Model-Based Programming: Executable UML with Sequence Diagrams

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Model-Based Programming Executable UML with
Sequence Diagrams

• By Ruben Campos
• Cal State L.A.
• Computer Science Thesis Work
• Spring 2007

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Acknowledgements

• Dr. R. Abbott
• Dr. R. Soley, CEO of OMG

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Objective

• Design a conceptual xUML Engine to achieve true
  Model-Based Programming

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Strategy

• Understand xUML
• Understand the OMG Executable UML (xUML)
  specification titled Semantics of a Foundational
  Subset for Executable UML Models
• Understand/Critique Mellor/Balcer xUML
  Implementation
• Propose alternative design of conceptual xUML
  Implementation

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What is xUML?

• According to the OMG Executable UML will enable
  the following
• construction, verification, translation, and
  execution of computationally complete executable
  models.
• xUML will allow for a method by which a Software
  model can be directly executed

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OMG Specification

• Provided by Dr. Soley, CEO of OMG
• Objective Define runtime behavior for UML
  metamodel elements in order to enable a chain of
  tools that support construction, verification,
  translation, and execution of computationally
  complete executable models

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Executable UML Foundation Architecture

• The Foundational UML Subset (fUML)
• Executable subset of standard UML
• Used to define, in an operational style, the
  dynamic and static semantics of modeling
  languages (e.g. - standard UML)
• For example, the semantics of UML statecharts can
  be specified as a program written in fUML.
• The Basic UML Subset (bUML)
• A subset of fUML
• Has a corresponding mathematically formal
  semantics definition
• Used to specify the semantics of fUML
• Provides formal treatment of fUML programs
• Formal Specification
• Queens University Project to define formal
  semantics 5

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Mellor/Balcer xUML Design

• According to Balcer and Mellor 1 the steps to
  building an Executable UML model would be as
  follows
• Create Use Case and Domain Models simultaneously.
• Model Domains in the form of Class Diagrams
• Create Autonomous State Diagrams from the Class
  Diagrams
• State Diagrams will drive the creation of an
  Executable UML Model using Action Language
• Executable UML Compilers will compile an
  Executable UML into a Platform Specific Model

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Mellor/Balcer xUML Model Artifacts
Classes, State Diagrams, States, Actions, Action
Language
Domains and Bridges
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Mellor/Balcer Design Flaws

• Not Pure Model-Based Programming
• Reduce Role of Class Diagram
• State Diagram Centric
• Procedural Action Language

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Sequence Diagram Centric xUML Design

• xUML Model that uses Sequence Diagram for
  Execution
• Components include
• Use Case Diagram
• Sequence Diagram
• Class Diagram
• Activity Diagram
• Assumes UML Diagrams are semantically well-defined

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Well-Defined Sequence Diagram Example
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Well-Defined Activity Diagram Example
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Well-Defined Class Diagram Example
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Process for xUML Execution
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xUML Engine Architecture
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Observation

• Programming at some level of abstraction will
  always be required, even if its Model-Based
  Programming

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References

1. Mellor, Balcer, Executable UML, A Foundation for
   Model-Driven Architecture
2. OMG Draft Specifications
3. OMG UML 2 Superstructure
4. OMG UML 2 Infrastructure
5. Queens University Formal Semantics Project,
   http//www.cs.queensu.ca/stl/internal/uml2/index.
   html