Polymorphism: CS 310 Lecture notes

Object-Oriented Programming with Java Lecture Notes

19 February 2009 • Polymorphism


Outline

  • Polymorphism

  • Abstract classes.

  • Object-Based polymorphism.

    • Weak generics.

    • Object subclass responsibilities.

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Protocol Classes

Abstract Methods

Abstract-Method Example

Another Protocol-Class Property

Abstract Class

Abstract-Class Methods

Abstract Classes and Inheritance

Abstract-Class Types

Abstract Type Example

The Object Class

Object Polymorphism

Casting

Object-Casting Problems

Generics

Object Methods

Equality

Identity vs. Simularity

Object.equals()

Equality Contract

Contract Rules

Equality Example

public boolean
equals(Object o)
  if this == o     // reflexive
    return true

  if o == null     // null rejecting
    return false;

  if getClass() != o.getClass()
    return false

  final Card c = (Card) o
  
  return 
    c.suit == suit && 
    c.rank == rank

Equality vs. Inheritance

Equality Example.

Equality Example..

Equality Example...

Equality Example....

Equality Example.....

Equality Example......

Object.hashCode()

hashCode() Example

Object.toString()

Summary

Credits


This page last modified on 22 February 2008.

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