Object Orientation. WHY: Try to model the data, not the tasks/procedures: Data change less often! Data is considered to be objects. Some more of the (claimed) benefits of using OOA&D methods. Increased abstraction Encouragement of cyclic development ; easy to revisit early stages
WHY: Try to model the data, not the tasks/procedures:
Data change less often!
Data is considered to be objects...
Some more of the (claimed) benefits of using OOA&D methods
An abstraction of something in a problem domain, reflecting
the capabilities of the system to keep information about it,
interact with it, or both; objects have crisp boundaries and meaning
for the problem at hand. They encapsulate state and behaviour.
The state of an object is represented by attributes and relationships.
Behaviour is represented by operations, methods and state machines.
An object represents a particular instance of a class.
A class is a description of a set of objects that share the same
attributes, operations, methods, relationships and semantics.
A use case model employs “actors” and “use cases” in order to depict a scenario of the system’s use.
Use case: a part of the system’s functionality.
Use case models can model functionality of entities
at different levels of abstraction
Use case models can be used for:
What use case modeling is:
What use case modeling is not:
To decompose or not to decompose? Tradeoffs…
Kenworthy E.: ”Use Case Modelling – Capturing User Requirements”,
...In one of the StarTrek movies, Cap. Kirk was in trouble, as usual.
He met an extremely beautiful lady who however thereupon
changed into a hideous troll. Kirk was quite surprised, but the lady
told him: ``Didn\'t you know I am a polymorph?\'\'