Classification, Generalization, and Specialization

1. Classification, Generalization, and Specialization

2. Classification • Objects with similar definitions have been grouped and defined into classes. • The act of identifying and categorizing similar objects into classes is known as classification in object-oriented modeling.

3. Example:List of Objects

4. Classification • We will group the animals based on their commonality with one another. • Mighty, Flipper, Willy, Janet, Jeremy, Bunny, and Smudge. These objects are grouped together into the Mammal category because they share some common information typical of a mammal: • their young are born alive; • they are warm-blooded; • they breathe through their lungs; and • their bodies are covered with hair.

5. Classification • Similarly, Parry, Heather, Wise, and Swift are grouped into a Bird category because they share common information typical of a bird. • In a like manner, we group: • Angel and Jaws into a Fish category; • Sally and Lily into a Reptile category; • Beatle and Ben into an Insect category; and • Kermit into an Amphibian category.

6. Categories of Object

7. Hierarchical Relationship of Classes • Classes formed can be organized in a hierarchical manner. • Depending on the position of a class in the hierarchy, it may be known as a superclass or a subclass of a class. • A specialized class is known as a subclass of a class while the generalized class is known as a superclass of a subclass in object-oriented terms.

8. A Class Hierarchy Diagram

9. Generalization • Generalization is the act of capturing similarities between classes and defining the similarities in a new generalized class; the classes then become subclasses of the generalized class.

10. Generalization

11. A Class Hirarchyfor animals