Modeling abstract messages, CSPA Exercises

Notes

• 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.

Model abstract information messages for a library system.

Model abstract information messages for a graphical navigation system.