The document discusses Unified Modeling Language (UML) which is a standard language used to specify, visualize, construct and document software systems. UML helps visualize a system, specify its structure and behavior, provide a template for construction and means of documentation. It includes various diagram types like class, sequence, use case diagrams to model different aspects of a system.

1. Unified Modeling Language
(UML)
“Design representations are useful in that they externalize a
designer’s ideas so that they maybe subject to analysis,
evaluation, and comparison with alternative designs; act as a
blueprint for those implementing the design; and document the
final design for those performing later maintenance and
extension.”

2. Unified Modeling Language (UML)
The Importance of Modeling:
• It helps us to visualize a system.
• It enables us to specify structure and behavior of a system.
• It provides a template to aid construction of a system.
• It provides a means of documentation.
What is UML?
Unified Modeling Language (UML) is the standard language for
specifying, visualizing, constructing, and documenting all the
artifacts of a software system.

3. UML stands for:
• Unified
– Unifies objected oriented modeling techniques of Grady Brooch, Jim
Rumbaugh and Ivar Jacobson
• Modeling
– The models
• Visualize a system
• Specify structure and behavior
• Provide a template to aid construction of a system
• Provide a means of documentation
• Language

4. Principles Of Modeling
• No single model is sufficient. Every non-trivial system is best
approached through a small set of nearly independent
models.
• Best models are connected to reality. (visualization)
• Models are expressed at different levels of precision.
(specification)
• Models have profound influence on how a problem is shaped
and attacked. (construction)

5. Features of UML
– UML is a language to help in design and documentation
– It is a current standard by the OMG (Object Management Group)
– Currently UML version 1.4.2 is an accepted ISO specification
• Available Specifications of the UML, version 2.2 can be found at
http://www.omg.org/technology/documents/formal/uml.htm
– It can express systems other than computer systems
– It can be used for representing the components and organization
of an object oriented system
– Being a semi-formal, high-level, graphical representation, it allows
for easy visualization and communication to others
– It is independent of the language of implementation.

6. Some features of UML:
 It can express systems other than computer systems.
 It is independent of the language of implementation.
 UML offers modeling for both aspects of object-oriented
design:
Static view
It represents the structure of the system.
Dynamic view
It shows how system entities/objects behave or, collaborate to solve the
problem.

7. Classification of Diagram Types
Diagram
Behavior
Diagram
Structure
Diagram
Class
Diagram
Composite
Structure Diagram
Object
Diagram
Activity
Diagram
Use Case
Diagram
State Machine
Diagram
Interaction
Diagram
Component
Diagram
Deployment
Diagram
Package
Diagram
Sequence
Diagram
Communication
Diagram
Interaction
Overview
Diagram
Timing
Diagram

8. Elements of UML
Structural
Diagrams
Behavioral
Diagrams
Model Management
Diagrams
Class Diagrams Use Case Diagrams Packages
Object Diagrams State Chart Diagrams Models
Component Diagrams Activity Diagrams Subsystems
Deployment Diagrams Interaction Diagrams
• Sequence Diagrams
• Collaboration Diagrams

9. Structural Diagrams: Class & Object Diagrams
• Class diagrams give a static and logical view
of the system in terms of classes and their
relationships
• They can be used at various levels of
abstraction
– Conceptual
– Specification
– Implementation
• Object diagrams represent individual objects
created from a class

10. Structural Diagrams: Class & Object Diagrams
• A good class diagram:
– Focuses on communicating one aspect of
system’s static design view
– Contains only elements essential to
understanding that aspect
– Provides detail consistent with its level of
abstraction
– Is not so minimalist as to misinform readers
about important semantics

11. Sample Class & Object Diagrams
Fraction
- top: int
- bottom: int
- DDVAL: int = 1 {invariant}
+ display ()
+ add (f1: Fraction):Fraction
myFraction: Fraction
- top = 1
- bottom = 5
Class Diagram: Object Diagram:

12. More Class Diagrams
ChatServer
Component which will take
all incoming connections
and keep communication
with chat clients
ChatServer
getNewConnections()
manageConnections()
sendOut()
ChatServer
- nameChatter : String
- message : String
- connections : Collection
- socketListener : Socket
+ getNewConnections()
+ manageConnections()
+ sendOut()
Class Diagrams at different levels of abstraction:
Conceptual Specification Implementation

13. Notation

14. More Notation

15. Aggregation/Composition

16. Relationships Modeled by UML
Four types of relationships modeled by UML are:
• Dependency
• Generalization
• Realization
• Association 8.. *1.. *
1 64
multiplicity
aggregation
composition

17. • Dependency
– Using relationship
– One-way relationship
– Denoted by: --------------->
Dependency Relationship
Stack
push(element:T)
T pop()
intStack charStack

18. Generalization Relationship
• Generalization
– ‘is a’ relationship
– Denoted by:
Student
Undergraduate StudentGraduate Student
School of Arts
& Sciences
School of
Engg.
…

19. Realization Relationship
• Realization
– One/more classes may realize/implement an
interface
– Denoted as:
<<interface>>
f1( )
f2 ( )
class1
class2

20. Association Relationship
Multiplicity
• Multiplicity - a specification of the number of possible occurrences of
a property, or the number of allowable elements that may participate
in a given relationship. (*)
• Minimum:
• Mandatory: 1
• Optional: 0
• Maximum:
• Forbidden: 0
• Only one: 1
• Many -*
• Represented as min..max pairs: 0..0, 0..1, 0..*,1..1, 1..*

21. Association Relationship
• For each association, multiplicity specifies the rules about the number of
times one class is related to the other

22. Association Relationship
• For each association, multiplicity specifies the rules about the number of
times one class is related to the other

23. Association Relationship
• For each association, multiplicity specifies the rules about the number of
times one class is related to the other

24. Association Relationship
• For each association, multiplicity specifies the rules about the number of
times one class is related to the other

25. Association Relationship
• For each association, multiplicity specifies the rules about the number of
times one class is related to the other
An operating room could be used for multiple operations
The fewest of 0 operations and multiple operations for maximum
An operation is performed in how many operating rooms.
One operation has to be performed in one operation room
An operation is going to be associated with 1 and only one operating room.

26. According to the following requirements the diagram on the next slide relates to the following points:
• A piece of equipment should be used in 0 operations as a minimum
• And over time it is going to be used in many operations
• An Operation could be performed using no equipment
• An Operation could be performed using many pieces of equipment.
• An Operation could be performed without receiving any cash receipt
• An Operation is associated with many cash receipt
• An operation is performed by 1 and only one doctor
• A doctor could perform 0 operations or many operations
• An operation is assisted with one or many nurses
• A nurse performs 0 or many operations
• Operation is performed on one and only one patient
• A patient could perform 0 operations or many operations
• Cash receipt is received by one and only one accounts receivable
• Internal agent could have done 0 or many Cash receipts
• The cash receipt came from one and only one insurance company
• The insurance company could have given us 0 or many cash receipts
• A cash receipt is entered in one and only one cash account
• A cash account could have been created with one cash receipt but over time we except to have
many cash receipts

27. Association Relationship

28. Association Relationship
• Association
– A structural relationship
– Two kinds:
• Aggregation – ‘part of the whole’ relationship
e.g.
• Composition – ‘part of the whole’ relationship and
‘whole owns part’
e.g.
Major Core Courses
1.. * 8.. *
Maze Position1 64

29. Behavioral Diagrams: Use Case Diagrams
• Related terminology:
– Use case:
A set of scenarios which describe all relevant interactions of a user with
the system for the purpose of achieving a user’s goal
– Scenario:
one particular sequence of events (a single thread of a use case)
– Actor:
a role a user plays in interacting with a system
– one user can play different roles in different cases
– Actors may be human/ non-human systems
use case
name
Actor name
Association /
communication
name

30. Student
System
Administrator
Sample Use Case Diagram
add a course
1. Finds an acceptable course
2. Fills an add form
3. Goes to registrar
4. Registrar verifies student info and
availability of course
5. Student pays the course add fee by
credit card (alternative scenarios
possible at this stage: -credit card not
approved -fee waived if on
scholarship)
6. Registrar enters student in the
enrollment database
7. Student receives the receipt and
class confirmation
Add a
course
Drop a
course
Confirmation
by registrar
Start/stop
registration
server
.
.
.
Use cases can be either written or drawn:

31. Behavioral Diagrams: Interaction Diagrams
• Interaction diagrams show how objects in a system interact/
work together
• Two types of interaction diagrams:
– Sequence diagrams
– Collaboration diagrams
• Sequence Diagrams
– Show a time-ordered series of method invocations among a set of
objects
– The vertical axis represents time; time flows from top of diagram to
the bottom
– The horizontal axis shows the object participating in the interactions

32. Sample Sequence Diagram
:Controller :Object1 :Object2
Request (arg 1,…)
result = op1(args1)
op2(result)
pass result
to object2

33. Behavioral Diagrams: State Chart Diagram
• A state chart diagram shows dynamic
behavior of a system from an outside
behavior
• It consists of states and transition conditions
from one to another
• It also includes information of the ‘start’ and
‘stop’ states of the system.
state-name
state-variables
activities state-name
A State An Initial State Representing
Termination
state-name
event
[condition]/ action;
action; … action;
Representing
Transitions
OR

34. [All items checked but
some not in stock]
Items Received
[All items
available]
Sample State Chart Diagram
Checking
do / check item
Dispatching
do / initiate
delivery
[All items
checked and
available]
Waiting
Delivered
do / close
start
/ get first
item
Delivered
[Not all items
checked ]
/ get next item