UML

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UML Whats all the Fuss about?

• Simon Horwith
• CTO
• Etrilogy Ltd.

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Presentation Topics

• What is UML?
• Where did UML Come From?
• Why UML?
• How does UML work?
• UML facts and fiction

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What is UML?

• Unified Modeling Language
• UML is a standardized format for diagramming
  software and software processes.

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Where did UML Come From?

• In the late 1980s early 1990s
• n-tier client server application development
  became very popular
• C was the most widely used platform for the
  development of commercial software
• The growth in popularity of OO programming led to
  many different systems and ideas about how to
  represent an Object Oriented architecture with
  diagrams both for documentation and planning of
  software.
• The best predecessor to UML (called OMT) was
  described by its creators as essentially an
  extended Entity-Relationship approach. When UML
  was finally released as an official
  specification, the authors of OMT then
  distinguished UML as addressing programming
  applications while OMT addresses programming
  database applications

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Where did UML Come From? contd

• UML was released as a theoretical diagramming
  system in 1997 by the Object Management Group
  (http//www.omg.org) who still control and define
  UML
• UML has since become THE standard for diagramming
  Object Oriented applications
• This raises the question if UML is great for
  modelling OO Applications, what use is it when
  building web applications in ColdFusion?
• ColdFusion Applications can be developed in a
  very OO manner using CFCs and custom tags there
  are many benefits to approaching development as
  such

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Why UML?

• Do you ever work with databases?
• Do you plan these databases?
• Why? How?
• Do you plan your applications?
• Why? How?

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Why UML? contd

• Before asking Why UML?, first ask why Object
  Oriented CF Applications?
• In 1989, Biggerstaff and Richter suggested in a
  paper that less than half of any typical system
  can be built with reusable software components.
  To summarize their paper, it was concluded that
  the only way to obtain more significant gains in
  productivity and quality is to raise the level of
  abstraction of the components.
• An application is successful if it meets its
  original goals and its original goals must be
  clearly defined in order to develop an
  application and measure its success.

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Why UML? contd

• The benefits of Object Oriented Design are best
  summed up by Ian Graham as
• Required changes are localized and unexpected
  interactions with other program modules are
  unlikely
• Inheritance and polymorphism make OO systems more
  extensible, thus contributing to more rapid
  development
• Object-based design is suitable for distributed,
  parellel, or sequential implementation
• Objects correspond more closely to the entities
  in the

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Why UML? contd

• There are three main occurrences in any software
  development life cycle
• Specification and logical modelling (analysis )
• Architectural modelling (design)
• Implementation (coding and testing)
• UML helps to distinguish between the often
  overlapping specification and design origins of a
  software system

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How does UML work (in a nutshell)?

• You think
• You draw pictures
• You think more
• You might draw more pictures
• You code

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UML facts and fictions?

• OK so maybe your applications arent large
  enough to warrant diagramming all of your codeso
  that means UML is useless for you?
• What about sequences of events?
• Most applications begin with use cases
  diagramming these sequences helps to give clear
  vision to how your application is going to work
  and to what end users are going to experience.

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UML facts and fictions? contd

• UML is hard
• no its not. There are hundreds of UML books
  available (you can order UML for Dummies from
  Amazon for 20). There are also dozens of free
  and not so free tools that will generate diagrams
  for you.
• UML is a waste of time
• not likely certainly not for event sequence
  diagrams

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Im still not convinced

• Why?
• Because it requires learning?
• Because it requires purchasing and using new
  software
• Because my apps. Dont require it
• You probably already use UML and dont even know
  it!!
• If you diagram your apps (use a whiteboard its
  easy) you are using UML concepts just not their
  standards.
• You (your company) have some sort of standard
  naming conventions when you write code, right?
  Why not agree on a standard way to draw these
  pictures???