CMPSC 56 Chapter Notes - Chapter 7-8: Subtyping, Function Overloading, Duplicate Code
Document Summary
Subclasses can add new methods and instance variables and they can override the methods it inherits from the superclass. Design a class that represents the common state and behavior. Decide if a subclass needs behaviors (method implementations) that are specific to that particular subclass type. Look for more opportunities to use abstraction by finding two or more subclass that might need common behavior. When you call a method on an object reference, you"re calling the most specific version of the method for that object type. If class b extends class a, class b is-a class a. If you don"t want to completely replace the superclass version of a method, use super. mymethod() followed by whatever you want to add. Instance variables cannot be overridden, but they can be redefined in the subclass. Define a common protocol for a group of classes. Polymorphism = any subclass of a supertype can be substituted where the supertype is expected.
