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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.
Task A
Model abstract information messages for a library system.
Task B
Model abstract information messages for a graphical navigation system.