OBJECT ORIENTED MODELING AND DESIGN
OBJECT ORIENTED MODELING AND DESIGN.pptx (Size: 70.42 KB / Downloads: 41)
The purpose of class design is to complete the definitions of the classes and associations and choose algorithm for operations.
When we think that class design is complete at one level of abstraction, we should consider the next lower level of abstraction.
For each level we may need to add new operations, attributes and classes.
Class design involves the following steps
Bridge the gap from high level requirements to low level services.
Realize use cases with operations.
Formulate an algorithm for each operation.
Recurse downward to design operations that support higher level operations.
Refactor the model for a cleaner design.
Bridging the gap:
There is a set of features that we want our system to achieve and we have a set of available resources.
Consider the distance between them as a gap.
Our job is to build a bridge across the gap.
Because there is too big a gap between the features and the resources.
In this case, we must invent some intermediate elements, so that each element
can be expressed in terms of few elements at the next lower level.
Furthermore if the gap is large you will need to organize the intermediate elements into multiple levels.