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					       UML

  By Adwait Moghe
CPSC 606 Presentation
                Overview
•   Introduction
•   History
•   Goals
•   Diagrams and Examples
•   Latest Changes
•   Disadvantages
•   Conclusion
                        What is UML?

• Unified Modeling Language (UML) is a standard language for
  specifying, visualizing, constructing software artifacts.

• Not necessarily restricted to software systems – used in business
  modeling.

• Has proven successful in modeling of large and complex systems.

• Uses graphical notations to describe the architecture of software.

• We have used UML in the diagrams for HEASSISTANT.
                              Goals
• Provide users a expressive, visual language to enable sharing of
  meaningful models.

• Enables developers to compare models before implementation
  phase.

• Independent of programming language and development process.

• Encourage growth of Object Oriented Tools market.
                            History
• First modeling languages – 1970’s.

• More than 50 modeling languages present during 1994. Lead to
  “method wars”.

• Methods began to incorporate each other’s techniques.

• In 1994, Grady Booch and Jim Rumbaugh (Rational Software
  Corporation) unified Booch and Object Modeling Technique
  methods to create UML.

• Ivar Jacobson incorporated the OOSE method in 1995, leading to
  UML version 0.9 in late 1996.
                        UML Versions
• UML 1.0 was created through a collaboration of various
  organizations: Microsoft, IBM, HP, etc.

• Today, UML is on Version 2.0.

• It is managed by the Object Management Group – not for profit
  consortium. UML specification is available for download at
  http://www.uml.org/

• Tools that conform the latest 2.0 specification – Rational Software
  Architect, Sparx System Architect, StarUML, etc.
               Types of UML Diagrams
• Types of UML diagrams (total of 13 – main ones shown below) :

•   Use case diagrams
•   Class diagrams
•   Interaction Diagrams - Sequence and Collaboration
•   State Diagrams
•   Activity Diagrams
•   Implementation Diagrams - Component and Deployment




• We have done some of these for HEASSISTANT.
               Use Case Diagrams




Use Case diagrams describe what a system does. HEASSISTANT
simply had 1 actor, but generally, we have multiple actors.
                        Class Diagrams




Note advanced additional features such as abstract classes,
generalization (inheritance), aggregation (orderdetails make up order)
Sequence Diagrams
Collaboration Diagrams

       • Note the use of sequence numbers
       • Top level is assigned 1.1 – additional dots
       per level away from the user interface.
                           State Diagrams




       Lifetime of a login class.
• Show the state of a particular object throughout the system lifetime.
• Not necessary for all objects – just the critical ones.
• Super states – can be used to nest states to make diagram easier to read.
                        ACTIVITY DIAGRAMS
• A flowchart of the activity in a system.


• Elegant way to show conditional flows of execution.


• For use in multithreaded environments – can show creation of parallel threads
of execution, stopping of threads of execution.


• Usually one per use case. Objects involved are given their own “swimlanes”.


• Example on next page shows activity flow for "Withdraw money from a bank
account through an ATM.“


• Activities in parallel – debiting account, removing money from slot.
         COMPONENT AND DEPLOYMENT DIAGRAMS




High level component communication and dependencies.
                     Certification
• OMG offers individual certification programs for UML 2.0
  with 3 levels – Fundamental, Intermediate, and
  Advanced.

• Price per exam is 200 dollars, but Fundamental is
  prerequisite to Intermediate.. etc.

• OMG also certifies UML compliant tools from vendors.

• Gives vendors right to place “OMG certified” logos on
  products and websites.
                   UML 2.0 Structure
• Comprised of four parts: superstructure, Infrastructure, Object Constraint
Language, Diagram Interchange


• Superstructure – defines the UML diagrams. Large 710-page PDF free to
download from OMG website.


• Infrastructure - defines the base classes/components used by the
Superstructure.


• Object Constraint Language – formal way of specifying constraints on objects
within a diagram defined in the Superstructure.


• Diagram Interchange – standard for exchange and storage/retrieval of UML
diagrams for different software tools.
                State of UML Today
• Size of the UML specification is growing tremendously.

• Changes are being made in the superstructure.
  Example – timing diagrams added but weren’t present in
  previous versions.

• Extensions to UML being written to handle other
  technologies – CORBA, certain Security extensions.

• Requests for Proposal (RFP) are found on OMG
  websites.
            Significant changes in 2.0
• Activity diagrams completely overhauled – OMG realized
  they were being used for business modeling instead of
  class modeling. Diagrams were made more similar to
  flowcharts.

• Package Diagrams added for high level overview of code
  structure.

• Collaboration diagrams renamed as communication
  diagrams but specification remains the same.

• Timing diagrams added for real-time applications.
               Disadvantages of UML
• Still no specification for modeling of user interfaces.

• Business rule specification – a group exists for this within
  the OMG, so we should see something in UML 2.1.

• Poor for distributed systems – no way to formally specify
  serialization and object persistence.

• Example – no way to specify that an object resides on a
  server process and shared among instances of a running
  process.
      Disadvantages to UML (continued)
• Requires training/certification when working with
  enterprise class systems – wasted resources.

• Management forcing UML on developers.

• Semantics too imprecise – leading to subjective
  interpretations while formal testing/verification… Leads
  to too many diagram notes.

• Too bloated… contains specifications needed very
  rarely.
             5 Questions
• What is UML?
• How has UML changed over its versions ?
  (currently 2.0)
• Who “manages” UML?
• What is the best tool for creating UML
  diagrams?
• Is UML restricted to OOP languages due
  to features such as class diagrams?
Questions?
 Thank you
               References
• http://www.uml.org/
• http://atlas.kennesaw.edu/~dbraun/csis465
  0/A&D/UML_tutorial/
• http://bdn.borland.com/article/0,1410,3186
  3,00.html
• http://en.wikipedia.org/wiki/Unified_Modeli
  ng_Language

				
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