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Modeling abstract messages, CSPA Exercises


  • Focus for abstract messages is to find out and model the information that is needed to communication part in the system.
    • Concrete message definitions, ie. encodings over bit-stream are done separately.
  • Analogy
    • Abstract message == ASN.1 syntax definition
    • Concrete message == ASN.1 codec definition

Modeling elements

  • Interfaces
    • operation names in interfaces as messages
  • Classes representing messages
    • attributes to express message data
      • type (primitive type or more complex data type structures)
      • field name
      • default value if any
    • Inheritance of classes
  • Dependency relationship to connect logical things
  • Text comments when needed

Design Notes

  • Create a scheme also how messages or message types are identified.
  • Definition of types have to be exact and complete, for example a type String have to also specify a character encoding that is used.

Task A

Model abstract information messages for a library system.

Task B

Model abstract information messages for a graphical navigation system.