OO Relationships: Aggregation
Container Class
Aggregation: expresses a relationship among instances
of related classes. It is a specific kind of ContainerContainee
relationship.
Class C
AGGREGATION
Class E2
Class E1
Containee Classes
Example
It expresses a relationship where an instance of the
Container-class has the responsibility to hold and
maintain
instances of each Containee-class that have been created
outside the auspices of the Container-class.
Aggregation should be used to express a more informal
relationship than composition expresses. That is, it is an
appropriate relationship where the Container and its
Containees can be manipulated independently.
Bag
Aggregation is appropriate when Container and
Containees
have no special access privileges to each other.
Apples
Milk
[From Dr.David A. Workman]
Aggregation vs. Composition
•Composition is really a strong form of aggregation
•components have only one owner
•components cannot exist independent of their owner
•components live or die with their owner
e.g. Each car has an engine that can not be shared with
other cars.
•Aggregations may form "part of" the aggregate, but may not
be essential to it. They may also exist independent of the
aggregate.
e.g. Apples may exist independent of the bag.
Sequence Diagram(make a call)
Caller
Phone
Recipient
Picks up
Dial tone
Dial
Ring notification
Ring
Picks up
Hello
Sequence Diagram:Object interaction
A
Self-Call: A message that an
Object sends to itself.
B
Synchronous
Asynchronous
Condition: indicates when a
message is sent. The message is
sent only if the condition is true.
Transmission
delayed
[condition] remove()
Condition
*[for each] remove()
Iteration
Self-Call
Sequence Diagrams – Object Life Spans
►
►
►
Creation
A
 Create message
 Object life starts at that point
Activation
 Symbolized by rectangular stripes
 Place on the lifeline where object
is activated.
 Rectangle also denotes when
object is deactivated.
Activation bar
Deletion
 Placing an ‘X’ on lifeline
 Object’s life ends at that point Lifeline
Create
Return
B
X
Deletion
Sequence Diagram
User
Message
Catalog
Reservations
1: look up ()
2: title data ()
3: [not available] reserve title ()
4 : title returned ()
5: hold title ()
5 : title available ()
6 : borrow title ()
6 : remove reservation ()
•Sequence diagrams demonstrate the behavior of objects in a use case
by describing the objects and the messages they pass.
•The horizontal dimension shows the objects participating in the interaction.
•The vertical arrangement of messages indicates their order.
•The labels may contain the seq. # to indicate concurrency.
Interaction Diagrams: Collaboration diagrams
start
6: remove reservation
3 : [not available] reserve title
User
Reservations
5: title available
6 : borrow title
2: title data
1: look up
4 : title returned
Catalog
5 : hold title
•Shows the relationship between objects and the order of messages passed between them.
between them.
•The objects are listed as rectangles and arrows indicate the messages being passed
•The numbers next to the messages are called sequence numbers. They show the sequence
of the messages as they are passed between the objects.
•convey the same information as sequence diagrams, but focus on object roles instead of the
time sequence.
CRC Card
(Class Responsibility Collaborator)
Benefits: It is easy to describe how classes work by
moving cards around; allows to quickly consider
alternatives.
Class
Reservations
Responsibility
• Keep list of reserved titles
• Handle reservation
Collaborators
•
Catalog
•
User session
State Diagrams
(Billing Example)
State Diagrams show the sequences of states an object goes
through during its life cycle in response to stimuli, together
with its responses and actions; an abstraction of all possible
behaviors.
End
Start
Unpaid
Invoice created
Paid
paying
Invoice destroying
State Diagrams
(Traffic light example)
Traffic Light
State
Transition
Red
Yellow
Green
Event
Start
UML Modeling Tools
►
Rational Rose (www.rational.com) by IBM
►
UML Studio 7.1 ( http://www.pragsoft.com/) by Pragsoft
Corporation
Capable of handling very large models (tens of thousands of
classes). Educational License US$ 125.00; Freeware version.
►
►
TogetherSoft Control Center; TogetherSoft Solo
(http://www.borland.com/together/index.html)
by Borland
ArgoUML (free software)
(http://www.apple.com/downloads/macosx/development_tools/argouml.html )
OpenSource; written in java
►
Others (http://www.objectsbydesign.com/tools/umltools_byCompany.html )
UML studio 7.1
Reference
1. UML Distilled: A Brief Guide to the Standard Object Modeling Language
Martin Fowler, Kendall Scott
2. Practical UML --- A Hands-On Introduction for Developers
http://www.togethersoft.com/services/practical_guides/umlonlinecourse/
3. OO Concepts in UML. Dr. David A. Workman, School of EE and CS. UCF.
4. Software Engineering Principles and Practice. Second Edition; Hans van
Vliet.