Unified Modeling Language UML

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Unified Modeling Language (UML)

• CSCI 6050 Software Engineering
• January 19, 2005
• Trentin Bishop
• Micah Lewis
• Amit Mathew
• Rufin Tshinanga
• Stephen Upchurch

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Why do we need models?

• To create a simplified representation of a real
  software system

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What is UML?

• A popular, standardized modeling language for
  object-oriented software
• The Object Management Group (OMG) is the group
  that dictates the UML standard
• Created by Grady Booch, James Rumbaugh, and Ivar
  Jacobson

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UML Models

• Functional Models
• Use case diagrams
• Structural Models
• Class diagrams
• Dynamic/Behavioral Models
• Statechart diagrams
• Sequence diagrams
• Activity diagrams

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UML Conventions

• Rectangles are classes or instances
• Ovals are functions or use cases
• Instances are underlined
• Types are not underlined

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Poseidon for UML

• Available from http//www.gentleware.com/
• Get the free Community Edition
• Caveat Slow on older computers, a little
  sluggish on newer ones

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Poseidon for UML demo
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Use case diagrams
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Use case diagrams

• Describes the functional behavior of the system
  from the users point of view
• Used during the requirements elicitation stage to
  represent external behavior
• Actor User, external system, or a physical
  environment
• Use case a class of functionality provided by
  the system as an event flow
• Has entry and exit conditions, flow of events,
  and participating actors

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Use case diagram symbols
Actor
Relationships
Use case
System
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Use case example
Report location
Find arrival times
Passenger
GPS System
Report error
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Use case example explanation

• Actors dont have to be people
• Shows how actors interact with the system
• Three use cases

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Class diagrams
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UML Class Diagram

• Depict the classes within the model
• Illustrates the class attributes (member
  variables), operations (member functions), and
  relationships with other classes

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UML Class Diagram Symbols
CLASS
Class Name
Number of links each class object may contain


Composition relationship Class 1 is composed of a
Class 2
Aggregation A collection of other classes
Inheritance relationship Class 2 and Class 3
derive from Class 1
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UML Class Diagram Example
SimpleWatch class contains 2 PushButtons 1
Display 2 Batteries 1 Time
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UML Class Diagram Example
http//pigseye.kennesaw.edu/dbraun/csis4650/AD/U
ML_tutorial/class.htm
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UML Class Diagram Example
The class Order is associated with the class
Customer The multiplicity denotes the number of
objects For example, Order object can be
associated only one customer but a
customer can be associated to many orders
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Statechart diagrams
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UML Statechart Diagram

• A statechart diagram shows the behavior of
  classes in response to external stimuli
• This diagram models the dynamic flow of control
  from state to state within a system.

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Basic Statechart Diagram Symbols and Notations

• States represent situations during the life of an
  object
• A solid arrow represents the path between
  different states of an object
• A filled circle followed by an arrow represents
  the object's initial state.
• An arrow pointing to a filled circle nested
  inside another circle represents the object's
  final state.

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Description of state chart diagram

• State
• Display alarm time
• Display clock time
• No sound
• Sound on
• Buzzing
• Playing radio
• Transition
• On
• Off
• Hold alarm
• Alarm switch off
• Change Hrs/Min
• Radio

• Activity
• Do/wait for clock time to alarm time

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Sequence diagrams
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Sequence Diagrams

• Describe the dynamic behavior between actors and
  the system and between objects of the system
• Used during requirements analysis
• To refine use case descriptions
• To find additional objects
• Used during system design
• To refine subsystem interfaces

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Sequence diagram notation

• Classes are represented by columns
• Messages are represented by arrows
• Activations represented by narrow rectangles
• Lifelines are represented by dashed lines

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Example- sequence diagram for SimpleWatch

• O
• - - SimpleWatch
  Display
  
  Time
• / \
  
  
  
• WatchUser
  
  
  
• pressButton1()
  blinkHours()
  
  
• ???????? ?????????????
  
  
• pressButton1()
  blinkMinutes()
  
  
• ???????? ?????????????
  
  
• 
  
  
  
• pressButton2()
  
  
  
• ????????
  
  incrementMinutes()
• 
  ???????????????????????????????
• 
  
  refresh()
• pressButton1And2()
  
  ??????????????
• ????????
  
  
  
• 
  
  commitNewTime()
  
• 
  ????????????????????????????????
• 
  
  
  
• stopBlinking()

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Example cont.

• -The left-most column represents the timeline of
  the WatchUser who initiates the use case.
• -The other columns represent the timeline of the
  objects that participate in this use case.

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Activity diagrams
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Activity Diagrams

• Used to represent the behavior of a system in
  terms of activities and their precedence
  constraints
• Compared to flowchart diagrams because
• They can be used to represent control flow (order
  in which operations occur)
• They can be used to represent data flow (objects
  exchanged among operations)
• The completion of an activity triggers an
  outgoing transition which may initiate another
  activity

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Symbols
- Synchronization of the control flow
- Activities in the system
- Transitions between activities
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Activity Diagram Example
Allocate Resources
Open Incident
Coordinate Resources
Archive Incident
Document Incident
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Example Explained

• The 1st activity initiated is Open Activity.
  After all the operations in this activity have
  been executed, the activities Allocate Resources,
  Coordinate Resources Document Incident are
  initiated. (Note There is a complex transition
  between Open Activity and the next three
  activities).
• These three activities may occur in sequence or
  concurrently.
• Even if the three activities dont occur
  concurrently, Archive Incident is not initiated
  until all three have been completed.

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References

• B. Bruegge, A. Dutoit. Object-Oriented Software
  Engineering Using UML, Patterns and Java, Second
  Edition. 2003.

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Questions?